# PEPTIDES.md — Therapeutic Peptides Through the Bioenergetic Longevity Lens

> Sibling document to SUPPLEMENTS.md. Same tier philosophy, same framework lens (pro-mitochondrial, pro-thyroid, pro-glucose-oxidation, anti-PUFA, anti-mTOR-inhibition, pro-anabolic-capacity), but scoped to peptide pharmacology — a class of compounds that has exploded in popular longevity culture in the last decade but suffers from a stark mismatch between marketing claims, animal data, and rigorous human RCT evidence.

> **Important framing note before reading:** Most peptides in this document have one or two orders of magnitude less rigorous human evidence than the supplements covered in SUPPLEMENTS.md. The Sikiric group's three decades of BPC-157 work in rodents is impressive, but the human RCT base for BPC-157 is essentially zero. The Khavinson school bioregulator literature is poorly replicated outside Russian institutions. Mitochondrial peptides (MOTS-c, Humanin, SS-31) have promising mechanistic stories but small human trials. **Tier classification in this document reflects framework mechanistic alignment plus evidence quality plus safety margin — not popularity in the longevity peptide subculture.**

> **Sourcing reality check:** With the exception of FDA-approved peptides (semaglutide, tirzepatide, tesamorelin, sermorelin in some jurisdictions, PT-141), every peptide in this document is sold through the "research chemical" grey market. Purity, identity, endotoxin load, and contaminant burden vary enormously between suppliers. Self-experimentation with unverified material from unregulated suppliers carries risks separate from the pharmacology of the peptide itself. This is repeatedly flagged throughout.

---

## Table of Contents

**Framework Introduction**

- [The bioenergetic framework applied to peptide pharmacology](#framework-introduction)
- [Why peptides as a class — and why caution](#why-peptides-as-a-class)
- [Routes of administration and bioavailability primer](#routes-and-bioavailability)
- [The "research chemical" sourcing problem](#sourcing-problem)
- [Cancer concerns for growth-promoting peptides](#cancer-concerns)

**Tier 1 — Strongly Aligned (direct mitochondrial / regenerative mechanisms with reasonable evidence)**

- 1.1 [MOTS-c](#11-mots-c)
- 1.2 [SS-31 (Elamipretide)](#12-ss-31-elamipretide)
- 1.3 [Humanin](#13-humanin)
- 1.4 [Thymosin α-1 (Zadaxin)](#14-thymosin-α-1)

**Tier 2 — Aligned, Context-Dependent (specific clinical use cases with framework consistency)**

- 2.1 [BPC-157 (Body Protection Compound)](#21-bpc-157)
- 2.2 [TB-500 / Thymosin β-4](#22-tb-500--thymosin-β-4)
- 2.3 [GHK-Cu (Copper Tripeptide)](#23-ghk-cu)
- 2.4 [Pentadeca-Arginate (PDA)](#24-pentadeca-arginate-pda)
- 2.5 [LL-37 / Cathelicidin](#25-ll-37--cathelicidin)
- 2.6 [Selank](#26-selank)
- 2.7 [Semax](#27-semax)
- 2.8 [DSIP (Delta Sleep-Inducing Peptide)](#28-dsip)
- 2.9 [Thymalin](#29-thymalin)

**Tier 3 — Mixed / Complicated (real effects but framework concerns)**

- 3.1 [Tesamorelin (FDA-approved GHRH analogue)](#31-tesamorelin)
- 3.2 [Sermorelin](#32-sermorelin)
- 3.3 [CJC-1295 (with and without DAC)](#33-cjc-1295)
- 3.4 [Ipamorelin](#34-ipamorelin)
- 3.5 [Hexarelin](#35-hexarelin)
- 3.6 [MK-677 / Ibutamoren (oral GHS — not a peptide; included with note)](#36-mk-677--ibutamoren)
- 3.7 [Cerebrolysin](#37-cerebrolysin)
- 3.8 [PT-141 / Bremelanotide](#38-pt-141--bremelanotide)
- 3.9 [Kisspeptin-10](#39-kisspeptin-10)
- 3.10 [Melanotan I (Afamelanotide / Scenesse)](#310-melanotan-i)

**Tier 4 — Avoid (framework-misaligned or poorly evidenced)**

- 4.1 [Melanotan II](#41-melanotan-ii)
- 4.2 [Khavinson School Bioregulators — Epitalon, Vesugen, Pinealon and the wider "peptide bioregulator" pharmacopoeia](#42-khavinson-school-bioregulators)
- 4.3 [Semaglutide / Tirzepatide → cross-reference SUPPLEMENTS.md Section 4.7](#43-glp-1-agonists)

---

<a id="framework-introduction"></a>

## Framework Introduction

### The bioenergetic framework applied to peptide pharmacology

The framework that governs SUPPLEMENTS.md, DIET.md, METABOLISM_AND_AGING.md, and the broader project rests on five pillars:

1. **Pro-glucose-oxidation** — glucose oxidation produces the lowest FADH2:NADH ratio at the electron transport chain (ETC), minimising reverse electron transport (RET) at Complex I and the associated ROS burst; respiratory quotient (RQ) 1.0 is the metabolic state with the smallest oxidative damage footprint per ATP synthesised.
2. **Pro-thyroid** — T3, basal metabolic rate, body temperature; thyroid axis suppression is mechanistically aligned with most accelerated-aging phenotypes.
3. **Pro-mitochondrial** — Complex I-V activity, mitochondrial biogenesis (PGC-1α), membrane potential, fusion/fission balance, mitophagy of damaged units (not blanket mitophagy).
4. **Anti-PUFA** — particularly cardiolipin linoleic acid (LA) replacement, which destabilises Complex IV and predisposes to peroxidation chain reactions (4-HNE, MDA, isoprostanes).
5. **Anabolic capacity** — lean mass preservation; the framework rejects caloric restriction as a chronic strategy and views muscle as both a metabolic sink and a longevity organ.

Peptides interface with this framework in three distinct ways:

- **Direct framework matches:** mitochondrial peptides (MOTS-c, SS-31, Humanin) and regenerative peptides (BPC-157, TB-500, GHK-Cu, PDA) are mechanistically aligned with pillars 3 and 5.
- **Framework tensions:** growth hormone secretagogues (CJC-1295, ipamorelin, MK-677, hexarelin) elevate IGF-1 and activate mTOR. Mainstream longevity culture treats this as anabolic-positive while simultaneously taking rapamycin to *block* mTOR — an internally incoherent stack. The bioenergetic framework's view is that mTOR activation in muscle during anabolic windows is desirable (Pillar 5), but **chronic** elevation of systemic IGF-1 has been associated with cancer incidence in epidemiology (Pollak 2008 *Nat Rev Cancer*) and is mechanistically pro-growth in a way that does not differentiate healthy from neoplastic tissue.
- **Framework irrelevance:** sexual function peptides (PT-141, kisspeptin) and tanning peptides (melanotan I/II) are largely orthogonal to the framework; they get evaluated on their own pharmacology and safety merits rather than slotted into the bioenergetic schema.

### Why peptides as a class — and why caution

Peptides are short polymers of amino acids (typically 2-50 residues — beyond ~50 residues we usually call it a "protein"). Compared with small-molecule drugs they have:

- **High target specificity** — binding via large hydrogen-bond and electrostatic surfaces rather than small hydrophobic pockets; off-target binding is generally rarer.
- **Endogenous-like signalling** — many therapeutic peptides are modified versions of native human signalling peptides (BPC-157 from gastric BPC protein, MOTS-c from mitochondrial 12S rRNA, GHK from a fragment of human α2-macroglobulin / decorin / SPARC).
- **Short half-lives** — most peptides are degraded by serum and tissue proteases within minutes to hours; this is both a safety advantage (clearance is fast) and a practical inconvenience (multiple daily injections, or chemical modification like DAC tags to extend half-life).
- **Poor oral bioavailability** — peptide bonds are hydrolysed by pepsin in the stomach and brush-border peptidases in the intestine; <1% systemic bioavailability is typical for unmodified peptides taken orally. BPC-157 is the controversial exception (Sikiric group claims oral activity; Western pharmacologists are sceptical).

The cautions:

- **Human RCT evidence is sparse.** Most peptide longevity claims rest on rodent data (often from a single lab — Sikiric for BPC-157, Cohen for MOTS-c, Khavinson for the bioregulator series), case reports, or self-experimentation forums. This is a *much* weaker evidence base than what underpins the Tier 1 supplements in SUPPLEMENTS.md (CoQ10's Q-SYMBIO trial, K2's Rotterdam study, B-complex's VITACOG, taurine's Singh 2023 *Science* paper).
- **Cancer concerns for any peptide that promotes angiogenesis, growth, or anti-apoptosis are real but under-investigated.** BPC-157 upregulates VEGF. CJC-1295/ipamorelin elevate IGF-1. TB-500 promotes cellular migration including potentially of metastatic cells. None of these has been adequately studied in cancer-bearing humans.
- **Sourcing is grey-market.** See [§sourcing problem](#sourcing-problem) below.

### Routes of administration and bioavailability primer

| Route | Typical bioavailability | Notes |
|-------|------------------------|-------|
| Subcutaneous (SC) injection | 60-95% | Standard route for most therapeutic peptides; insulin syringes 27-31G |
| Intramuscular (IM) injection | 70-95% | Slightly faster absorption than SC; rarely needed for peptides |
| Intravenous (IV) injection | 100% by definition | Required for some peptides (e.g., SS-31 in trials); home-use rare |
| Intranasal | 1-30% depending on formulation | Effective for some neuropeptides (Selank, Semax, DSIP); olfactory-to-brain route bypasses BBB for small peptides |
| Oral | <1% for most; controversial for BPC-157 | Pepsin and brush-border peptidases destroy peptide bonds; only a handful of peptides survive |
| Sublingual / buccal | 1-10% | Bypasses first-pass metabolism but bioavailability still poor |
| Transdermal | <1% for most | Skin barrier limits >500 Da molecules; GHK-Cu is a notable exception (small, lipophilic-friendly) |

### The "research chemical" sourcing problem

<a id="sourcing-problem"></a>

Almost every peptide in this document is sold by "research chemical" suppliers with disclaimers stating "not for human consumption." This is a legal fiction allowing trade in compounds not approved for therapeutic use.

Real-world consequences:

- **Identity verification.** Some suppliers send the wrong peptide, or a closely-related cheaper peptide. Mass spectrometry by independent labs (e.g., Janoshik Analytical) has documented identity failures across all major peptide categories.
- **Purity.** HPLC purity ranges from claimed 99% to actual 50-70% in some batches; the remainder is truncated synthesis products, racemised residues (D-amino acids replacing L-), and synthesis solvents.
- **Endotoxin contamination.** Lipopolysaccharide (LPS) from bacterial contamination during synthesis or lyophilisation; injecting LPS-contaminated peptide causes systemic inflammation and can mask or mimic the peptide's true effects.
- **Bacteriostatic water quality.** The diluent used to reconstitute lyophilised peptide should be benzyl alcohol-preserved sterile water; non-sterile diluent introduces bacterial contamination.
- **No regulatory oversight.** No GMP. No batch testing. No adverse event reporting.

Mitigations (partial): order from suppliers who post third-party HPLC and mass spectrometry COAs for each batch, prefer suppliers who use Janoshik or similar independent testing, never inject peptide reconstituted in tap water or unsterile saline.

### Cancer concerns for growth-promoting peptides

<a id="cancer-concerns"></a>

A unifying concern across BPC-157, TB-500, all GH secretagogues, MK-677, IGF-1 mimetics, and to a lesser extent GHK-Cu:

- **VEGF and angiogenesis.** BPC-157's wound-healing mechanism includes VEGF upregulation. VEGF is the central driver of tumour angiogenesis; bevacizumab (anti-VEGF antibody) is an established cancer therapeutic precisely because blocking VEGF starves tumours. A peptide that *promotes* VEGF should be presumed to *promote* tumour angiogenesis in the presence of occult or established malignancy. No human cancer trials exist.
- **IGF-1 elevation.** Sustained IGF-1 elevation is epidemiologically associated with prostate, breast, colorectal cancer incidence (Pollak 2008 *Nat Rev Cancer*). GH secretagogues (CJC-1295, ipamorelin, hexarelin, MK-677, sermorelin, tesamorelin) all elevate IGF-1. Laron dwarfism (GH-receptor deficient) shows extraordinarily low cancer incidence (Guevara-Aguirre 2011 *Sci Transl Med*) — the inverse natural experiment.
- **mTOR activation in dysplastic tissue.** Any anabolic signal that activates mTOR in early-stage transformed cells can theoretically accelerate progression. The framework's position is that mTOR activation in muscle during a deliberate anabolic window (after resistance training, post-meal) is desirable; chronic systemic mTOR drive via injected peptides is harder to compartmentalise.

The honest framing: peptides that promote tissue repair, angiogenesis, and anabolism are likely to be net-positive in healthy individuals with no occult malignancy, and likely to be net-negative in individuals with occult or established cancer. Since occult cancer prevalence rises sharply with age (autopsy series show occult prostate cancer in ~30% of men in their 50s, ~50% in their 70s — Sakr 1993), this concern compounds with age.

---

# Tier 1 — Strongly Aligned

## 1.1 MOTS-c

**Tier:** 1 — Strongly Aligned
**Class:** Mitochondrial-derived peptide (MDP)
**Source:** Encoded in the mitochondrial 12S rRNA gene (MT-RNR1); 16 amino acids; first characterised by Lee/Cohen lab, USC, 2015 (*Cell Metab*)

**Mechanism summary:** AMPK activator; promotes glucose uptake into skeletal muscle independent of insulin via translocation of GLUT4; metabolic stress response peptide that increases in circulation after exercise. Mechanistic match for the framework's pro-glucose-oxidation pillar and Pillar 5 (anabolic capacity preservation via insulin sensitivity).

**Framework alignment:** Strong — endogenous mitochondrial peptide; AMPK activation via energy stress sensing (NOT supraphysiological Complex I inhibition like metformin); promotes muscle glucose oxidation; no known mTOR drive.

Detailed analysis: pending.

---

## 1.2 SS-31 (Elamipretide)

**Tier:** 1 — Strongly Aligned
**Class:** Cardiolipin-targeting tetrapeptide (D-Arg-dimethylTyr-Lys-Phe-NH2)
**Origin:** Szeto-Schiller lab, Cornell, 2004; clinical development by Stealth BioTherapeutics

**Mechanism summary:** Binds selectively to cardiolipin on the inner mitochondrial membrane; stabilises Complex I-IV supercomplex assembly; reduces electron leak and ROS generation; preserves cristae architecture. Tested in clinical trials for Barth syndrome (cardiolipin remodelling defect), primary mitochondrial myopathy, dry AMD, Friedreich's ataxia.

**Framework alignment:** Strong — direct mitochondrial inner-membrane protection; reduces RET-ROS at Complex I; protects cardiolipin (the framework's central concern given LA-loading from dietary PUFA — see SUPPLEMENTS.md Section 3.4); no growth-pathway activation.

**Caveats:** Most Phase 3 trials have produced equivocal or negative results on hard clinical endpoints despite positive mechanistic biomarkers (e.g., the MMPOWER-3 trial for primary mitochondrial myopathy missed primary endpoint). The gap between mechanistic elegance and clinical benefit is the central unresolved question.

Detailed analysis: pending.

---

## 1.3 Humanin

**Tier:** 1 — Strongly Aligned
**Class:** Mitochondrial-derived peptide (MDP); 24 amino acids
**Source:** Encoded in mitochondrial 16S rRNA gene (MT-RNR2); discovered by Nishimoto lab 2001 (originally cloned from AD-resistant brain regions, *PNAS*)

**Mechanism summary:** Cytoprotective peptide; binds Bax to inhibit apoptosis; activates STAT3; reduces Aβ-induced neurotoxicity; circulating levels decline with age. Centenarian offspring have higher circulating humanin levels than controls (Muzumdar 2009).

**Framework alignment:** Strong — endogenous mitochondrial peptide; anti-apoptotic specifically in the context of Bax-mediated mitochondrial permeabilisation (preserves functional mitochondria rather than promoting growth); neuroprotective against Aβ (relevant for APOE ε3/ε4 carriers).

**Caveats:** No commercial human-grade preparation; very limited clinical evidence; analogues (HNG, S14G-humanin) are exclusively research tools.

Detailed analysis: pending.

---

## 1.4 Thymosin α-1

**Tier:** 1 — Strongly Aligned
**Class:** Immune-modulating peptide; 28 amino acids
**Brand:** Zadaxin (FDA orphan drug for chronic hepatitis B/C; approved in 35+ countries outside US)

**Mechanism summary:** Promotes T-cell maturation from CD4+CD8+ thymocytes; upregulates Th1 cytokines (IFN-γ, IL-2); restores immune competence in immunosenescent or immunosuppressed states; clinically used adjunctively for chronic hepatitis, sepsis (Wu 2013 *Crit Care* — sepsis mortality reduction), and as cancer immunotherapy adjunct.

**Framework alignment:** Strong — directly addresses immunosenescence (one of the 12 hallmarks of aging); restores T-cell repertoire diversity; mechanistically distinct from the growth/anabolic peptides and therefore avoids the IGF-1/cancer concerns.

**Caveats:** Strongest evidence is in immunocompromised contexts (chronic viral hepatitis, sepsis, cancer patients on chemotherapy). Healthy-aging benefit is extrapolated. SC injection, typically 1.6 mg twice weekly.

Detailed analysis: pending.

---

# Tier 2 — Aligned, Context-Dependent

<a id="21-bpc-157"></a>

## 2.1 BPC-157 (Body Protection Compound)

> **Tier 2 placement rationale:** BPC-157 is *mechanistically* a strong framework match for tissue regeneration (Pillar 5) and the rodent evidence base is unusually deep for a single peptide (30+ years of work from the Sikiric group at the University of Zagreb). It is placed in Tier 2 rather than Tier 1 because (a) human RCT evidence is essentially zero, (b) the VEGF/angiogenesis mechanism creates a theoretical but real cancer concern that has not been adequately studied, and (c) the oral bioavailability claim that underpins much of the practical use case is contested by mainstream pharmacology. A peptide cannot be Tier 1 — Strongly Aligned in this document if its central practical application rests on disputed pharmacokinetics.

### Discovery and structure

BPC-157 ("Body Protection Compound 157") is a synthetic **pentadecapeptide** with the sequence:

```
Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val
 G   E   P   P   P   G   K   P   A   D   D   A   G   L   V
```

It is a partial sequence (residues 14a-15a of an unidentified region) derived from a putative human protein originally extracted from gastric juice — **"BPC"** — by Predrag Sikiric and colleagues at the University of Zagreb in the early 1990s. The parent BPC protein has never been formally characterised at the genomic level (no UniProt entry, no gene name), which has been a recurring criticism of the field: the entire BPC-157 literature rests on a synthetic 15-mer whose claimed natural source remains nebulous. What is uncontroversial is that the synthetic peptide as administered has reproducible biological effects in rodent models.

Molecular weight 1419.5 Da. Stable in gastric juice (Sikiric group claim — see pharmacology discussion below). Soluble in water and saline.

### Pharmacology — the oral vs subcutaneous controversy

The pharmacokinetic question central to BPC-157 is whether it is **orally bioavailable**. The Sikiric group has repeatedly published claims that BPC-157 is stable in gastric juice (its source environment) and active when administered per os or per drinking-water in rodents. Mainstream peptide pharmacology pushes back: peptide bonds are substrates for pepsin in the stomach (cleaves at hydrophobic residues — L14, V15 of BPC-157 are vulnerable), brush-border peptidases in the duodenum, and aminopeptidases in enterocytes. The Pro-Pro-Pro stretch (residues 3-5) confers some pepsin resistance because pepsin disfavours cleavage adjacent to proline, but the C-terminal Leu-Val is a standard pepsin substrate.

To date there is no published pharmacokinetic study in humans showing oral BPC-157 reaches the systemic circulation at meaningful concentrations. Rodent studies showing oral activity are most parsimoniously explained by *local* gut-epithelial effects (which would still be clinically useful for inflammatory bowel disease and gastric ulcer), rather than systemic activity.

**Practical implication:**
- **Local gut effects (IBD, NSAID-induced gastritis, possibly esophageal ulcer):** oral dosing plausible.
- **Systemic effects (tendon healing, brain injury, fracture):** subcutaneous injection is the route with the strongest rodent evidence base, and the most defensible from first-principles pharmacology.

Subcutaneous BPC-157: bioavailability presumably ~70-90% based on analogous small peptides; half-life is short (estimated minutes to hours; no rigorous human PK data); local site-of-injection effects may matter (e.g., injecting near a tendon injury may produce higher local concentration).

### Proposed mechanisms

Multiple, partially overlapping, none individually proven in humans:

1. **NO / eNOS pathway upregulation.** Sikiric group has published extensively on BPC-157 modulating the NO system — reversing L-NAME-induced hypertension, normalising NO-related cardiovascular pathology. Mechanistically this would explain effects on vascular healing and blood flow to injured tissue.

2. **VEGF upregulation.** Several Sikiric papers report increased VEGF expression in healing tissues with BPC-157 (Tkalcevic 2007 *Eur J Pharmacol*, Hsieh 2017 *Vascul Pharmacol*). VEGF drives angiogenesis — capillary sprouting into wound beds. This is mechanistically the most plausible single explanation for tendon, ligament, and gut healing effects. It is also the basis of the cancer concern (see below).

3. **Growth hormone receptor upregulation in tendon fibroblasts.** Chang et al. 2014 (*J Appl Physiol*) reported that BPC-157 upregulates GH receptor expression on cultured tendon fibroblasts and increases their migratory and proliferative response to GH. This is a partial mechanism explaining the synergy with the GH/IGF-1 axis that the longevity peptide subculture has built protocols around.

4. **FAK-paxillin pathway → fibroblast migration.** BPC-157 accelerates the focal adhesion kinase / paxillin signalling that governs cytoskeletal remodelling and cell migration in fibroblasts (Chang 2011 *J Appl Physiol*). This is mechanistically how a wound contracts and re-epithelialises.

5. **Brain-gut axis / dopaminergic and serotonergic modulation.** A surprising body of rodent work shows BPC-157 effects on neuropsychiatric models — antagonism of haloperidol-induced catalepsy (suggesting dopaminergic modulation), antidepressant-like effects in forced-swim test, anxiolytic effects (Sikiric 2017 *Curr Pharm Des* review). The mechanism is not well-characterised — possibly indirect via gut-brain vagal signalling, possibly direct CNS effects after BBB penetration (unclear if intact peptide crosses).

6. **Reversal of NSAID-induced gut and systemic damage.** This is the area with the most consistent rodent data — BPC-157 protects against diclofenac, ibuprofen, indomethacin damage at multiple organ sites (gut, liver, brain).

```
BPC-157 proposed mechanism network (rodent data; human extrapolation uncertain)
─────────────────────────────────────────────────────────────────────────────────
                                                                             
                  ┌──────────────────────────────────────┐                   
                  │            BPC-157 (SC/PO)           │                   
                  └──┬───────────┬───────────┬───────────┬┘                  
                     │           │           │           │                   
              eNOS/NO↑      VEGF↑       FAK/paxillin   GH-R↑                 
                     │           │           │           │                   
                     ▼           ▼           ▼           ▼                   
              vasorelaxation angiogenesis  fibroblast  GH-responsive         
              endothelial    capillary    migration    tendon/ligament       
              repair         sprouting    cytoskeletal repair                
                     │           │           │           │                   
                     └───────────┴─────┬─────┴───────────┘                   
                                       ▼                                     
                          wound healing / tendon repair                      
                          gut mucosal regeneration                           
                          fracture healing                                   
                                                                             
                  parallel: dopaminergic / 5-HT modulation                   
                          → CNS effects (mood, motor)                        
```

### Rodent evidence base — the Sikiric corpus

The Sikiric group has published >150 papers on BPC-157 over three decades. The breadth of indications is unusual and, depending on perspective, either remarkable or suspicious:

- **Tendon healing** — Achilles tendon transection model (Krivic 2008 *J Orthop Res*); accelerated reattachment, increased tensile strength.
- **Ligament healing** — medial collateral ligament transection (Cerovecki 2010 *J Orthop Res*).
- **Muscle injury** — gastrocnemius crush, denervation atrophy (Novinscak 2008 *Med Sci Monit*); accelerated functional recovery.
- **Skin wound** — full-thickness incision, burn, deep wound models; accelerated closure.
- **Bone fracture** — segmental defect of rabbit mandible (Sebecic 1999 *Bone*); accelerated callus formation.
- **Inflammatory bowel disease** — multiple ulcerative colitis models (TNBS, DSS); accelerated mucosal healing, reduced inflammation (Veljaca 1995 *J Pharmacol Exp Ther* — early work).
- **Gastric ulcer** — stress ulcer, ethanol-induced, NSAID-induced models; cytoprotection appears to be the original framing that gave the peptide its name.
- **Hepatic protection** — paracetamol, CCl4, restraint-stress liver injury models.
- **Traumatic brain injury** — closed-head injury models; reduced lesion volume, improved neurological score (Vukojevic 2018 *Neural Regen Res*).
- **Spinal cord injury** — improved motor recovery in rat hemisection (Perovic 2019 *Med Hypotheses*).
- **Cardiovascular** — reversal of L-NAME-induced hypertension; protection in arrhythmia models; reduction of QT prolongation by neuroleptics.
- **Diabetes-related ulcer healing** — accelerated wound closure in alloxan-diabetic rats.

The Sikiric group operates with a consistent experimental design language across these papers — typically rat models, BPC-157 administered IP, IM, SC, or per drinking water at doses ranging 10 ng/kg to 10 µg/kg, with controls of saline ± Pliva (a Croatian pharmaceutical). The consistency of methodology is a strength for internal reproducibility within the lab; the corresponding weakness is that almost all positive BPC-157 evidence comes from a single research group, which violates a basic epistemic principle of multi-lab confirmation.

**Independent replication outside Sikiric group:** thin but non-zero. Chang group (Taiwan) has published independently on tendon fibroblast effects (2011, 2014). Huang group (China) on diabetic wound healing. Most independent work has been published in lower-impact journals; major Western academic centres have not taken up the peptide in a sustained way.

### Human evidence — the critical gap

**There are essentially no rigorous human RCTs on BPC-157.** A 2019 search of ClinicalTrials.gov returned no registered trials. The "evidence" base for human use consists of:

- A small number of case reports (typically self-published or on peptide subculture forums).
- Self-experimentation reports on Reddit, peptide forums, and longevity podcasts.
- Anecdotal reports from sports medicine practitioners using BPC-157 off-label.

The Sikiric group itself has published exactly one human safety study (Sikiric 1993 *Acta Pharmacol Toxicol Hung*) on the parent BPC protein (not BPC-157 the peptide), reporting safety at oral doses up to 10 mg in 70 patients — this is an early-1990s safety dossier, not an efficacy trial, and does not transfer to the 15-mer peptide.

**This is the single most important fact about BPC-157.** The supplement is recommended by some practitioners and used by many self-experimenters on the basis of a rodent literature that — even if every paper is taken at face value — is rodent literature. The translational success rate from positive rodent musculoskeletal-healing data to positive human RCT data is well below 50%.

### The cancer concern

BPC-157 upregulates VEGF and promotes angiogenesis. This is the central mechanism of its wound-healing efficacy. It is also a mechanism that, in the presence of occult or established malignancy, would be expected to promote tumour angiogenesis and progression.

The empirical question: has BPC-157 been tested in tumour-bearing rodents? **Surprisingly little.** A 2019 Sikiric-group paper (Lojo 2016 *Inflammopharmacology*) reported BPC-157 did not promote VX2 carcinoma growth in rabbits — but this is one paper, in one tumour model, from the originating lab, and the negative finding is the harder result to interpret (could reflect insensitivity of the model rather than absence of effect).

Published human cancer signal: none, because there are no human studies of any size.

**Practical framework position:**
- Healthy adults using BPC-157 for acute tendon/ligament injury at standard doses for limited durations (4-8 weeks) are probably at low cancer-promotion risk in absolute terms.
- Chronic continuous use (months to years) in older adults with rising age-associated occult tumour prevalence is harder to defend.
- Use in individuals with active malignancy or recent malignancy is strongly contraindicated on first principles.
- Use in individuals with strong family history of hormonally-driven cancer (prostate, breast) deserves extra caution.

### Safety profile

In rodent studies and case-report human use, BPC-157 has a clean acute safety profile — no serious adverse events reported even at very high doses (10 mg/kg in some rat studies, vs typical human dose ~5 µg/kg = a >1000-fold safety margin).

The unknowns:
- Long-term carcinogenicity (no studies).
- Long-term immunogenicity (anti-BPC-157 antibodies could develop with chronic SC injection; not studied).
- Cardiovascular effects of chronic VEGF and NO modulation (theoretical concern with angiogenesis-promoting agents — could destabilise atherosclerotic plaque vascularisation).
- Effects on diabetic retinopathy or wet AMD (any VEGF promoter should be presumed contraindicated in these conditions).

### Dosing protocols (commonly used; not endorsed)

| Indication | Route | Dose | Frequency | Duration |
|------------|-------|------|-----------|----------|
| Tendon/ligament injury (local) | SC near injury site | 250-500 µg | 1-2x daily | 4-8 weeks |
| Systemic recovery | SC abdomen | 250-500 µg | 1-2x daily | 4-8 weeks |
| Gut healing (IBD, NSAID damage) | Oral (if active) | 250-500 µg | 2x daily | 4-12 weeks |
| Post-surgical recovery | SC | 500 µg | 1-2x daily | 2-6 weeks |

Reconstitution: typically 5 mg lyophilised peptide in 5 mL bacteriostatic water = 1 mg/mL; 250 µg dose = 0.25 mL = 25 units on an insulin syringe. Refrigerate after reconstitution; use within 30-60 days.

### Genotype interactions

- **9p21.3 CDKN2B-AS1 (ANRIL) CC/GG risk genotypes for CAD:** angiogenesis modulation has theoretically opposing effects in CAD — coronary collateralisation could benefit, but plaque neovascularisation could destabilise. No data either way. Cautious extrapolation: use the shortest effective duration; avoid chronic dosing in CAD-risk individuals.
- **COL1A1 Sp1 AA (collagen type I α1):** this is the *common* genotype with normal type I collagen production; relevant to wound healing capacity. No direct interaction with BPC-157 mechanism but the underlying collagen substrate availability is normal.
- **GHR (growth hormone receptor) polymorphisms:** BPC-157 upregulates GH-R on tendon fibroblasts (Chang 2014); individuals with GHR exon 3 deletion (GHRd3) have altered GH responsiveness which could theoretically interact with this mechanism. No published interaction.
- **VEGF -2578 / -1154 / -634 promoter polymorphisms:** affect baseline VEGF expression; high-VEGF-baseline individuals theoretically need less BPC-157, low-VEGF individuals may have greater response. Not clinically actionable.
- **APOE ε3/ε4:** brain-injury models suggest BPC-157 reduces lesion volume in TBI — relevant if traumatic head injury occurs; not a routine longevity indication.

### Stack interactions

Commonly co-stacked (in self-experimentation):

- **TB-500 (Thymosin β-4)** — see §2.2. The "BPC-157 + TB-500" stack is the most popular regenerative protocol in peptide forums; mechanistic rationale is complementary (BPC-157 → angiogenesis + GH-R upregulation; TB-500 → actin sequestration + cell migration + anti-inflammatory). No human evidence for synergy beyond mechanistic plausibility.
- **GHK-Cu** — see §2.3. Often added for skin and connective tissue effects; copper-tripeptide upregulates SOD, MMP regulators, anti-inflammatory cytokines.
- **CJC-1295 / Ipamorelin** — see §3.3, §3.4. Adds systemic IGF-1 elevation to the BPC-157 GH-R upregulation in tendon. Framework caution applies — this stack drives systemic mTOR.
- **Collagen / glycine / vitamin C** — supports the collagen-synthesis substrate side of wound healing; framework-aligned (SUPPLEMENTS.md §2.1, §2.9).

### Sourcing concerns

BPC-157 is one of the most commonly counterfeited peptides because demand is high. Specific concerns:

- **Identity verification.** Independent mass spec testing has found "BPC-157" products that were truncated (missing 1-2 C-terminal residues), or actually different peptides.
- **Pentadecapeptide vs "BPC-157 Arginate" (PDA) confusion.** PDA (see §2.4) is a different compound being marketed by some suppliers as a "more stable" or "more bioavailable" BPC-157. The pharmacology of PDA is even less established than that of BPC-157 — it has essentially zero peer-reviewed literature.
- **Bacteriostatic water reconstitution:** always use benzyl-alcohol-preserved sterile water; do not reconstitute with tap water, saline from unsealed containers, or unsterile diluent.

Recommended verification: request COA (certificate of analysis) showing HPLC purity >98% and mass spec confirming molecular weight 1419.5 Da before any use.

### Framework alignment

**Aligned with:** Pillar 5 (anabolic capacity / regenerative capacity preservation). Direct support for connective tissue repair, which is one of the most clinically frustrating limitations of aging — tendon and ligament healing slows dramatically after age 40 and is poorly responsive to conventional medicine.

**Tension with:** the cancer-promotion risk via VEGF/angiogenesis. Less of a framework tension than a general safety concern; the framework does not have a strong position on VEGF per se, but it has a strong position on not adding chronic growth-promoting signals in older adults.

**Verdict:** Tier 2 — Aligned, Context-Dependent. Defensible for **short courses** in acute musculoskeletal injury, IBD flares, post-surgical recovery, and gastritis. Hard to defend as a chronic longevity supplement. The human RCT evidence gap is large enough that anyone using BPC-157 should treat it as experimental self-medication, not as evidence-based therapy.

### Evidence summary table

| Claim | Evidence level | Notes |
|-------|---------------|-------|
| Accelerates rodent tendon healing | Strong (animal) | Multiple Sikiric papers; Krivic 2008 *J Orthop Res*; independent Taiwan replication (Chang 2011) |
| Accelerates rodent gut mucosal healing (IBD, ulcer models) | Strong (animal) | Multiple Sikiric papers; consistent across models |
| Reduces rodent NSAID-induced organ damage | Strong (animal) | Multiple Sikiric papers across gut, liver, brain |
| Upregulates VEGF in healing tissues (rodent) | Strong (animal) | Tkalcevic 2007, Hsieh 2017 |
| Upregulates GH-receptor on tendon fibroblasts (in vitro) | Moderate | Chang 2014 *J Appl Physiol* |
| Orally bioavailable (systemic) | Contested | Sikiric group claims; no human PK data; mainstream pharmacology sceptical |
| Active locally in gut when given orally | Plausible | Local epithelial action explains gut data without systemic absorption |
| Effective for tendon healing in humans | Untested | No human RCTs; case reports only |
| Effective for IBD in humans | Untested | No human RCTs |
| Effective for TBI in humans | Untested | Rodent positive; no human data |
| Carries cancer-promotion risk via VEGF | Hypothesis (mechanistic) | No tumour-promotion seen in one rabbit VX2 model (Lojo 2016); inadequately studied |
| Acute safety in rodents at therapeutic doses | Strong | >1000-fold safety margin in rat studies |
| Long-term human safety | Untested | No long-term human data |
| Long-term carcinogenicity | Untested | No carcinogenicity studies |

### Key references

1. Sikiric P et al. (2010) "Brain-gut Axis and Pentadecapeptide BPC 157: Theoretical and Practical Implications." *Curr Neuropharmacol* — foundational review from originating lab.
2. Sikiric P et al. (2017) "Stable Gastric Pentadecapeptide BPC 157 and Wound Healing." *Front Pharmacol* — comprehensive mechanism review.
3. Sikiric P et al. (2018) "Brain-gut Axis and Pentadecapeptide BPC 157 Beneficial Effects on Various Stab and Crush Wound Effects in Skeletal Muscle and Tendon." *Curr Pharm Des* — musculoskeletal review.
4. Krivic A et al. (2008) "Achilles detachment in rat and stable gastric pentadecapeptide BPC 157: Promoted tendon-to-bone healing and opposed corticosteroid aggravation." *J Orthop Res* — landmark tendon-healing rat study.
5. Chang CH et al. (2011) "The promoting effect of pentadecapeptide BPC 157 on tendon healing involves tendon outgrowth, cell survival, and cell migration." *J Appl Physiol* — independent (Taiwan) replication; FAK-paxillin mechanism.
6. Chang CH et al. (2014) "Pentadecapeptide BPC 157 enhances the growth hormone receptor expression in tendon fibroblasts." *J Appl Physiol* — GH-R upregulation mechanism.
7. Cerovecki T et al. (2010) "Pentadecapeptide BPC 157 (PL 14736) improves ligament healing in the rat." *J Orthop Res*.
8. Tkalcevic VI et al. (2007) "Enhancement by PL 14736 of granulation and collagen organization in healing wounds and the potential role of egr-1 expression." *Eur J Pharmacol* — VEGF and Egr-1 mechanism.
9. Hsieh MJ et al. (2017) "Therapeutic potential of pro-angiogenic BPC157 is associated with VEGFR2 activation and up-regulation." *Vascul Pharmacol*.
10. Vukojevic J et al. (2018) "Rapid and prolonged effect of stable gastric pentadecapeptide BPC 157 on traumatic brain injury." *Neural Regen Res*.
11. Veljaca M et al. (1995) "BPC-157 reduces trinitrobenzene sulfonic acid-induced colitis in rats." *J Pharmacol Exp Ther* — early IBD model.
12. Sebecic B et al. (1999) "Osteogenic effect of a gastric pentadecapeptide, BPC-157, on the healing of segmental bone defect in rabbits." *Bone*.
13. Lojo N et al. (2016) "Effects of diclofenac, L-NAME, L-arginine, and pentadecapeptide BPC 157 on gastrointestinal, liver, and brain lesions, failed anastomosis, and intestinal adaptation deterioration in 24 h-short-bowel rats." *PLoS One*.
14. Novinscak T et al. (2008) "Gastric pentadecapeptide BPC 157 as an effective therapy for muscle crush injury in the rat." *Med Sci Monit*.
15. Perovic D et al. (2019) "Stable gastric pentadecapeptide BPC 157 can improve the healing course of spinal cord injury and lead to functional recovery in rats." *J Orthop Surg Res*.
16. Sikiric P (1993) "Stable Gastric Pentadecapeptide BPC 157: Novel Therapy in Gastrointestinal Tract." *Acta Pharmacol Toxicol Hung* — early human safety data (parent BPC, not BPC-157 per se).
17. Pollak M (2008) "Insulin and insulin-like growth factor signalling in neoplasia." *Nat Rev Cancer* — general context for IGF-1 / cancer concern relevant to growth-promoting peptides.
18. Sakr WA et al. (1993) "The frequency of carcinoma and intraepithelial neoplasia of the prostate in young male patients." *J Urol* — occult cancer prevalence context.

### Bottom line

**BPC-157 is a synthetic pentadecapeptide with a unique three-decade rodent evidence base supporting tissue-healing efficacy across remarkably diverse contexts — tendon, ligament, gut, brain, liver, bone — but with essentially zero human RCT evidence and an under-investigated theoretical cancer-promotion mechanism via VEGF.** Defensible as short-course (4-8 weeks) self-experimental therapy for acute musculoskeletal injury or IBD flares, with subcutaneous injection near the injury site being the most mechanistically supported route. Hard to defend as a chronic longevity supplement. Anyone using it should source from third-party-tested suppliers, use the shortest effective duration, avoid use during or after active malignancy, and treat the experience as experimental rather than evidence-based medicine.

---

## 2.2 TB-500 / Thymosin β-4

**Tier:** 2 — Aligned, Context-Dependent
**Class:** 43-amino-acid actin-sequestering peptide; endogenous (highly conserved across species); TB-500 is a synthetic fragment of the full Tβ4 molecule
**Source:** Endogenously expressed in nearly all cell types; concentrated in platelets and wound fluid

**Mechanism summary:** Sequesters G-actin (preventing premature polymerisation), promotes cellular migration, upregulates VEGF, anti-inflammatory effects, accelerates wound closure in rodent models including dermal, corneal, cardiac. Commonly stacked with BPC-157.

**Framework alignment:** Tier 2 — supports tissue repair (Pillar 5) but shares BPC-157's cancer-promotion theoretical concern via VEGF and via the promotion of cellular migration (which in dysplastic cells could promote metastasis). Banned by WADA in competitive sports.

Detailed analysis: pending.

---

## 2.3 GHK-Cu

**Tier:** 2 — Aligned, Context-Dependent
**Class:** Copper-binding tripeptide (Gly-His-Lys-Cu²⁺)
**Source:** Endogenously present in human plasma; declines ~60% between ages 20 and 60 (Pickart 2008)

**Mechanism summary:** Modulates >4000 genes (Pickart & Margolina 2018 *Int J Mol Sci* — gene-expression review); upregulates SOD, antioxidant defence; modulates MMPs; stimulates collagen, decorin, glycosaminoglycan synthesis; reduces TGF-β-driven fibrosis. Used topically (cosmetic, hair regrowth, wound healing) and subcutaneously (off-label).

**Framework alignment:** Strong mechanistic alignment with repair and antioxidant pillars; copper supply matters for cytochrome c oxidase (see SUPPLEMENTS.md §2.4). Caveat: chronic copper loading from injected GHK-Cu in non-deficient individuals could push systemic copper status above optimal — relevant for the copper:zinc balance discussion in SUPPLEMENTS.md §2.3 and §2.4.

Detailed analysis: pending.

---

## 2.4 Pentadeca-Arginate (PDA)

**Tier:** 2 — Aligned, Context-Dependent (provisional — pending more data)
**Class:** Arginate salt of a BPC-157-like pentadecapeptide; recent introduction to the peptide market
**Status:** Marketed as a "more stable" or "more bioavailable" BPC-157 variant

**Mechanism summary:** Claimed to share BPC-157's tissue-healing properties with improved stability. Peer-reviewed mechanistic literature is essentially absent — what exists is supplier marketing material and a handful of preprints.

**Framework alignment:** Same theoretical alignment as BPC-157 (regenerative); even more uncertainty because the evidence base is thinner than BPC-157's already-thin human evidence base. Provisional Tier 2 pending more data; could be reclassified upward or downward.

Detailed analysis: pending.

---

## 2.5 LL-37 / Cathelicidin

**Tier:** 2 — Aligned, Context-Dependent
**Class:** 37-amino-acid antimicrobial peptide; the only human cathelicidin; cleaved from hCAP18 precursor
**Source:** Endogenously produced by neutrophils, epithelial cells; production induced by vitamin D (VDR-dependent — relevant to SUPPLEMENTS.md §1.7)

**Mechanism summary:** Broad-spectrum antimicrobial against bacteria, viruses, fungi; immunomodulatory (chemotactic for neutrophils, monocytes, T-cells); promotes wound healing; clinically explored for chronic wound infections, biofilm-associated infections.

**Framework alignment:** Aligned with immune-defence aspect of healthspan; vitamin D status is the most important physiological lever for endogenous LL-37 (D3 → VDR → hCAP18 transcription). Synthetic LL-37 injection is a more aggressive intervention than supporting endogenous production via vitamin D + sun exposure.

Detailed analysis: pending.

---

## 2.6 Selank

**Tier:** 2 — Aligned, Context-Dependent
**Class:** Synthetic heptapeptide; analogue of tuftsin with N-terminal extension
**Origin:** Russian Academy of Medical Sciences, 1990s; widely used in Russia for anxiety disorders

**Mechanism summary:** Anxiolytic without sedation, cognitive enhancement, immunomodulatory; mechanism includes GABA-A modulation, BDNF upregulation, modulation of enkephalin peptidase. Intranasal administration most studied.

**Framework alignment:** Stress-reduction effects align with cortisol-reduction (framework views chronic cortisol as anti-thyroid, pro-catabolic); no growth-pathway concerns. Limited Western evidence base; bulk of human data is Russian-language literature.

Detailed analysis: pending.

---

## 2.7 Semax

**Tier:** 2 — Aligned, Context-Dependent
**Class:** Synthetic heptapeptide; fragment of ACTH (4-7) with C-terminal extension
**Origin:** Russian Academy of Medical Sciences; approved in Russia for stroke recovery

**Mechanism summary:** Nootropic / neuroprotective; upregulates BDNF and NGF; modulates dopaminergic system; some evidence in ischaemic stroke recovery in Russian trials.

**Framework alignment:** Neurotrophic support aligns with brain-healthspan goals; intranasal route bypasses systemic exposure. Same evidence-base caveat as Selank (Russian-dominated literature, limited Western replication).

Detailed analysis: pending.

---

## 2.8 DSIP (Delta Sleep-Inducing Peptide)

**Tier:** 2 — Aligned, Context-Dependent
**Class:** Nonapeptide; originally isolated from rabbit cerebral venous blood during electrical-induced sleep state (Schoenenberger 1977)
**Status:** Not commercially developed despite four decades of research

**Mechanism summary:** Promotes delta-wave (slow-wave) sleep; possibly stress-protective; mechanism poorly characterised after 40+ years — receptor unidentified.

**Framework alignment:** Sleep quality (particularly slow-wave sleep) is one of the highest-leverage longevity inputs; if DSIP genuinely augments SWS without rebound or tolerance, it would be highly framework-aligned. The unresolved mechanism after four decades is a concern — either the effect is real but mediated by a still-unknown receptor, or the effect is weak/inconsistent enough to have stymied mechanistic characterisation.

Detailed analysis: pending.

---

## 2.9 Thymalin

**Tier:** 2 — Aligned, Context-Dependent
**Class:** Polypeptide complex extracted from calf thymus (Khavinson school product)
**Status:** Available in Russia and some Eastern European markets

**Mechanism summary:** Claimed to restore T-cell function; mechanistically presumed similar to thymosin α-1 but the preparation is a complex (not a single defined peptide) which complicates pharmacology.

**Framework alignment:** Conceptually aligned (immunosenescence reversal) but evidence base much weaker than thymosin α-1 because Thymalin is a complex extract rather than a defined molecule. Western replication essentially absent.

Detailed analysis: pending.

---

# Tier 3 — Mixed / Complicated

> **Framework consistency call for §3.1–3.6 (the GH/GHRH/GHRP/GHS class):** All of these peptides (and the non-peptide MK-677) elevate GH and downstream IGF-1. Mainstream longevity culture treats this favourably — restoring "youthful GH/IGF-1 levels." The bioenergetic framework's position is more nuanced: acute pulsatile GH (which is how endogenous GH secretion works) coupled to anabolic windows (resistance training, post-prandial) supports lean-mass preservation (Pillar 5) and is desirable in older adults losing muscle. **Chronic** systemic IGF-1 elevation drives mTOR signalling indiscriminately across all tissues including any incipient neoplastic clones, and is epidemiologically associated with increased cancer incidence (Pollak 2008 *Nat Rev Cancer*; mirror image of Laron dwarfism — Guevara-Aguirre 2011 *Sci Transl Med*). The mainstream-longevity stack that combines GH secretagogues *with* rapamycin to block mTOR is internally incoherent. The framework's position: peptides in this class are Tier 3 (mixed) rather than Tier 1 or Tier 2 because of this growth-axis tension; specific clinical use cases (HIV lipodystrophy for tesamorelin, adult GHD for sermorelin) can be defensible, but the "anti-aging boost" use case is harder to defend on framework grounds.

## 3.1 Tesamorelin

**Tier:** 3 — Mixed / Complicated
**Class:** GHRH (1-44) analogue with N-terminal modification for protease resistance
**Status:** FDA-approved (Egrifta) for HIV-associated lipodystrophy

**Mechanism summary:** Restores pulsatile GH secretion via pituitary GHRH receptor; reduces visceral adipose tissue (5-20% reduction in HIV lipodystrophy trials); modest cognitive benefit shown in MCI (Baker 2012 *Arch Neurol*).

**Framework alignment:** Tier 3 — most rigorous human evidence in the GH-axis class because it's FDA-approved; the visceral fat reduction is mechanistically aligned (visceral adipose tissue is metabolically harmful, framework-anti); the systemic IGF-1 elevation is the framework concern. Use case-dependent — visceral fat in a metabolically unhealthy older adult vs general anti-aging use are very different.

Detailed analysis: pending.

---

## 3.2 Sermorelin

**Tier:** 3 — Mixed / Complicated
**Class:** GHRH (1-29) analogue
**Status:** FDA-approved historically for paediatric GHD (withdrawn from US market 2008 commercially; compounded versions still prescribed)

**Mechanism summary:** Stimulates pulsatile GH release via GHRH receptor; preserves negative feedback (somatostatin still works) so less supraphysiological than exogenous GH.

**Framework alignment:** Same Tier 3 logic as tesamorelin — preserved feedback is a safety advantage over exogenous recombinant GH; chronic IGF-1 elevation remains the framework concern.

Detailed analysis: pending.

---

## 3.3 CJC-1295 (with and without DAC)

**Tier:** 3 — Mixed / Complicated
**Class:** Modified GHRH (1-29) analogue; DAC variant has a drug-affinity-complex tag conferring 7-8 day half-life via albumin binding
**Status:** Research chemical; not FDA-approved

**Mechanism summary:** Same receptor as sermorelin/tesamorelin (GHRH-R); modifications confer protease resistance and (with DAC) extended half-life. The DAC variant produces **continuous** (rather than pulsatile) GH/IGF-1 elevation — this is the central framework concern, because pulsatile and continuous GH have different physiological consequences (pulsatile preserves negative feedback, continuous suppresses it and produces more sustained IGF-1 elevation).

**Framework alignment:** Tier 3 — CJC-1295 *without DAC* (mod-GRF 1-29, short half-life) is the framework-preferable form because it preserves pulsatility; CJC-1295 *with DAC* should be avoided on framework grounds (continuous IGF-1 drive is the worst-case scenario for the cancer-promotion concern).

Detailed analysis: pending.

---

## 3.4 Ipamorelin

**Tier:** 3 — Mixed / Complicated
**Class:** Selective ghrelin receptor (GHS-R1a) agonist; pentapeptide
**Status:** Research chemical; was in Phase 2 clinical trials for post-operative ileus (Helsinn) — development discontinued

**Mechanism summary:** GH secretagogue acting via ghrelin receptor on somatotrophs; more selective than older GHS like GHRP-2 and GHRP-6 (less cortisol and prolactin elevation). Commonly stacked with CJC-1295 (no DAC) for synergistic pulsatile GH release.

**Framework alignment:** Tier 3 — same GH-axis concern; ipamorelin's selectivity (minimal cortisol/prolactin) is a safety advantage over GHRP-2/6 but does not address the IGF-1/cancer concern. The CJC-1295-no-DAC + ipamorelin stack is the framework-preferable form within this class because it produces pulsatile rather than continuous GH elevation.

Detailed analysis: pending.

---

## 3.5 Hexarelin

**Tier:** 3 — Mixed / Complicated
**Class:** Hexapeptide GHS; older-generation
**Status:** Research chemical

**Mechanism summary:** Potent GHS; some evidence of cardioprotective effects independent of GH (CD36-mediated) but elicits more prolactin and cortisol elevation than ipamorelin; tachyphylaxis (desensitisation) develops with chronic use.

**Framework alignment:** Tier 3 — within the GHS class, hexarelin is less preferable than ipamorelin because of the cortisol/prolactin elevation and tachyphylaxis; cardioprotective claims are intriguing but not well-replicated.

Detailed analysis: pending.

---

## 3.6 MK-677 / Ibutamoren

**Tier:** 3 — Mixed / Complicated
**Class:** Non-peptide oral GHS-R1a agonist (included with note — technically not a peptide, but mechanistically and culturally grouped with the GHS class)
**Status:** Research chemical; failed Alzheimer's trial; never approved despite Phase 3 testing

**Mechanism summary:** Oral, long-acting (24-hour half-life) ghrelin receptor agonist; sustained 24-hour elevation of GH and IGF-1; appetite stimulation (ghrelin mimicry); fluid retention; insulin resistance; sleep architecture changes (more slow-wave sleep but also more fragmentation).

**Framework alignment:** Tier 3 leaning toward Tier 4. MK-677 is the *worst* framework match in the GHS class because (a) it produces sustained (24-hour) IGF-1 elevation rather than pulsatile, (b) it induces insulin resistance (anti-framework), (c) it causes water retention often misread as muscle gain, (d) appetite drive can drive overeating, (e) it's oral and easy to take chronically, which compounds the cancer-promotion timeline concern.

Detailed analysis: pending.

---

## 3.7 Cerebrolysin

**Tier:** 3 — Mixed / Complicated
**Class:** Porcine brain-derived neuropeptide preparation (complex, not a single defined peptide); contains low-MW peptides and free amino acids
**Status:** Approved in many European, Asian, and Latin American countries for stroke recovery, vascular dementia, TBI; not FDA-approved

**Mechanism summary:** Claimed BDNF/NGF-mimetic activity; some evidence in acute ischaemic stroke (Cochrane review found modest benefit), MCI, and TBI. Complex undefined composition makes mechanistic characterisation difficult.

**Framework alignment:** Tier 3 — neurotrophic support aligns with brain-healthspan, but the undefined composition is a concern for both reproducibility and safety. Porcine origin raises infection-transmission concerns (theoretical).

Detailed analysis: pending.

---

## 3.8 PT-141 / Bremelanotide

**Tier:** 3 — Mixed / Complicated
**Class:** Synthetic cyclic heptapeptide; melanocortin receptor agonist (MC1R, MC3R, MC4R)
**Status:** FDA-approved (Vyleesi) for hypoactive sexual desire disorder in premenopausal women

**Mechanism summary:** Central nervous system mechanism via MC4R; pro-erectile and pro-libido effects in both sexes; bypasses peripheral vascular mechanisms (works in some PDE5-inhibitor non-responders).

**Framework alignment:** Mostly orthogonal to the bioenergetic framework. Side effects (nausea, hyperpigmentation, blood pressure elevation) and the unclear long-term safety of chronic MC4R agonism warrant the Tier 3 placement. Use case-specific (sexual dysfunction) rather than a general longevity peptide.

Detailed analysis: pending.

---

## 3.9 Kisspeptin-10

**Tier:** 3 — Mixed / Complicated
**Class:** Decapeptide; KISS1R agonist
**Status:** Research chemical; under clinical investigation for hypothalamic hypogonadism

**Mechanism summary:** Stimulates hypothalamic GnRH neurons → LH/FSH → gonadal sex hormone production; preserves HPG axis pulsatility unlike exogenous testosterone or HCG; emerging research interest for hypothalamic hypogonadism in both sexes, sexual response, fertility.

**Framework alignment:** Tier 3 leaning Tier 2 — kisspeptin works at the top of the HPG axis (preserves downstream regulation), which is more physiologically respectful than exogenous testosterone replacement or HCG. Limited human safety data is the limiting factor.

Detailed analysis: pending.

---

## 3.10 Melanotan I (Afamelanotide / Scenesse)

**Tier:** 3 — Mixed / Complicated
**Class:** α-MSH analogue; potent MC1R agonist
**Status:** FDA-approved (Scenesse) for erythropoietic protoporphyria

**Mechanism summary:** Stimulates eumelanin production via MC1R; provides UV-protective tanning; medical indication is genuine (EPP patients have life-disrupting photosensitivity). Off-label cosmetic use for tanning is widespread.

**Framework alignment:** Tier 3 — for genuine medical indication (EPP, vitiligo, photosensitivity disorders) the risk-benefit is favourable; for cosmetic tanning the long-term melanocortin-axis effects and the masking of melanoma warning signs (new dark moles harder to distinguish from drug-induced pigmentation) are concerns. Sunlight exposure (which the framework supports — see SUPPLEMENTS.md §1.7 vitamin D / sunlight discussion) for *non-photosensitive* individuals does not need a melanocortin agonist.

Detailed analysis: pending.

---

# Tier 4 — Avoid

## 4.1 Melanotan II

**Tier:** 4 — Avoid
**Class:** Non-selective melanocortin agonist (MC1R, MC3R, MC4R, MC5R); cyclic heptapeptide
**Status:** Research chemical; never approved for any indication

**Mechanism summary:** Same tanning effect as Melanotan I but with potent MC3R/MC4R/MC5R co-activation → sexual arousal, appetite suppression, blood pressure changes, gastrointestinal effects (nausea), hyperpigmentation including darkening of existing nevi.

**Framework alignment:** Avoid. Non-selective melanocortin agonism is a much more aggressive intervention than Melanotan I; reports of new melanoma in long-term users (causality unestablished but biologically plausible given the masking effect on nevus surveillance); cosmetic-only use case does not justify the safety profile. PT-141 (§3.8) is the more selective, FDA-approved alternative if the goal is sexual function rather than tanning.

Detailed analysis: pending.

---

## 4.2 Khavinson School Bioregulators (Epitalon, Vesugen, Pinealon, and the wider "peptide bioregulator" pharmacopoeia)

**Tier:** 4 — Avoid (with caveat that the evidence question is genuinely unresolved)
**Class:** Short peptides (2-4 amino acids typically) developed by Vladimir Khavinson's group (St Petersburg Institute of Bioregulation and Gerontology, Russia) over ~40 years; claimed to be organ-specific bioregulators (e.g., Epitalon → pineal; Vesugen → vascular; Pinealon → CNS)
**Status:** Sold extensively as research chemicals; some marketed in Russia and Eastern Europe as supplements

**Mechanism summary (claimed):** Tetrapeptide (Epitalon = Ala-Glu-Asp-Gly) said to upregulate telomerase, restore pineal melatonin secretion, normalise circadian rhythm, slow aging. Khavinson group has published claims of lifespan extension in mice, telomere lengthening in human lymphocytes, mortality reduction in elderly cohorts.

**Mechanism summary (skeptical reading):** A 4-amino-acid peptide injected subcutaneously will be degraded by serum peptidases within minutes; the proposed mechanism of organ-specific gene regulation by a 4-mer is mechanistically implausible (4-mers have insufficient information content to bind specific transcription factor sites with high affinity); the Khavinson-group literature is poorly replicated outside the originating institute; the "human cohort" mortality data has methodological weaknesses including non-blinded administration and selection bias.

**Framework alignment:** The mechanistic claims, if true, would be framework-aligned (melatonin restoration → circadian → mitochondrial; telomerase activation → replicative reserve). The mechanistic plausibility and evidence-quality concerns are large enough to recommend avoidance until independent Western replication appears. **Honest assessment: this is one of the largest evidence-quality gaps in the entire peptide field.** Tier 4 placement reflects the evidence-base failure, not certainty that the compounds are inactive.

Detailed analysis: pending.

---

## 4.3 Semaglutide / Tirzepatide / GLP-1 Receptor Agonists

**Tier:** 4 — Avoid (per existing framework position)
**Cross-reference:** See SUPPLEMENTS.md Section 4.7 — GLP-1 Receptor Agonists / Semaglutide for the detailed framework critique.

Summary of framework position (not re-derived here): pharmacological appetite suppression via GLP-1 agonism produces rapid weight loss including substantial lean-mass loss; thyroid C-cell carcinoma signal in rodents (precaution rather than confirmed human risk); muscle-mass loss runs directly counter to framework Pillar 5 (anabolic capacity preservation); the underlying metabolic dysregulation that drives obesity is not addressed by appetite suppression and tends to re-emerge after discontinuation.

Detailed analysis: see SUPPLEMENTS.md §4.7.

---

# End of document

---

## Document metadata

- First created: 2026-05-24
- Scope: therapeutic peptides through the bioenergetic longevity framework lens
- Sibling document: SUPPLEMENTS.md
- Status: BPC-157 deep dive complete; all other entries are stubs pending future expansion
- Framework consistency principle applied: GH/GHRH/GHRP/GHS class placed in Tier 3 not Tier 2 on grounds of chronic IGF-1 → mTOR concern, despite mainstream longevity culture's enthusiasm; mitochondrial peptides (MOTS-c, SS-31, Humanin) and thymosin α-1 placed in Tier 1 as direct framework matches; Khavinson school placed in Tier 4 on evidence-quality grounds; BPC-157 placed in Tier 2 not Tier 1 because of human RCT evidence gap and VEGF/cancer concern.
