COMPARATIVE OVERVIEW
Research Peptide Fundamentals research peptides — Five Compounds Compared
Structured side-by-side across mechanism class, what each has been studied for, evidence maturity, regulatory status, and anti-doping standing.
The short version
These five compounds sit in genuinely different scientific categories and have very different evidence profiles. The table below structures the comparison; the paragraphs after it flag the most important cross-compound distinctions. Reading this comparison alongside the individual compound pages gives the most accurate picture.
Comparison table
| Compound | Class | Primary research area | Key mechanism | Evidence stage | Best human data | Regulatory status | WADA |
|---|---|---|---|---|---|---|---|
| BPC-157 | Gastric pentadecapeptide (research chemical) | Tissue repair, cytoprotection, angiogenesis | VEGFR2-Akt-eNOS; FAK-paxillin; GH-receptor sensitization in tendon | Animal-model (rodent); 3 small human pilots | First-in-human IV pilot (n=2); 2025 narrative review [1][2] | Not approved anywhere; not 503A-eligible for compounding (US) | Prohibited (S0, non-approved substances) |
| Retatrutide | Investigational triple-agonist peptide drug | Obesity, type 2 diabetes, liver steatosis | GIP + GLP-1 + glucagon receptor triple agonism [8][9] | Phase 3 clinical trials (TRIUMPH) | 48-week Phase 2 RCTs: -24.2% body weight, -82.4% liver fat [10][11] | Investigational only; not approved anywhere (FDA, EMA) | Not prohibited (verify current WADA list) |
| Ipamorelin | Selective GHS-R1a agonist (research chemical) | GH secretagogue; growth hormone axis | Selective pituitary somatotroph GH-pulse induction via GHS-R1a [16] | Animal models; one failed Phase 2 RCT; 1 acute human PK/PD study | Phase 2 RCT (n=114) failed primary endpoint; PK study (n=8 per dose) [15][16] | Not approved; removed from 503A Category 2 list (2024, US) | Prohibited (S2, GH secretagogues) |
| GHK-Cu | Copper-chelated tripeptide (cosmetic ingredient / research peptide) | Skin matrix remodeling, collagen synthesis, hair follicle | Fibroblast collagen/elastin/GAG stimulation; MMP rebalancing; gene expression [19][21] | Small controlled human topical trials; animal/cell models for systemic claims | Hair-loss RCT (n=45); skin collagen studies; human skin penetration [20][22] | Legal cosmetic ingredient (topical, US/EU/UK); injectable/systemic: unapproved research chemical | Not prohibited |
| NAD+ | Endogenous dinucleotide coenzyme (dietary supplement / IV therapy) | Cellular energy, DNA repair, aging biology | Redox electron shuttle; sirtuin/PARP/CD38 substrate; NAMPT-dependent salvage [26] | Multiple double-blind RCTs of precursors (NMN, NR); clinical outcomes inconsistent | NMN RCT (n multicenter): blood NAD+ ↑, walking distance improved [24]; NMN insulin-sensitivity RCT [25] | Dietary supplement (US/most markets); NMN FDA status contested; IV compounded form subject to recall | Not prohibited |
Key distinctions across the five compounds
Evidence maturity is not uniform. Retatrutide has published Phase 2 RCTs in hundreds of humans with pre-registered endpoints and independent statistical review. BPC-157 has thousands of animal-model studies and three uncontrolled human pilot reports. These are not equivalent forms of evidence, even though both appear in the same research-community conversations. The table above distinguishes them; the individual pages make the gap explicit.
Regulatory status spans four distinct categories. BPC-157 and Ipamorelin are research chemicals with no approved human use and, in the US, reduced compounding access. Retatrutide is an investigational drug — a fundamentally different regulatory category that includes Phase 3 clinical trials and an active FDA IND, but still no approval. GHK-Cu is simultaneously a legal cosmetic ingredient (topical) and a research chemical (other routes). NAD+ is a dietary supplement (with caveats around NMN's contested status). These distinctions matter practically for anyone reading published trials: trial-conducted evidence does not authorize non-trial use, regardless of category.
The WADA distinction is operationally important. BPC-157 and Ipamorelin are prohibited in sport at all times. GHK-Cu and NAD+ are not on the current prohibited list. Retatrutide's status as an investigational agent should be confirmed against the current WADA Prohibited List before any athletic-research context, as the WADA catch-all S0 category can apply to non-approved pharmacological substances.
'Research peptide' describes the community framing, not a consistent regulatory category. NAD+ is a coenzyme, not a peptide. Retatrutide is an IND-bearing drug candidate. GHK-Cu is a cosmetic ingredient in its primary application. Treating these five compounds as members of a single regulatory or scientific category obscures more than it clarifies; the individual compound pages are the authoritative reference for each one.