How this site classifies the strength of evidence for each peptide, from FDA-approved to preclinical-only.
Our Evidence Classification System
Every peptide profiled on this site is assigned an evidence tier based on the highest level of clinical evidence available. This system helps readers quickly assess the strength of evidence behind any given compound.
Tier 1: FDA-Approved
Peptides that have completed Phase 3 clinical trials and received FDA approval for at least one therapeutic indication. Examples: Semaglutide, Tirzepatide, Bremelanotide (PT-141).
Tier 2: Phase 2-3 Clinical Trials
Peptides with active or completed Phase 2 or Phase 3 human clinical trials, but without FDA approval. Examples: SS-31/Elamipretide, Retatrutide.
Tier 3: Phase 1-2 Clinical Data
Peptides with Phase 1 safety data or early Phase 2 efficacy data in humans. Examples: Ipamorelin, CJC-1295, GHRP-2.
Tier 4: Preclinical Only
Peptides studied only in animal models (in vivo) or cell cultures (in vitro), with no published human clinical trials. Examples: BPC-157 (mostly), Epithalon, Dihexa.
Special: Limited Human Data (Non-Western)
Some peptides (e.g., Semax, Selank) are approved medications in Russia or other countries but lack clinical validation through Western regulatory standards (FDA, EMA). These are noted separately.
Why This Matters
The peptide research space contains significant hype. Many claims circulating online are extrapolated from animal studies or in vitro experiments, which frequently do not translate to human efficacy. Our evidence tier system helps readers distinguish between well-validated therapeutics and compounds with only preliminary research support.
Research Disclaimer
This article is compiled from peer-reviewed research and publicly available scientific literature. It is intended for educational and informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before making health-related decisions.