How PeptideAtlas rates the strength of evidence for peptide-related claims, from approved medicines (A) to insufficient evidence (E).
Filed under glossary tools, written for beginner, patient-consumer, researcher, journalist.
Not medically reviewed. Last updated 2026-04-10. Nothing here is medical advice.
PeptideAtlas uses a standardized evidence rating system to help readers quickly assess the strength of evidence behind peptide-related information.
The peptide is an approved pharmaceutical product with strong clinical evidence from large-scale randomized controlled trials. Examples: semaglutide, liraglutide, calcitonin.
Evidence from multiple human clinical trials supports the peptide's use or mechanism, but it may not be approved for the specific indication discussed. Example: BPC-157 for GI applications (limited human data but multiple studies).
Some human data exists, but it may be from small studies, single trials, pilot studies, or show mixed results. Evidence is promising but not conclusive.
Evidence comes only from animal models, cell cultures, or in vitro studies. While useful for understanding mechanisms, these results cannot be directly applied to humans.
Claims are based primarily on theoretical mechanisms, anecdotal reports, or studies too preliminary to draw conclusions.
Indicates a regulatory, safety, contamination, or misuse concern. This flag may appear alongside any evidence level.
Content based on official warnings or safety communications from regulatory agencies (FDA, Health Canada, EMA, WADA).
Content reflecting recent regulatory changes, advisory committee meetings, or policy updates.
These ratings are educational tools, not medical recommendations. A Level A rating means strong evidence exists — it does not mean the peptide is appropriate for any individual. Always consult a healthcare provider.
More guides: All guides, Safety centre, Peptide library.