Peptides A-Z: An Evidence-First Guide to Every Peptide We've Reviewed

"Peptides" has become a catch-all marketing term covering everything from FDA-approved obesity medicines to unapproved grey-market research chemicals sold for fat loss, muscle, tanning, sleep, and anti-aging. This guide is an evidence-first index: every peptide we have reviewed, grouped by what it is actually used for, each with a one-line verdict and a link to the full review. The honest through-line is that the medicines with large, replicated human weight-loss trials are the GLP-1 and GIP drugs — semaglutide (-14.9% in STEP-1 ^[1]) and tirzepatide (-20.9% in SURMOUNT-1 ^[2]) — while most of the "peptides" sold online for weight loss have little or no human evidence for that use.

How to read any peptide claim

• Is it FDA-approved, and for what? A few are (tirzepatide, semaglutide; bremelanotide as Vyleesi for sexual desire). Most "research peptides" are not approved for anything, and "approved abroad" is not the same as proven.
• Is there a human randomized trial for the claimed use? Many peptides have only animal or mechanistic data. "Promising in mice" is not evidence of a human benefit.
• Who funded and replicated the studies? Be cautious when the only positive data come from a single group, or from the seller.
• What is the product, really? Grey-market vials have no guarantee of identity, dose, sterility, or purity, and injecting unregulated peptides carries real risk.

Weight-loss & metabolic peptides

• Peptides for weight loss: the full evidence review — the definitions, the three categories, and which actually have human data
• Non-GLP-1 peptides for fat loss — the broader landscape of what is and isn't supported
• Tesamorelin (Egrifta) — FDA-approved, but only for HIV-associated visceral fat; not a general weight-loss drug
• Cagrilintide — investigational amylin analogue (the amylin half of CagriSema)
• MOTS-c — mitochondrial "exercise mimetic"; mouse metabolism data, no human weight-loss trial
• 5-Amino-1MQ — oral NNMT inhibitor (not a peptide); fat loss in obese mice, zero human trials
• AOD-9604 — built as an anti-obesity drug; positive in mice, negative in the human phase 2
• Tesofensine — strong phase-2 obesity data (TIPO-1) that stalled in phase 3; not approved

Growth-hormone secretagogues (GH/IGF-1 peptides)

• Sermorelin — GHRH analogue once approved (Geref) for pediatric GH deficiency, now discontinued; no weight-loss RCT
• CJC-1295 (and the CJC-1295/ipamorelin stack) — long-acting GHRH analogue; no FDA approval, no weight-loss RCT
• Ipamorelin — selective GH secretagogue; its only clinical RCT was for post-op ileus
• MK-677 (ibutamoren) — oral ghrelin mimetic that actually raises appetite and body weight, not fat loss

Recovery, longevity & other research peptides

• BPC-157 — "Body Protection Compound"; animal-only healing data, no human RCT, no fat-loss mechanism
• TB-500 — thymosin beta-4 fragment; WADA-banned recovery peptide, animal-only, no human trial
• GHK-Cu (copper peptide) — real but modest topical skin evidence; injectable systemic use is unproven
• Epitalon (epithalon) — telomerase/longevity claims resting on thin, single-group, unreplicated data
• Thymosin alpha-1 (Zadaxin) — immune peptide approved abroad for hepatitis; not FDA-approved, not for weight loss
• Semax — Russian intranasal nootropic; mostly Russian-language, unreplicated human data
• Selank — Russian anxiolytic peptide; small, unreplicated clinical data
• DSIP (delta sleep-inducing peptide) — named for a sleep effect, but the human evidence is old, small, and inconsistent
• PT-141 (bremelanotide) — FDA-approved as Vyleesi for sexual desire disorder; not a weight-loss peptide
• Melanotan 2 — unapproved tanning peptide that regulators warn against; linked to changing moles and melanoma