How the grades work

Each peptide gets one letter for the use it is best known for. The letter comes from the kind of studies behind that use, not from how often it is talked about and not from whether the FDA has approved the drug for something else.

AStrong human evidence

Approved on the basis of randomised controlled trials, or several RCTs in humans supporting the known use. 64 peptides.

BSome human evidence

At least one controlled human trial, or several consistent human studies, with a gap: small samples, one trial, surrogate endpoints, or approval for a narrow indication while the popular use lacks trials. 43 peptides.

CAnimal and cell studies

Animal or cell studies only, or human evidence limited to case reports and uncontrolled series. 40 peptides.

DNo meaningful data

Marketed claims with no meaningful published data for the claimed use. 5 peptides.

The two one-line summaries at the top of each page and in each list row, "sold for" and "studies say", condense the cited reasoning below them and carry no markers of their own.

FDA status

Status is a separate axis from evidence. A cosmetic peptide is outside drug approval altogether. A compound in clinical trials may have strong early data and still be unapproved. An approved drug can be widely used for something the approval never covered. Stated as of 2026-10-27: 77 approved, 22 in trials, 37 not approved, 16 cosmetic ingredients.

Where the facts come from

The list of compounds, their body systems and their citation lists started from a public spreadsheet of a published peptide library. Every article here was then written from the cited papers' PubMed records and the FDA's own labels and announcements. Each factual paragraph carries a numbered citation that links to the source. Articles are written by a language model under a fixed brief and are not reviewed by a physician; treat them as a reading guide to the literature, not as clinical advice.

What this site leaves out

No dosing. No sourcing. No recommendations. Dosing of unapproved compounds has no evidence base worth repeating, and the approved ones have labels.