Peptide basics
Six of seven cognitive peptides here have no human trial at all
On this page
The compounds here are grouped into nine categories, and their evidence records differ enormously.
Cognitive, mood and sleep is the thinnest: of seven compounds, six have no registered human trial.
Tissue repair is next: eight compounds, 16 verified trials and 1,550 participants between them, and no approved product.
Metabolic is the strongest by a wide margin, holding most of the approved products and almost all the enrolment on the site.
This page compares the evidence record across the nine categories tracked here. A thin record means little has been published, not that a category is dangerous or worthless. No dose, schedule or route appears.
The thinnest: cognitive, mood and sleep
Seven compounds sit in this group: semax, selank, cerebrolysin, dihexa, noopept, DSIP and pinealon. Six of them have no registered human trial naming them as an intervention. The seventh, cerebrolysin, has 39.1
Take cerebrolysin out and the category's entire registered human evidence base is zero, across compounds drawing tens of thousands of encyclopedia readers a month between them.14
Concentrated in one compound: skin and hair
Seven compounds, 44 verified trials and 2,109 participants — but 23 of those trials and most of the participants belong to melanotan I, which is afamelanotide and holds an approved product. Strip that one out and the rest of the category has 21 trials between six compounds. Palmitoyl pentapeptide-4 and acetyl octapeptide-3 have none.1
Here the reason is structural rather than mysterious. Most of these are regulated as cosmetic ingredients, and cosmetics are not required to demonstrate effectiveness before sale. No requirement, no trials.3
The one with no approvals at all
Tissue repair is a different kind of thin. Its eight compounds include some of the most-read on the site — BPC-157 alone draws 31,331 monthly views — and not one of them has an FDA-approved product.124
It is the sharpest gap on this site between how much attention a group receives and how much has been established about it.1
The strongest: metabolic
Nineteen compounds, holding most of the approved products tracked here and the overwhelming majority of all trial enrolment. It is the only category where the practical question is which compound rather than whether any of them have been studied.12
Why the differences exist
Three forces explain most of it: whether a regulator requires trials, whether a sponsor can recover the cost of running them, and whether the research tradition behind a compound publishes in indexed English-language journals.13
None of those three has anything to do with whether a compound works. That is exactly why the category-level pattern is worth knowing before reading any individual claim.1
Common questions
Are the categories standard?
They are this site's editorial groupings, chosen to match how people actually search. They are not medical classifications.
Does a thin category mean those compounds do not work?
No. It means there is little or no trial evidence to read, which is a statement about the record rather than about the compounds.
Why is metabolic so far ahead?
Large approvable markets attract the funding that trials require. Evidence follows commercial incentive more closely than it follows scientific interest.
Sources
- RegulatoryClinicalTrials.gov API v2 — verified interventional records by compoundU.S. National Library of Medicine, 2026clinicaltrials.gov/data-api/api ↗↩ Back to text
- RegulatoryDrugs@FDA — approved drug products databaseU.S. Food and Drug Administration, 2026www.accessdata.fda.gov/scripts/cder/daf/ ↗↩ Back to text
- RegulatoryFDA — Is It a Cosmetic, a Drug, or Both?U.S. Food and Drug Administration, 2025www.fda.gov/cosmetics/cosmetics-laws-regulations/it-cosmetic-dru ↗↩ Back to text
- Secondary sourceWikimedia REST API — English Wikipedia pageviewsWikimedia Foundation, 2026wikimedia.org/api/rest_v1/#/Pageviews%20data ↗↩ Back to text