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The Peptide Knowledge Base
How we grade

Our method, in the open.

This category was built on overclaim. Our answer is a method you can audit: an evidence grade on every molecule, a separate plain-English verdict on whether you can actually get it, and an honest line about what we still don't know.

The evidence grade: A through E

The grade answers one question only, how strong is the human evidence?It is not a recommendation, a safety score, or a measure of how exciting a molecule sounds. It tracks the quality and quantity of studies in people.

These grades measure how much human evidence exists — not whether a molecule is good, safe, or worth your interest. A low grade usually means the studies haven't been done yet.

A
Strong human evidence
Multiple well-designed randomized controlled trials in humans, often behind an FDA-approved product. Semaglutide, tirzepatide, and PT-141 (bremelanotide) sit here.
B
Good human evidence
Solid human data with some gaps, fewer trials, narrower indications, or shorter follow-up. Real, but not the whole story yet.
C
Mixed / early human evidence
Some human studies, but limited, inconsistent, or older. Mechanism is plausible; outcomes are not settled. Sermorelin and Semax sit around here.
D
Animal and lab evidence; human trials still to come
Interesting mechanism, but the data is mostly preclinical or fewer than a few dozen humans, with no placebo-controlled efficacy trials. This is the largest band we carry, and it is a statement about the literature rather than about the molecule: it means the human trials have not been run yet, not that they were run and failed. BPC-157 and TB-500 sit here.
E
Claims outrun the evidenceReserved · 0 molecules
Reserved for compounds whose marketing claims outrun any credible data. No molecule in this reference currently sits here, and we will not populate it to prove the scale works. A compound with thin or animal-dominant evidence, but no inflated claims attached, is graded D.

Evidence, not marketing

Evidence and overclaim are different measurements. The grade tracks the evidence only, so a compound with thin data is graded D whether or not its marketing is inflated. Where claims outrun the data, we say so in the molecule's own words — not by moving its grade.

A grade never moves because a compound became popular, because its marketing got louder, or because we sell it. It moves when the human evidence changes, through the logged path below.

Two signals, never collapsed

"Is the evidence strong?" and "Can I actually get it?" are different questions, so we answer them with two separate signals, and we never let one stand in for the other. A molecule can be grade A and still not be available; another can be available now and still be grade D.

Signal 1 · Evidence grade
A–E

How good the human science is. Owned by this Knowledge Base and our medical reviewer.

Signal 2 · Availability verdict
The traffic light

Whether you can legitimately get it today. Owned by the FDA Tracker, the Knowledge Base consumes it, never invents it.

Available now Waitlist / coming Not available

Peptides, and related longevity compounds

Most of what we cover are true peptides. A few, NAD+, rapamycin, metformin, are related longevity compounds, not peptides. We cover them because people ask, and we label them plainly so nothing here is ever misrepresented as something it isn't.

What would change a grade

Grades are dated, not permanent. A new randomized human trial, a published replication, a safety signal, or a regulatory action can move a grade or a verdict, and we timestamp every change. When the FDA Tracker logs a status change, the matching monograph is flagged for a freshness pass.

Grade log

Every change to a grade, dated, with the reason and what would move it again. Grades are dated judgements, not permanent facts, and this is the audit trail for them.

  1. DihexaE → D

    Corrected an inconsistency between surfaces: some carried E, others D. D is correct under the published rubric. Dihexa's evidence is preclinical, with human data essentially absent — which is what D describes: animal and lab evidence, human trials still to come. E is reserved for compounds whose marketing claims outrun the data, which is a different measurement and does not apply here.

    What would change it: Published placebo-controlled human efficacy data.

Maintained by the Peptós.LIFE editorial team · Last updated June 2026. Educational content, not medical advice. Compounded medications are not FDA-approved.
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