Mechanisms, pharmacology and the evidence-grading methodology behind the site.
The Science explains how peptides work and how we judge the evidence about them — receptor mechanisms, pharmacokinetics and pharmacodynamics, routes and chemistry, and the peptide classes — plus the evidence-grading methodology that underpins every claim on the site. It is the transparency layer: the rules we follow so a reader can trust the grades.
A functional taxonomy of therapeutic and research peptides — 11 classes mapped by molecular target, representative molecules, and evidence maturity, from Grade-A approved drugs to Grade-D marketing claims.
A clinical explainer separating true peptides from the SARMs, small-molecule drugs, hormones, and supplements sold beside them on the same gray-market storefronts. Chemistry, evidence, FDA status, and anti-doping rules are all class-specific.
The ScienceThe trust cornerstone of PeptideVox — how we assign an A-to-D evidence grade to every peptide claim, anchored to GRADE, the Oxford CEBM levels, USPSTF, and Cochrane RoB 2, and why human evidence is never blended with animal, in-vitro, or anecdotal data.
A peptide is a short chain of amino acids — the same building blocks that make proteins, but far smaller, typically from a few up to around fifty residues. Peptides act as signaling molecules: they bind specific receptors to trigger biological effects, which is why they are studied for everything from tissue repair to metabolism to cognition. They differ from small-molecule drugs (which are simpler chemicals) and from full proteins (which are much larger), and that middle position shapes their pharmacology, stability and how they must be administered.
We use a fixed A-D scheme. Grade A requires human randomized controlled trials or meta-analyses; grade B is lower-tier human evidence (cohort, observational, open-label); grade C is preclinical only (animal or in-vitro); grade D is anecdotal, mechanistic-only or marketing claims. The grade is assigned to the specific claim, with one best citation, and inherited consistently across the monograph, any listicle and the master comparison table. Grading is conservative — when human and preclinical evidence conflict, the claim is graded down to the human-evidence level.
Most peptides are fragile and poorly absorbed, so how they are given changes whether they work at all. Many are degraded in the gut, which is why injectable (subcutaneous or intramuscular) routes dominate; a few, like BPC-157, are reported to be unusually stable and are used orally for gut indications. Intranasal routes are common for brain-targeted peptides. Pharmacokinetics — half-life, bioavailability, distribution — varies enormously by peptide and route, and we report the human data where it exists and flag where only animal data are available.
The majority of compounds documented here are not approved by the FDA for human use. Approved drugs (e.g. semaglutide, tirzepatide) are noted explicitly and require a licensed prescriber.
Many peptides — including BPC-157 and GHK-Cu in injectable form — are sold strictly "for research use only — not for human consumption." Purity, identity, and dosing of such products are not regulated or guaranteed.
Several compounds are banned in competitive sport under the WADA Prohibited List. Athletes risk sanction regardless of intent or formulation.
Always consult a qualified, licensed healthcare professional before considering any compound. Individual risk depends on your full medical context.
This content is for informational and educational purposes only · No physician–patient relationship is created · Evidence grades reflect published data as of the stated revision and may change.
