The five questions to ask of any peptide study
- Who or what was studied? Humans, animals, or cells. Then: how many, how old, how healthy, and how similar to you.
- Was there a control group, and was allocation random and blinded? Uncontrolled studies cannot separate the treatment from time, placebo effects and regression to the mean.
- What was the primary outcome, and was it prespecified? A study that measures twenty things and reports the three that moved is not evidence.
- How big was the effect, with what uncertainty? "Statistically significant" can describe a trivial change; look for confidence intervals and absolute differences.
- Who paid, and has anyone replicated it? Industry funding does not invalidate a result but raises the bar for independent confirmation.
The animal-to-human gap
Rodent studies are essential for mechanism and early safety, but their translation rate to human efficacy is poor across medicine — and worse for regenerative and neurological outcomes than for, say, antibiotics. Animal models are young, genetically uniform, and injured deliberately in ways that rarely match human disease. When a peptide's evidence is entirely animal, the honest statement is "we do not know whether this works in people".
How marketing misuses real papers
- Citing a rat study under a headline about human healing.
- Quoting a mechanism ("increases growth hormone") as if it were an outcome ("builds muscle").
- Presenting a case report or a single open-label study as proof.
- Describing decades of publications from one lab as a "large body of evidence".
- Conflating "not FDA-approved" with "FDA hasn't gotten around to it" rather than "no adequate trials exist".
Our explainers linked below go through each of these with worked examples from the peptide literature.