Reading the evidence
Most peptide claims rest on animal studies. Here is the grading system we use, what each grade means, and how to tell data from marketing.
MaxHuman Editorial
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The hardest part of researching peptides is not finding information. It is working out how much weight any given claim can carry. A finding in eight rats and a finding in a randomised trial of two thousand adults are both "studies", and they are routinely quoted the same way.
So we grade every claim on this site by the strength of the evidence behind it, and we show the grade next to the claim.
The grades
Grade A — multiple human randomised controlled trials, or a systematic review of them. The strongest position an effect can be in.
Grade B — at least one human randomised controlled trial, or consistent controlled human studies. Stated cautiously.
Grade C — small, uncontrolled, or observational human data only. Described as limited or early.
Grade D — mechanistic, animal, or in-vitro work only, with no human data. We describe what was observed and in what model, and nothing beyond that.
Grade X — studies disagree, or the claim is not supported by the sources found. Both sides get stated, or the claim does not stand.
Why most peptide claims are Grade D
This is the part most sites will not tell you. For the majority of compounds discussed in this space, the published work is preclinical — cell cultures and rodents. That is genuine science, and it is how research starts. It is also not evidence that something works in a human being.
The gap is not a formality. Compounds routinely show an effect in a rodent model and no effect in people, or an effect at a dose that does not translate, or an effect alongside harms that only appear in longer human studies. A Grade D claim is a reason to be curious, not a reason to be confident.
Reading a study without a science degree
Four questions get you most of the way:
Was it in humans? If the abstract says mice, rats, or cells, nothing about human outcomes follows from it.
Was there a control group? Without one, you cannot separate the compound from time, placebo, or everything else the participants changed.
How many people? A finding in twelve participants is a signal to investigate, not a conclusion.
Who funded it? Industry funding does not make a study wrong, but it belongs in your assessment. In this field it is common.
Marketing tells you can learn to spot
Before-and-after photographs, which are not evidence of anything.
Personal testimonials used in place of data.
Language implying regulatory endorsement — "proven in the clinic", "doctor-approved" — none of which are recognised regulatory categories.
A mechanism described as though it were an outcome — "activates the pathway" is not "improves the condition".
A confident number with no citation behind it.
What a grade is not
A strong grade means the evidence is strong. It does not mean the compound is appropriate for you, and it does not mean the effect is desirable — a well-evidenced finding can describe a harm. Evidence strength and personal suitability are separate questions, and the second one belongs with a professional who knows your history.
This is educational information, not medical advice, and not a substitute for a qualified healthcare professional. Nothing here recommends a dose or a compound.