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Peptide Reference

Methodology and the A to D grading scale

How this site grades peptide evidence: four letters for the kind of human evidence that exists, one flag for a published FDA safety concern, and the rules for what counts, what does not, and why a negative trial and a positive one can share a letter.

By FormBlends editorial teamUpdated September 4, 2026Educational, not medical advice

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Result

Type a name or pick an entry. The result shows the evidence grade, what the grade applies to, the FDA and PCAC status, safety signals on record, and the human studies with PubMed ids.

Across the reference: 3 graded A, 1 graded B, 5 graded C, 6 graded D, and 10 carry the X flag for a published FDA safety concern.

Peptide marketing runs on a single rhetorical move: describe a mechanism, cite a rat study, and let the reader assume a human result. This scale exists to interrupt that move. It asks one narrow question of every substance: what kind of evidence in humans exists for the use people ask about?

The scale

A. Approved product with labelling. An FDA-approved product exists for the graded use. That means FDA reviewed the trials, the label states adverse-reaction rates from those trials, and the storage, dose and warnings are written down by someone accountable for them. Two substances on this site qualify: tesamorelin and bremelanotide, plus the GLP-1 peptides by pointer.

B. Multiple randomised controlled trials. Two or more RCTs in humans for the graded use, published in peer-reviewed journals, with no currently marketed approved product. Sermorelin sits here: randomised comparisons against growth hormone in children, and a product that was approved and later discontinued.

C. One RCT, or only small controlled studies. Either a single randomised controlled trial, or human studies with a concurrent control group that fall short of a full RCT: a placebo-controlled phase 1 dose study, a randomised active-comparator study without placebo, a controlled but non-randomised comparison. CJC-1295, ipamorelin, semax, selank and epitalon sit here, with very different confidence within the tier, which the pages spell out.

D. No controlled human study. The evidence is animal or cell work, observational measurements in humans, or human reports without a control group: case series, retrospective chart reviews, open-label pilots. BPC-157, TB-500, MOTS-c, injectable GHK-Cu, injected NAD+ and AOD-9604 sit here.

X. FDA safety concern published. Added to any grade when FDA has published a specific safety concern for the substance in compounding, on its Category 2 page under section 503A or 503B, whether the substance is currently listed or shown as nominated but withdrawn, or when an approved product carries a warning of similar weight. Ten of the fourteen substances carry it.

What the grade applies to

Every grade is tied to a stated use, shown on the page as "graded for." Tesamorelin is A for excess abdominal fat in HIV-associated lipodystrophy, because that is what the trials tested and the label covers. It is not A for fat loss in a healthy 50-year-old; that use has no trial and no grade. Sermorelin is B for growth hormone deficiency in children, not for adult "optimisation." When a page says a use is "not graded," that is the answer: nobody has done the study.

What counts and what does not

  • Counted: interventional human studies of the substance itself, indexed in PubMed, in any language, with the design stated.
  • Shown but not counted: studies of a related molecule. Full-length thymosin beta-4 for TB-500, oral nicotinamide riboside for NAD+, the epithalamin extract for epitalon. These appear in the tables with a "related molecule" note so you can see what sales pages are substituting.
  • Not counted: press releases, conference abstracts without a paper, company announcements of unpublished trials, testimonials, and mechanism papers in animals or cells. They are mentioned where they explain a claim, and given no weight.
  • Regulatory status is separate from the grade. NAD+ is in FDA's Category 1 and graded D. Ipamorelin is in Category 2 and graded C. One axis is enforcement policy, the other is evidence. Both are shown.

Where the numbers come from

Trial designs and results come from the PubMed abstract or full text, cited by PubMed id on every row. Regulatory status comes from FDA's 503A bulks page and its category list document (dated May 14, 2026), the Category 2 safety page (dated April 22, 2026), the Pharmacy Compounding Advisory Committee meeting pages, Drugs@FDA and DailyMed. FDA pages carry a "content current as of" date; we quote it. When FDA changes a page, the status changes and the updated date on ours moves.

We searched PubMed on September 4, 2026 using each substance's name and its common aliases, with and without the "humans" filter, and read the abstracts of everything returned. A study count of zero means we found none, not that none can exist; if you know of one, the about page says how to tell us.

What this site deliberately leaves out

No doses for any substance graded B, C or D. No instructions for reconstituting, drawing up or injecting anything except by reference to an FDA label for an approved product. No links to sellers. No testimonials, no named clinicians, no star ratings. FDA treats the combination of dosing content, reconstitution instructions and a purchase link as evidence that a product is intended for human use as a drug, and for the substances graded D that is precisely the claim the evidence does not support. Our reasons are set out in why peptide stacks fail evidence standards.

Limits

The scale is coarse by design. It does not weigh sample size, blinding quality, sponsor independence or publication bias within a tier; the pages do that in prose. It is a filing system for a question most peptide pages refuse to ask, and it should be read alongside the page it labels.

Questions people ask

Is a higher grade a recommendation?

No. The grade describes what kind of human evidence exists for a stated use. Tesamorelin is A for HIV-associated lipodystrophy and ungraded for anything else. Ipamorelin is C because a randomised trial exists, and that trial was negative. Read the page, not the letter.

Why does a negative trial count the same as a positive one?

Because the scale measures the strength of the evidence base, not the direction of the result. A completed randomised trial tells you far more about a compound than a hundred rat studies, whichever way it came out. The result is reported on the page in the same table as the design.

Why is the X flag applied to substances FDA has 'withdrawn' from Category 2?

Because FDA keeps the safety concern on its page after the nomination is withdrawn. Withdrawal changes the substance's procedural status; it does not retract FDA's stated concern. When FDA removes the concern, we remove the flag.

Sources

  1. FDA: Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks (content current as of April 22, 2026) Accessed September 4, 2026.
  2. FDA: Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act Accessed September 4, 2026.
  3. Shankar G et al. Assessment and reporting of the clinical immunogenicity of therapeutic proteins and peptides: harmonized terminology and tactical recommendations. AAPS J 2014. PubMed 24764037 Accessed September 4, 2026.
  4. PubMed (National Library of Medicine), searched September 4, 2026 Accessed September 4, 2026.

Canonical URL: https://formblendspeptides.com/guides/methodology-and-grading-scale. Written by the FormBlends editorial team. This page is educational and is not medical advice; see the medical disclaimer.