The one rule
Tiers rank the strength of published evidence, never effectiveness, safety, popularity or value. A tier-S peptide is not “better” than a tier-C one; it has simply been tested more rigorously in humans and reviewed by a regulator. We assign each entry the tier of the strongest rung it has reached on the evidence ladder.
Tier definitions
Tier S · Approved 8 entries
Approved by the FDA or EMA for at least one indication.
The FDA (United States) or the EMA (European Union) has approved a product containing it for at least one indication. Approval is the strongest public signal that controlled evidence has been independently reviewed. A past approval still counts if the product was later discontinued for commercial reasons.
Tier A · Controlled human trials 17 entries
At least one published randomized controlled trial in humans.
No FDA/EMA approval, but at least one randomised controlled trial in humans has been published. One RCT is enough to qualify; it does not need to have been positive, and the trial may concern a different use from the one people discuss online.
Tier B · Small human studies 7 entries
Human data limited to small, open-label or pharmacokinetic studies.
Human data exist but are limited to small, open-label, pilot or pharmacokinetic studies — no published randomised controlled trial.
Tier C · Animal data 15 entries
Evidence comes mostly from animal studies.
Evidence comes predominantly from animal (in vivo) studies, with little or no published human data.
Tier D · Lab / anecdote 0 entries
Cell studies only, or almost nothing published.
Only cell (in vitro) studies, or almost nothing published at all.
Approvals outside the US and EU
Some peptides are approved medicines in other countries — several were developed and registered in Russia, for example — but have never been approved by the FDA or EMA. Those approvals do not earn tier S. We hold the top tier to two large regulators whose review documents are publicly accessible, so the tier means the same thing for every entry. A peptide approved elsewhere is ranked on its published trial evidence like everything else, and each entry lists its other approvals separately.
Examples in the library: GHRP-2 (tier B) , Semax (tier B) , Selank (tier A) , Cerebrolysin (tier A) .
Why combos are unranked
Blends such as “Wolverine stack” are sold as single products, but the combinations themselves have essentially no published studies. Giving a blend its strongest component’s tier would overstate the evidence, so the library’s 9 combos carry no tier. Each combo page links to its components, which are ranked individually.
How tiers change
A tier moves only when the published record moves:
- Up when a qualifying study is published (for example, a first human RCT moves a tier-B peptide to A) or when the FDA or EMA grants an approval.
- Down when the evidence a tier rested on is retracted, or when an approval is withdrawn for reasons of safety or efficacy.
- Revised when we find we misread or missed a source. Corrections are welcome.
Every change is logged in the patch notes with ▲ and ▼ markers. Rationale for each tier is written on the entry page together with the sources it relies on.
What tiers do not mean
- Not a recommendation. Nothing here suggests anyone should use any substance.
- Not a safety rating. Approved drugs have known side effects; unstudied compounds have unknown ones.
- Not proof for every claim. An approval or RCT covers a specific use, population and formulation. Benefits claimed for other uses may be untested.
- Not a statement about products on the market. Grey-market vials labelled with a peptide’s name may not contain what the label says. Evidence for a molecule says nothing about any particular product.
- Not a measure of effect size. A peptide with an RCT showing a tiny effect and one showing a large effect sit in the same tier.