Peptide Tier List 2026: 305 peptides ranked S to F
Every peptide on the site, ranked. A holistic editorial verdict that combines evidence strength, human data, effect size, and real-world adoption.
Last updated ·A research-evidence ranking, not medical advice
How the tiers work
Every peptide gets one tier, S through F, based on four criteria: the strength of the overall evidence, how much of it comes from human studies, how large and repeatable the effect is, and how widely the peptide is used in the real world. Within a tier, peptides are ordered by popularity.
- S-Tier · 4 peptidesEstablished. Multiple human RCTs, large effect, high adoption.
- A-Tier · 25 peptidesStrong. Solid human data with a clear, reproducible effect.
- B-Tier · 106 peptidesPromising. Moderate human data with consistent preclinical support.
- C-Tier · 76 peptidesMixed. Early human data; effect size or consistency uncertain.
- D-Tier · 87 peptidesPreliminary. Mostly preclinical with little or no human evidence.
- F-Tier · 7 peptidesBelow grade. Minimal evidence or weak/no demonstrated effect.
S-tier peptides right now: Semaglutide, Tirzepatide, Somatropin, and Insulin — 4 of 305 peptides on the list.
Tier is not the same as evidence level. Evidence level is mechanical: it measures how much research exists. Tier is the harder editorial call. It weighs that evidence against effect size, the depth of human data specifically, and how consistently real-world use mirrors the trial outcomes. A peptide can have moderate evidence and still land at A-tier if the human signal is unambiguous and the effect is clinically meaningful. Another can have a stack of preclinical papers and stall at C because nothing translates.
A tier is a research-evidence ranking, not a personal treatment recommendation. An S-tier peptide is not automatically right for you, and an F-tier one is not necessarily dangerous; safety is rated separately on each profile. This list is for educational purposes only. Talk to a qualified healthcare provider before starting, stopping, or changing any treatment.
All 305 peptides by tier
Hover any peptide for its popularity and evidence level; click to open the full profile with citations.
S-Tier peptides
4 peptidesReserved for peptides with multiple human randomized trials, a clearly demonstrated effect that replicates across studies, and broad real-world adoption — typically with FDA approval or extensive off-label clinical use. These are the peptides where the evidence is overwhelming and the effect size is hard to argue with.
A-Tier peptides
25 peptidesStrong human data with a clear, reproducible effect. Either approved abroad, in late-stage trials, or with such consistent published support that the mechanism and outcome are well-mapped. Real-world adoption is solid; the open questions are dose optimization and long-term safety, not whether the thing works.
B-Tier peptides
106 peptidesPromising. Some human data, often a phase II or open-label study, paired with consistent preclinical work. The signal is real but the effect size or duration is less certain than tier A. Most peptides at this grade are watched with cautious optimism — they may climb to A as more data lands.
C-Tier peptides
76 peptidesMixed. Early human data exists but the effect is inconsistent, or the trials are small / underpowered. Mechanism is plausible. Real-world reports vary widely. These are reasonable candidates to follow if you have a specific use case the research touches on, but the evidence is not yet decisive.
D-Tier peptides
87 peptidesPreliminary. Mostly animal and mechanistic work, with little to no controlled human evidence. People discuss them based on theory or anecdote. We list them because they are part of the conversation, not because the data supports broad use.
F-Tier peptides
7 peptidesBelow grade. Either the evidence is essentially absent, the proposed effect doesn't replicate, or the marketing has run far ahead of the science. We keep these listed for completeness and so visitors can see why they don't belong on a serious shortlist.
Frequently asked questions
What are S-tier peptides?
S-tier is reserved for peptides with multiple human randomized controlled trials, a large effect that replicates across studies, and broad real-world adoption. 4 of the 305 peptides on the list make S-tier right now: Semaglutide, Tirzepatide, Somatropin, and Insulin. A-tier, the next rung down, holds 25 peptides with solid human data and a clear, reproducible effect.
How are peptides ranked?
Each peptide gets one holistic tier from S to F based on four criteria: evidence strength, the depth of human data, effect size, and real-world adoption. S means established, A strong, B promising, C mixed, D preliminary, and F below grade. The current spread is 4 S-tier, 25 A-tier, 106 B-tier, 76 C-tier, 87 D-tier, and 7 F-tier. Within a tier, peptides are ordered by popularity. The tier is an editorial call, separate from the mechanical evidence grade, which only measures how much research exists.
Is a higher tier a recommendation?
No. A tier ranks the strength of the research and the real-world track record, not whether a peptide is right for you. Safety is rated separately on each profile, and an S-tier peptide can still be a poor fit because of your health history, other medications, or goals. This list is for educational purposes only. Talk to a qualified healthcare provider before starting, stopping, or changing any treatment.
How often is the tier list updated?
There is no fixed yearly refresh. Each peptide's tier lives on its profile, and this page is rebuilt from those profiles every time the site is published, so a re-grade shows up here as soon as it ships. Tiers move when new human trial results, regulatory decisions, or safety findings change the picture. The most recent profile update was November 6, 2026.
See something you'd rank differently? The tier list reflects our reading of the literature as of November 6, 2026 and will move as new data is published. Each peptide page links to the underlying citations so you can audit the call.