Every peptide.Every study.Graded.
An evidence-graded reference for every peptide in the scientific literature. Letter grades for each peptide × outcome, every claim linked to its source paper. Open-source grading scale — every calculation shown.
Peptides graded
40
Studies indexed
494
Outcomes graded
210
Rubric
Public
PEPTIDE_NAME
Semaglutide
GLP-1 receptor agonist
// OUTCOME: TYPE 2 DIABETES
Phase 3 trials showed a 14.9% mean weight loss at 68 weeks — vs 2.4% on placebo.
SUB-SCORES
Studies
312
Outcomes
9
Yrs post-mkt
8+
§ 01.00
BROWSE_BY_USE
Find peptides by what they do.
87 peptides organized across 8 therapeutic categories. The grade badge shows the strongest-evidence peptide in each category.
Metabolic & Weight
GLP-1 family, amylin agonists, incretin combinations for diabetes, obesity, metabolic syndrome.
Recovery & Repair
Tissue repair, tendon healing, gut integrity, post-injury peptides. Predominantly preclinical; no A-grade human trial.
Growth Hormone Axis
GH secretagogues and IGF modulators for body composition, sleep, aging biomarkers.
Longevity & Aging
Peptides claimed to extend healthspan or lifespan. Most evidence is animal-only or single-lab.
Sexual Health
Melanocortin agonists and PT-family peptides for sexual desire and dysfunction.
Immune & Infection
Thymic and antimicrobial peptides for immune modulation, viral infection, post-infection recovery.
Cognitive & Mood
Nootropic peptides for memory, anxiety, focus, neuroprotection — primarily Russian literature.
Skin & Hair
Topical and injectable peptides for collagen synthesis, pigmentation, hair growth. Mostly cosmetic-grade data.
§ 02.00
THE_METHOD
How we grade. In public.
Each peptide receives an evidence grade for every outcome it has been studied for — not a single blanket score. The rubric is open-source: six sub-scores, weighted, rolled into a letter. Every calculation is shown on the peptide page. BPC-157 grades C for tendon healing and C for IBD on different evidence bases. We grade the evidence, not the molecule.
Strong
Multiple high-quality human RCTs converge. Mechanism understood. Long-term safety data exists. Effect clearly exceeds placebo.
Promising
At least one well-powered human trial showing benefit. Mechanism plausible. Limited long-term data.
Mixed
Conflicting human results, small samples, or strong animal data without human confirmation.
Weak
Animal-only or anecdotal evidence. Mechanism speculative. No meaningful human data.
Unsafe / Disproven
Human data shows no effect, harm, or unacceptable risk. Or banned by major regulatory body.
01
Mechanism understood
02
Human studies (count + quality)
03
Effect vs placebo
04
Long-term safety data
05
Side effect profile
06
Regulatory status
§ 03.00
FEATURED_THIS_EDITION
Four peptides, four grades.
Semaglutide
GLP-1 receptor agonist
OUTCOME: TYPE 2 DIABETES
Multiple high-powered RCTs converge, mechanism is well-understood, FDA-approved, long-term safety data out to 4+ years.
Studies
312
Outcomes
9
Yrs post-mkt
8+
Tirzepatide
Dual GIP / GLP-1 agonist
OUTCOME: OBESITY
Well-powered Phase 3 program, dual receptor mechanism characterized, FDA-approved with active surveillance.
Studies
198
Outcomes
7
Effect
Δ20.9%
BPC-157
Body protective compound 157
OUTCOME: TENDON HEALING
Animal evidence is consistent, but human evidence is limited to three uncontrolled pilots (~26 subjects total).
Studies
154
Outcomes
7
Human RCTs
0
GHK-Cu
Copper tripeptide-1
OUTCOME: WOUND HEALING
Mechanism partially understood, topical evidence is decent, but injectable claims outrun the data.
Studies
87
Outcomes
5
Topical RCTs
9
§ 04.00
RESEARCH_FEED
The week in peptide research.
150+ studies summarized monthly. Members get the full breakdown, methodology critique, and effect-size context.
Retatrutide
Obesity
At 48 weeks, 12 mg dose produced a mean placebo-adjusted body weight reduction of 22.1%. Effect appears to plateau at 36 weeks in the high-dose arm.
NEJM · n=338BPC-157
Achilles tendinopathy
Subcutaneous BPC-157 (250 mcg BID, 4 weeks) reduced VISA-A pain scores vs baseline. No control arm. Findings hypothesis-generating only.
J Sports Med (preprint) · n=22Cagrilintide + semaglutide
Weight loss
Combination outperformed semaglutide monotherapy by 5.3 percentage points in mean weight loss at 68 weeks, comparable GI side-effect profile.
Lancet · n=1247Epitalon
Lifespan extension
No human RCTs identified. Animal lifespan data limited to single-lab Russian-language publications, with methodological concerns and no replication.
Ageing Res Rev§ 05.00
EDITORIAL_STANDARDS
The four principles.
Not aspirations. The test we apply to every page before it ships.
Shown
Every grade ships with its calculation. Sub-scores, weights, weighted total, the band that total lands in — published on every peptide page. Check our work, challenge the math.
Cited
Every claim links to a primary source by DOI or PubMed ID. If we can't cite it, we don't claim it.
Honest about gaps
Every peptide page includes a required "What we don't know yet" section. Absence of evidence is information.
Outcome-specific
Grades attach to peptide × outcome pairs. A molecule can be A for one use and D for another.
§ 06.00
COMMON_QUESTIONS
The questions we get most.
Q01What is a peptide?
A peptide is a short chain of amino acids — the same building blocks that make up proteins, just in a smaller sequence (typically 2 to 50 amino acids). Many peptides are signaling molecules the body produces naturally; others are synthetic analogs designed to mimic, block, or modify those signals.
Q02How does Peptigrade assign grades?
Each peptide is graded against six weighted sub-scores for every outcome: mechanism understood, count and quality of human studies, effect vs placebo, long-term safety data, side effect profile, regulatory status. Sub-scores roll up into a letter grade A–F.
Q03How do I know the grades aren't rigged?
Our grading rubric is open-source. Every calculation — the six sub-scores, how they're weighted, the evidence thresholds that gate each letter — is published on the Methodology page and on every peptide's grade breakdown. If a grade looks wrong, you can audit exactly how we got there and tell us where to re-check. See the full rubric at /methodology.
Q04Are these peptides legal?
It depends on the peptide and the jurisdiction. Some are FDA-approved drugs. Some are sold legally for research use only. Some are banned in competitive sports by WADA. Each peptide page includes its current regulatory status.
Q05Why does the same peptide get different grades for different uses?
Because the evidence is different for each use. BPC-157 has strong animal evidence for tendon healing but no randomized human trial — that earns a C. Semaglutide has ten Phase 3 RCTs for type 2 diabetes — that earns an A.
Q06How often are grades updated?
Whenever new high-quality evidence is published. We monitor PubMed, ClinicalTrials.gov, and major journals for new peptide studies. When a new RCT or systematic review materially changes the evidence base, we re-grade the page.
Q07Is this medical advice?
No. Peptigrade publishes evidence summaries for educational purposes. Nothing on this site recommends that any specific person take any specific peptide. Consult a licensed medical professional before making any health decision.