Peptide Evidence-Grade Index
18commonly discussed peptides, graded A–D by one thing only: how much rigorous human clinical evidence exists — not how heavily they are marketed. A high grade means “well-studied,” never “proven to work for you.”
Built and medically reviewed by Charles Kamen, MD, board-certified neurologist ·
Of 18 commonly discussed peptides, only 5 are FDA-approved with multiple Phase 3 trials (semaglutide, tirzepatide, liraglutide, tesamorelin, and bremelanotide) — while several of the most heavily marketed, including BPC-157, epithalon, and MOTS-c, have zero completed human efficacy trials. This index grades only the strength and quantity of human clinical evidence for each peptide. It is an evidence-cartography tool, not a treatment guide: a high tier means a molecule has been studied in well-designed human trials, not that it is effective for what it is marketed for. “Studied for” describes the research question a trial asked — never an outcome.
The grading rubric
Each peptide is graded by the highest level of completed human evidence that exists for it — regardless of how popular or heavily marketed it is.
FDA-approved for at least one indication, supported by multiple completed Phase 3 randomized controlled trials. The gold standard of human evidence.
Not FDA-approved for the use in question, but has one or more completed human RCTs in the peer-reviewed literature — or is approved abroad / for a narrow historic indication on RCT data.
Human data exists but is limited to pilot trials, small or early-phase studies, observational cohorts, or non-blinded programs. Clinical outcomes are not robustly established.
Evidence is animal or laboratory only. No completed registered human trial demonstrating clinical outcomes — even if early-phase human trials are now registered or recruiting.
Tie-breaker: a peptide is graded by its strongest completed human evidence for a defined clinical question. A registered-but-not-completed trial does not lift a peptide out of Tier D — recruitment is not evidence.
The index
| Peptide | Tier | ~Completed human trials | Studied for (neutral) | Evidence note |
|---|---|---|---|---|
| Semaglutide (Ozempic / Wegovy) | A | Dozens of Phase 3 RCTs (STEP, SUSTAIN, PIONEER) | Type 2 diabetes; chronic weight management; cardiovascular risk | Among the most extensively trialed peptides in medicine; FDA-approved 2017 (diabetes), 2021 (weight). |
| Tirzepatide (Mounjaro / Zepbound) | A | Dozens of Phase 3 RCTs (SURPASS, SURMOUNT) | Type 2 diabetes; chronic weight management; obstructive sleep apnea | Dual GIP/GLP-1 agonist; FDA-approved 2022 (diabetes), 2023 (weight), 2024 (OSA). |
| Liraglutide (Victoza / Saxenda) | A | Multiple Phase 3 RCTs (SCALE; LEADER outcomes) | Type 2 diabetes; chronic weight management; cardiovascular risk | First daily GLP-1; FDA-approved 2010 (diabetes), 2014 (weight); now has generics. |
| Tesamorelin (Egrifta) | A | 2 pivotal Phase 3 RCTs | Reduction of excess visceral abdominal fat in HIV-associated lipodystrophy | GHRH analog; FDA-approved 2010 — the only FDA-approved growth-hormone-releasing peptide. Narrow indication, but multi-RCT. |
| Bremelanotide / PT-141 (Vyleesi) | A | 2 pivotal Phase 3 RCTs (RECONNECT 1 & 2) | Acquired, generalized HSDD in premenopausal women | Melanocortin-4 agonist; FDA-approved 2019. The consumer "PT-141" sold for general libido use is off-label / non-FDA-approved. |
| Thymosin alpha-1 (Zadaxin) | B | 30+ human trials incl. multiple RCTs | Hepatitis B & C (adjunct); immune modulation; sepsis (investigational) | Approved in 35+ countries but never FDA-approved in the U.S. Unusually large RCT base for a non-U.S.-approved peptide. |
| Retatrutide | B | Multiple Phase 3 RCTs completed/reporting (TRIUMPH) | Chronic weight management; type 2 diabetes; cardiometabolic risk | Triple GLP-1/GIP/glucagon agonist. Strong Phase 3 data, but investigational — not yet FDA-approved as of June 2026 (NDA anticipated later in 2026). |
| TB-500 / Thymosin beta-4 | C | A few small trials — for the topical drug RGN-259, not consumer "TB-500" | Wound/tissue repair; dry eye; neurotrophic keratopathy | Critical distinction: human trials used RGN-259, a topical ophthalmic Tβ4 drug — not the injectable "TB-500" sold to consumers, which has no completed human efficacy trials. A 2024 Phase 3 dry-eye program missed its primary endpoint. |
| CJC-1295 | C | ~1 early-phase human PK/PD RCT | Short-term growth-hormone / IGF-1 secretion (pharmacodynamics) | Human data confirms it raises GH/IGF-1 short-term; no completed clinical-outcome trials. The one outcome trial registered was terminated. |
| Ipamorelin | C | ~1–2 small early-phase human studies | Growth-hormone secretion (pharmacodynamics) | Early human data shows GH secretion; no completed outcome trials. There are zero rigorous human trials of the popular CJC-1295 + ipamorelin combination. |
| Sermorelin (formerly Geref) | C | Small therapeutic & GHRH studies | Historic: pediatric growth-hormone-deficiency diagnosis & treatment | Was FDA-approved, discontinued 2008 for business — not safety — reasons. Current adult/anti-aging use is off-label via compounding; no large modern RCTs for those uses. |
| GHK-Cu (copper tripeptide) | C | ~7 human studies, ~1–2 RCTs | Topical: skin appearance / photoaging; wound healing | A topical human signal exists, but landmark cosmetic trials were industry-sponsored and largely conference-presented; results are mixed. Not in major wound-care guidelines. |
| Semax | C | Multiple Russian clinical trials | Ischemic stroke adjunct; cognition; neuroprotection (as studied in Russia) | Regulatory-approved in Russia for stroke/encephalopathy. Evidence is concentrated in Russian institutions and largely not independently replicated in Western RCTs; not FDA-approved. |
| Selank | C | Russian Phase 3-level trials | Anxiety / generalized anxiety disorder (as studied in Russia) | Approved in Russia as an anxiolytic. Minimal English-language peer-reviewed RCT data; not FDA-approved. |
| MOTS-c | D | 0 completed outcome trials; Phase 1/2 registered & ongoing | Insulin sensitivity; metabolic health; exercise-related metabolism | Strong animal and human-observational data, but no completed human efficacy trial. A Phase 2a in prediabetes is underway, not finished. Registration is not completed evidence. |
| BPC-157 | D | 0 completed registered human efficacy trials | Tissue/tendon/muscle healing; gut protection (preclinical questions) | Despite very heavy marketing, BPC-157’s evidence is almost entirely animal/in-vitro. The 2015 Phase 1 was cancelled without results; a 2025 hamstring trial is registered but not completed. Not FDA-approved. |
| Epithalon / Epitalon | D | 0 trials registered on ClinicalTrials.gov | Aging biomarkers; telomere biology; pineal/longevity research | An in-vitro telomerase signal exists in human cell cultures. Human "longevity" claims trace to non-blinded, non-randomized Russian observational programs, often using the extract Epithalamin rather than synthetic Epitalon. |
| NAD+ / NMN (non-peptide contrast) | C | ~8–9 completed human RCTs (small, early-phase) | NAD+ metabolism; insulin sensitivity; muscle function; healthy aging | Included as a non-peptide contrast. Human trials confirm NMN raises blood NAD+ levels and is well tolerated; clinical-outcome evidence is preliminary. A dietary supplement, not an FDA-approved drug. |
How this index is built: compiled and reviewed by Charles Kamen, MDfrom ClinicalTrials.gov, PubMed / PubMed Central, and U.S. FDA records. Trial counts are approximate and reflect a point-in-time read of public registries (June 2026); the tiers are firm, the exact counts carry the uncertainty. The row for systemic “TB-500” is consolidated into the thymosin beta-4 entry, since they are the same/overlapping molecule — this keeps the index honest rather than padding the count.
Scope & compliance:this index grades how much human evidence exists, never whether a peptide “works,” is safe for you, or is right for any condition. It contains no doses, no titration schedules, no patient outcomes, and no protocols. Many peptides here are not FDA-approved. This is educational information about the state of clinical research — not medical advice. Decisions about any peptide should be made with a licensed physician who can evaluate your individual situation.
Peptide Evidence FAQ
Does BPC-157 have human clinical trials?
As of June 2026, BPC-157 has no completed registered human efficacy trials on ClinicalTrials.gov. A 2015 Phase 1 safety trial was cancelled without published results, and a 2025 hamstring-strain trial is registered but not yet completed. Essentially all BPC-157 evidence to date is from animal and laboratory studies — which is why it is graded Tier D (preclinical only) in this index.
Which peptides have the strongest human evidence?
The GLP-1-class and incretin peptides — semaglutide, tirzepatide, and liraglutide — have the strongest human evidence, each backed by dozens of completed Phase 3 randomized controlled trials and FDA approval (all Tier A). Tesamorelin and bremelanotide are also Tier A, but for narrow, specific FDA-approved indications.
Are peptides like sermorelin, CJC-1295, and ipamorelin FDA-approved?
No. Sermorelin was historically FDA-approved for a pediatric use but was discontinued in 2008 for business reasons and is now used off-label via compounding. CJC-1295 and ipamorelin have never been FDA-approved; their human data is limited to small early-phase studies showing growth-hormone elevation, and there are no rigorous human trials of the popular combination. All three are graded Tier C.
Does "studied for" mean a peptide is effective for that?
No. "Studied for" means a clinical trial asked a research question about that topic — it is not a statement that the peptide works, is safe for you, or is approved for that use. This index grades how much human evidence exists, never whether a peptide is effective. Always consult a licensed physician.
Is thymosin alpha-1 FDA-approved?
No. Thymosin alpha-1 (Zadaxin) is approved in more than 35 countries and has an unusually large clinical-trial base, but it has never received FDA marketing approval in the United States. It is graded Tier B.
Is there human evidence for "anti-aging" peptides like epithalon or MOTS-c?
Both are graded Tier D (preclinical only) in this index. MOTS-c has strong animal data and is now in early human trials, but no completed human efficacy trial. Epithalon has no ClinicalTrials.gov registrations; its human data is older, non-blinded Russian observational work. Neither is FDA-approved.
Related reading: Which peptides are FDA-approved? · FDA peptide compounding status tracker · Is peptide therapy safe?
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