Peptide tier list 2026: the best-studied peptides, ranked by evidence

How the tiers work

Most peptide tier lists rank compounds by reputation, anecdotes or how popular they are. This one ranks only the evidence: how much published research in people exists, and whether a regulator has reviewed it. A compound moves up a tier when that evidence changes, not when it becomes more popular.

• Tier S, fda-approved. Approved by the FDA for at least one specific indication.
• Tier A, strong human trials. Randomized human trials published in major journals, or a former FDA approval, but not currently approved.
• Tier B, some human evidence. Human studies or approvals outside the US exist, but the evidence is smaller, older, regional or mixed.
• Tier C, early human data. Pharmacokinetic, pilot or safety studies in people; the effects people talk about come mostly from animal research.
• Tier D, mostly preclinical. The evidence comes almost entirely from animal and laboratory studies.

A higher tier does not mean a compound is right for anyone, and a lower tier does not mean it has been shown not to work. Approval in tier S covers one specific medical use, under a prescriber's care.

Tier S: FDA-approved

Approved by the FDA for at least one specific indication.

Tier A: Strong human trials

Randomized human trials published in major journals, or a former FDA approval, but not currently approved.

Tier B: Some human evidence

Human studies or approvals outside the US exist, but the evidence is smaller, older, regional or mixed.

Tier C: Early human data

Pharmacokinetic, pilot or safety studies in people; the effects people talk about come mostly from animal research.

Tier D: Mostly preclinical

The evidence comes almost entirely from animal and laboratory studies.

What a tier does not tell you

Approval is for a product and a use. Semaglutide's approval covers Wegovy and Ozempic for their labeled indications. A compounded or research-grade vial of the same compound is a separate product that no regulator has reviewed.

Evidence is not the same as safety for you. Even tier S medicines have known side effects and reasons not to use them, which is why they are prescribed. Each compound page lists the side effects reported in research.

Research-chemical quality is unverified. Outside approved products, nobody independently checks what is in a vial or how pure it is.

Sources

The key source for each entry. Every compound page lists its full set of sources.

1. WEGOVY (semaglutide) injection, for subcutaneous use - Highlights of Prescribing Information. U.S. Food and Drug Administration, 2024. Fda label
2. ZEPBOUND (tirzepatide) injection, for subcutaneous use - Highlights of Prescribing Information. U.S. Food and Drug Administration, 2024. Fda label
3. EGRIFTA (tesamorelin for injection), for subcutaneous use - Prescribing Information. U.S. Food and Drug Administration, 2019. Fda label
4. VYLEESI (bremelanotide injection) - Highlights of Prescribing Information. U.S. Food and Drug Administration, 2019. Fda label
5. SAXENDA (liraglutide) injection, for subcutaneous use - Highlights of Prescribing Information. U.S. Food and Drug Administration, 2026. Fda label
6. FOUNDAYO (orforglipron) tablets, for oral use - Highlights of Prescribing Information. U.S. Food and Drug Administration, 2026. Fda label
7. GENOTROPIN (somatropin) for injection, for subcutaneous use - Prescribing Information. U.S. Food and Drug Administration, 2025. Fda label
8. ELMIRON (pentosan polysulfate sodium) capsules - Prescribing Information. U.S. Food and Drug Administration, 2021. Fda label
9. GATTEX (teduglutide) for injection, for subcutaneous use - Prescribing Information. U.S. Food and Drug Administration, 2025. Fda label
10. PITOCIN- oxytocin injection (prescribing information). U.S. Food and Drug Administration (via DailyMed), 2026. Fda label
11. FORZINITY (elamipretide) for injection, for subcutaneous use - Prescribing Information. U.S. Food and Drug Administration, 2025. Fda label
12. SCENESSE (afamelanotide) implant, for subcutaneous use: prescribing information. U.S. Food and Drug Administration, 2019. Fda label
13. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. Jastreboff AM et al. N Engl J Med, 2023. Human trial
14. Once-weekly cagrilintide for weight management in people with overweight and obesity: a multicentre, randomised, double-blind, placebo-controlled and active-controlled, phase 2 trial. Lau DCW et al. The Lancet, 2021. Human trial
15. Determination That GEREF (Sermorelin Acetate) Injection ... Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness. Federal Register / U.S. Food and Drug Administration, 2013. Regulatory document
16. Glucagon and GLP-1 receptor dual agonist survodutide for obesity: a randomised, double-blind, placebo-controlled, dose-finding phase 2 trial.. le Roux CW et al. Lancet Diabetes Endocrinol, 2024. Human trial
17. Petrelintide, a human amylin analogue for the treatment of obesity (ZUPREME 1): a randomised, double-blind, placebo-controlled, phase 2 trial.. Garvey WT et al. Lancet Diabetes Endocrinol, 2026. Human trial
18. The Pulsatile Gonadorelin Pump Induces Earlier Spermatogenesis Than Cyclical Gonadotropin Therapy in Congenital Hypogonadotropic Hypogonadism Men. Zhang L et al. Am J Mens Health, 2019. Human trial
19. Combination therapy with thymosin alpha1 and interferon for the treatment of chronic hepatitis C infection: a randomized, placebo-controlled double-blind trial. Sherman KE et al. Hepatology, 1998. Human trial
20. Effectiveness of semax in acute period of hemispheric ischemic stroke: a clinical and electrophysiological study. Gusev EI et al. Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova, 1997. Human trial
21. Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia. Zozulia AA et al. Zhurnal Nevrologii i Psikhiatrii Imeni S.S. Korsakova, 2008. Human trial
22. Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. Pickart L et al. International Journal of Molecular Sciences, 2018. Review
23. Once-Weekly Mazdutide in Chinese Adults with Obesity or Overweight.. Ji L et al. N Engl J Med, 2025. Human trial
24. Efficacy and safety of a biased GLP-1 receptor agonist ecnoglutide in adults with overweight or obesity: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial.. Ji L et al. Lancet Diabetes Endocrinol, 2025. Human trial
25. Effect of tesofensine on bodyweight loss, body composition, and quality of life in obese patients: a randomised, double-blind, placebo-controlled trial.. Astrup A et al. Lancet, 2008. Human trial
26. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. Nass R et al. Ann Intern Med, 2008. Human trial
27. Cerebrolysin after moderate to severe traumatic brain injury: prospective meta-analysis of the CAPTAIN trial series.. Vester JC et al. Neurological Sciences, 2021. Human trial
28. [Noopept in the treatment of mild cognitive impairment in patients with stroke].. Amelin AV et al. Zhurnal Nevrologii i Psikhiatrii imeni S.S. Korsakova, 2011. Human trial
29. Intravenous aviptadil and remdesivir for treatment of COVID-19-associated hypoxaemic respiratory failure in the USA (TESICO): a randomised, placebo-controlled trial.. Brown SM et al. The Lancet Respiratory Medicine, 2023. Human trial
30. Peptides of pineal gland and thymus prolong human life.. Khavinson VKh et al. Neuroendocrinology Letters, 2003. Human trial
31. Treatment with LL-37 is safe and effective in enhancing healing of hard-to-heal venous leg ulcers: a randomized, placebo-controlled clinical trial.. Grönberg A et al. Wound Repair and Regeneration, 2014. Human trial
32. [Application thymogen for preoperative preparation of elderly patients with tumor processes in abdominal cavity].. Smirnov VS et al. Advances in Gerontology, 2011. Human trial
33. Topical palmitoyl pentapeptide provides improvement in photoaged human facial skin. Robinson LR et al. Int J Cosmet Sci, 2005. Human trial
34. The anti-wrinkle efficacy of argireline, a synthetic hexapeptide, in Chinese subjects: a randomized, placebo-controlled study. Wang Y et al. Am J Clin Dermatol, 2013. Human trial
35. Larazotide acetate for persistent symptoms of celiac disease despite a gluten-free diet: a randomized controlled trial. Leffler DA et al. Gastroenterology, 2015. Human trial
36. Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Yoshino M et al. Science, 2021. Human trial
37. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Gobburu JV et al. Pharmaceutical Research, 1999. Human trial
38. Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. Bowers CY et al. Journal of Clinical Endocrinology & Metabolism, 1990. Human trial
39. Safety and Tolerability of the Hexadecapeptide AOD9604 in Humans. Stier et al. Journal of Endocrinology and Metabolism, 2013. Human trial
40. A Pilot Study Investigating Changes in the Human Plasma and Urine NAD+ Metabolome During a 6 Hour Intravenous Infusion of NAD+. Grant R et al. Frontiers in Aging Neuroscience, 2019. Human trial
41. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Reynolds JC et al. Nature Communications, 2021. Human trial
42. Growth hormone status during long-term hexarelin therapy. Rahim A et al. J Clin Endocrinol Metab, 1998. Human trial
43. Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. Laferrère B et al. J Clin Endocrinol Metab, 2005. Human trial
44. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. Teichman SL et al. J Clin Endocrinol Metab, 2006. Human trial
45. Kisspeptin-10 is a potent stimulator of LH and increases pulse frequency in men. George JT et al. J Clin Endocrinol Metab, 2011. Human trial
46. Effects of delta sleep-inducing peptide on sleep of chronic insomniac patients. A double-blind study.. Bes F et al. Neuropsychobiology, 1992. Human trial
47. Safety and efficacy of ARA 290 in sarcoidosis patients with symptoms of small fiber neuropathy: a randomized, double-blind pilot study.. Heij L et al. Molecular Medicine, 2012. Human trial
48. Clinical Safety and Efficacy Evaluation of a Dissolving Microneedle Patch Having Dual Anti-Wrinkle Effects With Safe and Long-Term Activities. Shin JY et al. Ann Dermatol, 2024. Human trial
49. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Dorr RT et al. Life Sci, 1996. Human trial
50. Glutathione for skin lightening: a regnant myth or evidence-based verity?. Sonthalia S et al. Dermatol Pract Concept, 2018. Review
51. The Prohibited List. World Anti-Doping Agency, 2026. Regulatory document
52. The effect of thymosin treatment of venous ulcers. Guarnera G et al. Annals of the New York Academy of Sciences, 2010. Human trial
53. Melanocortin-derived tripeptide KPV has anti-inflammatory potential in murine models of inflammatory bowel disease. Kannengiesser K et al. Inflammatory Bowel Diseases, 2008. Preclinical
54. Effect of Epitalon on biomarkers of aging, life span and spontaneous tumor incidence in female Swiss-derived SHR mice. Anisimov VN et al. Biogerontology, 2003. Preclinical
55. Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice.. Neelakantan H et al. Biochemical Pharmacology, 2018. Preclinical
56. Insulin-like growth factor-I (IGF-I) and especially IGF-I variants are anabolic in dexamethasone-treated rats. Tomas FM et al. Biochemical Journal, 1992. Preclinical
57. Des(1-3)IGF-I: a truncated form of insulin-like growth factor-I. Ballard FJ et al. International Journal of Biochemistry & Cell Biology, 1996. Review
58. Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage. Hill M et al. The Journal of Physiology, 2003. Preclinical
59. A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. Mendell JR et al. Molecular Therapy, 2015. Human trial
60. The effects of human GH and its lipolytic fragment (AOD9604) on lipid metabolism following chronic treatment in obese mice and beta(3)-AR knock-out mice. Heffernan M et al. Endocrinology, 2001. Preclinical
61. Reversal of obesity by targeted ablation of adipose tissue. Kolonin MG et al. Nature Medicine, 2004. Preclinical
62. Evaluation of metabolically stabilized angiotensin IV analogs as procognitive/antidementia agents.. McCoy AT et al. Journal of Pharmacology and Experimental Therapeutics, 2013. Preclinical
63. Disease modifying effect of chronic oral treatment with a neurotrophic peptidergic compound in a triple transgenic mouse model of Alzheimer's disease.. Kazim SF et al. Neurobiology of Disease, 2014. Preclinical
64. EDR Peptide: Possible Mechanism of Gene Expression and Protein Synthesis Regulation Involved in the Pathogenesis of Alzheimer's Disease.. Khavinson V et al. Molecules, 2020. Review
65. Targeted Apoptosis of Senescent Cells Restores Tissue Homeostasis in Response to Chemotoxicity and Aging.. Baar MP et al. Cell, 2017. Preclinical
66. A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Abeta.. Hashimoto Y et al. Proceedings of the National Academy of Sciences, 2001. Preclinical
67. Activation of pericentromeric and telomeric heterochromatin in cultured lymphocytes from old individuals.. Lezhava T et al. Annals of the New York Academy of Sciences, 2007. Preclinical

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