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D2C Peptides

Research goal

Peptides and tanning

The tanning peptides are lab-made versions of alpha-MSH, the hormone that darkens skin.22434 Melanotan 2 is not FDA approved, and its only tanning data come from a 1996 pilot study in which 2 of 3 men darkened.21 Melanotan 1 (afamelanotide) is approved only as Scenesse, an implant for adults with phototoxic reactions from erythropoietic protoporphyria.3 This page maps what published sources report on each and makes no promise.

This page summarizes published sources for information only. It is not medical advice and does not tell anyone to use a product. Questions about your own health belong with a licensed clinician. For questions about an order or a product, contact us.

How tanning peptides work

Melanotan 2 darkens skin mainly by switching on melanocortin 1 receptors (MC1R) on pigment cells.21 That raises production of eumelanin, the brown-black pigment, even without sun exposure.21 Melanotan 2 is a lab-made, ring-shaped peptide of 7 amino acids modeled on the body's alpha-melanocyte-stimulating hormone (alpha-MSH).22 Because it is non-selective, it also acts on other melanocortin receptors, and it was later studied for erectile dysfunction.6 It came from a University of Arizona family of long-acting melanocortin analogs that also includes Melanotan 1.234

Compounds studied for tanning

Melanotan 2

In a 1996 pilot study, 2 of 3 healthy men had measurably darker skin on the face, upper body and buttock one week after dosing ended.1 No larger tanning trial of Melanotan 2 was found.1 The men reported mild nausea, sleepiness and fatigue at the highest dose, and a stretching and yawning complex tied to spontaneous erections.2425 That study measured pigment, not sunburn, so whether a Melanotan 2 tan protects the skin is unknown.1 In 2007, FDA warned a seller over marketing Melanotan II as a tanning agent and skin cancer preventive.2 Read What is Melanotan 2?, or see Melanotan 2 for sale.

Melanotan 1 (afamelanotide)

Melanotan 1 is a different, linear peptide that binds mainly MC1R.45 As afamelanotide, FDA approved it in 2019 as Scenesse, an implant to increase pain-free light exposure in adults with erythropoietic protoporphyria (EPP).263 Its label still tells patients to keep up sun and light protection, and recommends a full body skin exam twice a year because it can darken moles.2728 In a 2004 study, 3 of 4 volunteers given Melanotan 1 before UV-B exposure tanned and had 47% fewer sunburn cells.2930 The Melanotan 2 profile compares the two in more detail.

PT-141 (bremelanotide)

PT-141 was developed as an analog of Melanotan 2.31 As bremelanotide, it is the active ingredient of Vyleesi, approved for a sexual desire disorder in premenopausal women and not for tanning.15 Of the melanocortin receptors, it activates MC1R, the pigment receptor, most strongly.32 Its label warns of patchy darkening of the skin that was not confirmed to clear in every patient after stopping.1716 Read What is PT-141?, or see PT-141 for sale.

KPV

KPV is not a tanning compound.33 It is the last three amino acids of alpha-MSH, and reviews report that it lacks the pigment-making activity of the full hormone.3433 In lab tests, it did not bind MC1 receptors.35 FDA's 2026 review identified no human data on KPV at all.36 Read What is KPV?, or see KPV for sale.

Safety signals reported with melanotan

  • Moles. New and darker moles have appeared within 24 hours of a single Melanotan 2 injection.10 In a review of 179 published patients with sudden-onset moles, immunosuppressive drugs, chemotherapy or melanotan were the suspected cause in 41%, and the data could not show cancer risk.3738
  • Melanoma reports. A 2017 review counted four case reports of melanoma arising from existing moles during or shortly after melanotan use, and said conclusive evidence of a link is lacking.39
  • Serious events. FDA lists published case reports of melanoma, posterior reversible encephalopathy syndrome (a brain condition), sympathomimetic toxicity and priapism with Melanotan II.40 A 2026 review of tanning products adds muscle breakdown and kidney infarction to the harms of unregulated melanotan use.41
  • Immune reactions. FDA says compounded Melanotan II may provoke immune reactions because of possible aggregation or peptide-related impurities.42

How to read this research

Size up the evidence first. Melanotan 2's tanning data come from 3 men in one pilot study, and Melanotan 1's from 4 treated volunteers; most of the rest are case reports and animal work.129 Case reports show what can happen, not how often, which is why the melanoma reports remain unproven as a cause.39 A darker tan is not the same as protection, and even the approved Melanotan 1 implant keeps sun protection on its label.27 Product identity matters too: vials of Melanotan 2 sold online as 10 mg held 4.32 to 8.84 mg, and some had unknown impurities.4344 See the lab results page for what this store publishes about testing. Pigment changes to moles, nails and gums are also covered on the skin and hair page, and the safety basics guide explains how to weigh compounds that are not approved.

Other research goals

Frequently asked questions

What is better, melanotan 1 or 2?

Neither is approved for cosmetic tanning, and they differ in structure, receptors and status.32 Melanotan 1 (afamelanotide) is a linear peptide that binds mainly MC1R, the pigment receptor.45 It is FDA approved as Scenesse, an implant for adults with phototoxic reactions from erythropoietic protoporphyria (EPP).3 Melanotan 2 is a shorter, ring-shaped peptide that switches on several melanocortin receptors, and its human studies reported nausea and erections.64 It is not FDA approved.2

Does melanotan 2 affect the heart?

Animal studies and case reports suggest it can. In conscious mice, Melanotan 2 raised blood pressure and heart rate in a dose-dependent way.7 In rats, a 10-day infusion into the brain raised heart rate by about 27 beats per minute.8 A man who injected Melanotan 2 bought online to darken his skin had a heart rate of up to 146 beats per minute, followed by muscle breakdown and kidney problems.9

Can Melanotan 2 make your eyes lighter?

No published study or case report found for this page shows Melanotan 2 changing eye color. Its documented pigment effects are darker skin, moles, nails and gums.1101112 In 2024 FDA quoted an eye-drop seller's claim that melanotan raises melanin in the eyes, and found that seller's eye-lightening drops to be unapproved new drugs.1314

Does PT-141 make you tan?

PT-141 is not approved as a tanning product.15 As bremelanotide, it is the active ingredient of Vyleesi, approved for hypoactive sexual desire disorder in premenopausal women.15 Patchy darkening of the face, gums or breasts is a labeled side effect.16 It affected 1% of patients with up to 8 doses a month and 38% after 8 days of daily dosing.1716 People with dark skin were more likely to get it, and it did not clear in every patient after stopping.1716 The prescriber sets the dose.

Does melanotan 2 increase oxytocin?

In animals, it acts on oxytocin cells. In prairie voles, Melanotan 2 activated oxytocin neurons in the hypothalamus and increased oxytocin release in the brain.18 In rats, an intravenous dose made oxytocin neurons fire faster without triggering local oxytocin release, and a nasal dose did not activate those neurons.1920 Both findings come from animal studies.

Written by D2C Peptides Editorial Team.

Pending qualified review.

Updated .

Sources

  1. Evaluation of melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study (Dorr et al., PMID 8637402), pigmentation excerpt. Life Sciences, 1996.
  2. FDA Fast Facts: FDA Warns Melanotan II Maker (US Pharm. 2007;32(10):72), warning letter excerpt. U.S. Pharmacist, 2007.
  3. SCENESSE (afamelanotide) implant, prescribing information, revised 08/2024: indication. U.S. Food and Drug Administration (Drugs@FDA label, NDA 210797), 2024.
  4. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization (Hadley and Dorr, PMID 16412534), MT1 vs MT2 excerpt. Peptides, 2006.
  5. Same source as 3: mechanism of action.
  6. Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II (Wessells et al., PMID 11035391), design excerpt. International Journal of Impotence Research, 2000.
  7. Hemodynamic actions and mechanisms of systemically administered alpha-MSH analogs in mice (Rinne et al., PMID 22982611). Peptides, 2012.
  8. Systemic but not central nervous system nitric oxide synthase inhibition exacerbates the hypertensive effects of chronic melanocortin-3/4 receptor activation (do Carmo et al., PMID 21263126), results excerpt. Hypertension, 2011.
  9. Melanotan II injection resulting in systemic toxicity and rhabdomyolysis (Nelson et al., PMID 23121206), case excerpt. Clinical Toxicology, 2012.
  10. Eruptive naevi and darkening of pre-existing naevi 24 h after a single mono-dose injection of melanotan II (Schulze et al., PMID 24334249; letter, no abstract). European Journal of Dermatology, 2014.
  11. Melanotan-associated transverse melanonychia (Paurobally et al., PMID 22182016; letter, no abstract). Journal of the European Academy of Dermatology and Venereology, 2013.
  12. Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report (Bonchev, PMID 41752902), follow-up excerpt. Life (Basel), 2026.
  13. Warning Letter: LightEyez Limited, MARCS-CMS 665450, February 15, 2024, quoted website claim. U.S. Food and Drug Administration, 2024.
  14. Same source as 13: FDA finding.
  15. VYLEESI (bremelanotide injection) prescribing information: Indications and Usage. DailyMed, U.S. National Library of Medicine (label by Cosette Pharmaceuticals, revised 3/2024), 2024.
  16. Same source as 15: VYLEESI prescribing information: focal hyperpigmentation (resolution and body sites).
  17. Same source as 15: VYLEESI prescribing information: Warning 5.2, focal hyperpigmentation (incidence).
  18. Melanocortin Receptor Agonists Facilitate Oxytocin-Dependent Partner Preference Formation in the Prairie Vole (Modi et al., PMID 25652247), oxytocin excerpt. Neuropsychopharmacology, 2015.
  19. Effect of Melanotan-II on Brain Fos Immunoreactivity and Oxytocin Neuronal Activity and Secretion in Rats (Paiva et al., PMID 28009464), electrophysiology excerpt. Journal of Neuroendocrinology, 2017.
  20. Same source as 19: route excerpt.
  21. Same source as 12: mechanism excerpt.
  22. Same source as 1.
  23. Same source as 4: design excerpt.
  24. Same source as 1: side effects excerpt.
  25. Same source as 1: dose escalation excerpt.
  26. Drugs@FDA: NDA 210797, SCENESSE (afamelanotide) implant, approval history. U.S. Food and Drug Administration, 2026.
  27. Same source as 3: sun protection.
  28. Same source as 3: skin monitoring warning.
  29. Effects of a superpotent melanotropic peptide in combination with solar UV radiation on tanning of the skin in human volunteers (Dorr et al., PMID 15262693), design excerpt. Archives of Dermatology, 2004.
  30. Same source as 29: results excerpt.
  31. Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization (Hadley ME, Dorr RT), PMID 16412534. Peptides (abstract via Europe PMC), 2006.
  32. Same source as 15: VYLEESI prescribing information: Mechanism of Action (12.1) and Pharmacodynamics (12.2).
  33. Are melanocortin peptides future therapeutics for cutaneous wound healing? (Böhm M, Luger T) [PMID 30661264]. Experimental Dermatology (abstract via NLM PubMed E-utilities), 2019.
  34. Alpha-melanocyte-stimulating hormone and related tripeptides: biochemistry, antiinflammatory and protective effects in vitro and in vivo, and future perspectives for the treatment of immune-mediated inflammatory diseases (Brzoska T et al.) [PMID 18612139]. Endocrine Reviews (abstract via NLM PubMed E-utilities), 2008.
  35. Effects of melanocortin peptides on lipopolysaccharide/interferon-gamma-induced NF-kappaB DNA binding and nitric oxide production in macrophage-like RAW 264.7 cells: evidence for dual mechanisms of action (Mandrika I et al.) [PMID 11239505]. Biochemical Pharmacology (abstract via NLM PubMed E-utilities), 2001.
  36. FDA Evaluation of KPV-Related Bulk Drug Substances (KPV (Free Base) and KPV acetate) for Inclusion on the 503A Bulk Drug Substances List, FDA briefing document for the July 23-24, 2026 PCAC meeting (memo dated 5/12/2026). U.S. Food and Drug Administration, 2026.
  37. Eruptive Melanocytic Nevi: A Review (Burian and Jemec, PMID 31119650), causes excerpt. American Journal of Clinical Dermatology, 2019.
  38. Same source as 37: limitation excerpt.
  39. Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues: a review (Habbema et al., PMID 28266027), melanoma excerpt. International Journal of Dermatology, 2017.
  40. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 04/22/2026), Melanotan II case reports entry. U.S. Food and Drug Administration, 2026.
  41. Insights into Tanning Biology and Tanning Products (Resnick et al., PMID 41890775), melanotan excerpt. Journal of Clinical and Aesthetic Dermatology, 2026.
  42. Same source as 40: Melanotan II immunogenicity entry.
  43. Identification and characterization by LC-UV-MS/MS of melanotan II skin-tanning products sold illegally on the Internet (Breindahl et al., PMID 24771717), content excerpt. Drug Testing and Analysis, 2015.
  44. Same source as 43: impurities excerpt.