What Melanotan II is. And where it comes from
Melanotan II (MT-II) is a synthetic cyclic 7-amino-acid analogue of alpha-melanocyte-stimulating hormone (alpha-MSH). It was developed at the University of Arizona in the 1980s-90s as part of a program to create a "tanning pill" that would reduce UV exposure. Early human trials confirmed pigmentation effects but also revealed significant sexual arousal as a side effect. PT-141 (bremelanotide, later approved as Vyleesi) was derived from MT-II by removing the MC1R tanning activity.
Melanotan II is not FDA-approved. Afamelanotide (Melanotan I / Scenesse) is a different compound from the same research program that is FDA-approved, for a rare skin condition called erythropoietic protoporphyria, not for tanning.
Mechanism, in plain English
MT-II is a non-selective melanocortin receptor agonist. It activates four of the five melanocortin receptors:
- MC1R. Expressed on melanocytes in the skin. Activation stimulates eumelanin (brown/black pigment) production, producing UV-independent tanning.
- MC3R/MC4R. Expressed in the hypothalamus and other CNS regions. Responsible for appetite suppression, sexual arousal effects, and some cardiovascular effects.
- MC5R. Expressed in exocrine glands; less well-characterized in humans.
What the evidence shows
Pigmentation. Dorr et al. 1996 demonstrated UV-independent skin darkening in a small placebo-controlled trial. Effects were real but accompanied by significant nausea and spontaneous erections.
Sexual function. Wessells et al. 1998 (J Urology) showed that MT-II produced erectile responses in men with psychogenic erectile dysfunction in a small double-blind crossover study.
There are no large phase 3 RCTs for MT-II for any indication. Its non-selective receptor profile and adverse event burden led researchers to pivot to the more selective PT-141 (bremelanotide), which achieved FDA approval.
FDA status (this month)
Melanotan II is NOT FDA-approved for any indication. It is not legally sold as a drug or supplement in the US. Last reviewed 2026-08-09.
Common synonyms researchers use
Melanotan II · MT-II · MT-2 · cyclo[Nle4,D-Phe7]-alpha-MSH (chemical description)
Safety & adverse-event landscape
MT-II has a significant adverse event burden in human studies: nausea, vomiting, spontaneous erections (in men), facial flushing, fatigue, and transient increases in blood pressure. There are also reports of nevus (mole) darkening and new mole appearance. The non-selective receptor profile contributes to the breadth of side effects. MT-II is not approved and its long-term safety profile is not established. Always consult a qualified healthcare provider.
Frequently asked questions
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What the preclinical evidence shows
The bulk of the published evidence comes from rodent models, tendon transection and Achilles repair, vascular ligation, NSAID-induced gut damage, and fistulizing colitis models. Effects have been reported as positive in tendocyte outgrowth assays, in vascular angiogenesis assays, and in rat colitis models. The most-cited review is Sikiric (2018) in Current Pharmaceutical Design.
Human published data is limited to small case-series reports and registry submissions. There are no large randomized controlled trials to date. The bulk of the discussion in online health communities reflects animal extrapolation, not human-trial data.
Strong preclinical animal research supports investigation into tendon, ligament, and gastrointestinal healing. Human clinical evidence remains limited despite extensive anecdotal use.
FDA status (this month)
BPC-157 is not FDA-approved for any human indication. On July 23-24, 2026, an FDA Pharmacy Compounding Advisory Committee reviewed several peptides including BPC-157 and voted to recommend reviewing whether compounding pharmacies may be allowed to produce them. A rule-making step would be required before any compounding access is granted. And that step is not FDA approval. Coverage: NYT briefing. Last reviewed 2026-08-09.
Common synonyms researchers use
BPC 157 · BPC-157 · Body Protection Compound 157 · PL-14736 (early proprietary designation in the Sikiric et al. literature).
Safety & adverse-event landscape
In the published preclinical literature, BPC-157 has been administered to rodents over short and medium-term protocols without reported mortality. Adverse-event data in humans is limited. The compound's interaction with nitric oxide pharmacology suggests theoretical considerations with vasodilator and cardiovascular medications, consult your provider if you take any.
Peptexa is an educational resource. We do not provide dosing guidance, sourcing recommendations, or protocol advice. Always consult a qualified healthcare provider before any decision that involves a peptide, supplement, or therapeutic compound.
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