Melanotan IICosmetic / Skin
Melanocortin peptide studied for tanning and libido.
- Status
- Research / not approved
- Developer
- University of Arizona (Hruby et al.); investigational only
- Receptors / target
- Non-selective melanocortin receptor agonist (MC1R-MC5R); a synthetic cyclic analog of alpha-MSH
- FDA-approved?
- NO
- Prescription available?
- NO
- Studied for
- skin pigmentation / tanningmelanogenesissexual arousal (MC4R)appetite / energy balance
Overview
Melanotan II is a synthetic cyclic analog of alpha-melanocyte-stimulating hormone (alpha-MSH) used illicitly to darken the skin ("tanning injections") and, secondarily, for erectile/libido effects. It is an unlicensed product not approved for any use by any regulator; the US FDA, UK MHRA and Australian TGA have all issued warnings against unlicensed melanotan, and it is typically sold online as a "research chemical" not intended for human use. The related approved drug bremelanotide (PT-141) is a distinct compound and should not be conflated with melanotan II.
Mechanism
Melanotan II is a non-selective melanocortin receptor agonist, activating MC1R through MC5R. Agonism at MC1R on melanocytes stimulates eumelanin synthesis (skin darkening), while activity at central melanocortin receptors (MC3R/MC4R) is thought to underlie its appetite-suppressing and erectogenic effects. Its broad, non-selective activity — combined with sympathomimetic-type effects reported clinically — likely contributes to its varied adverse-effect profile.
Clinical evidence
There are no large controlled human trials supporting melanotan II for any indication, and it has no approved use anywhere; the human literature consists largely of small studies and adverse-event case reports. Documented dermatologic effects include darkening and proliferation of melanocytic moles, with published case reports of melanoma and melanoma in situ in melanotan users (often confounded by concurrent UV/sunbed exposure). The safety signals here come from human case reports; preclinical melanocortin pharmacology only informs the mechanism.
Safety profile
Melanotan II carries real, well-documented safety concerns and should be treated as high-risk. Common short-term effects include nausea/vomiting, facial flushing, reduced appetite and spontaneous erections. Serious harms in published human case reports include systemic toxicity with rhabdomyolysis and renal dysfunction, acute ischemic priapism requiring surgical intervention, posterior reversible encephalopathy syndrome, and darkening/changing moles with associated melanoma concern. Risks are compounded by product impurity, incorrect self-dosing and non-sterile injection. Because it is unlicensed and unmonitored, the true incidence of these events is unknown, and multiple national regulators explicitly warn against its use. Research use only; nothing here is medical advice.
- Days to weeks
Skin darkening develops over days to weeks of dosing; libido/erectile effects can occur acutely after a dose.
- Safety note
It is unlicensed with documented harms (nausea, darkening/changing moles and melanoma reports, priapism, rhabdomyolysis); multiple regulators warn against use.
What people describe in forums, blogs and uncontrolled clinic write-ups — experiential and unverified, not clinical evidence and not medical advice.
- Deep tan that holds with little sunthe main reason people use it
The core draw is getting and keeping a tan with minimal UV. In an r/Melanotan2 thread from someone in a near-sunless winter climate, a commenter with Scandinavian genetics says they 'do GREAT' on MT-II and maintain their color through winter on only a few minutes of UV. Self-reported and unverified.
Reddit — r/Melanotan2 - Tans fair / hard-to-tan skina very common motivation
A recurring reason people try MT-II is skin that 'never tans' — burning instead of browning, or lots of freckles. Users with very fair skin report finally developing color, but the same threads stress you still need some UV or the result looks washed-out and greyish rather than a true tan. Anecdotal.
Reddit — r/Melanotan2 - Increased libido and spontaneous erectionsfrequently mentioned
MT-II is the parent of the libido drug PT-141, and users commonly note a rise in sex drive — sometimes spontaneous erections after a dose. Some welcome it, others find it an unwanted side effect. Reported as a real and often strong effect, but individual. Unverified.
Reddit — r/Melanotan2 - New moles and darkening freckles/molesone of the most reported concerns
A very common and safety-relevant report is that existing moles and freckles darken and new spots can appear during use — some users also mention melasma-type facial pigmentation. The community treats this as a real reason to have moles watched by a dermatologist, not a cosmetic footnote. Anecdotal but frequently repeated.
Reddit — r/Melanotan2 - Nausea, flushing and dose sensitivitycommonly reported early on
Early doses commonly bring nausea, facial flushing and a general 'off' feeling, and users repeatedly report that side effects get much worse if they push the dose — several describe backing off after bad reactions at higher amounts and starting very low instead. A tolerability, not a benefit, theme.
Reddit — r/Melanotan2
Reported in published literature and user reports. Not a complete list, and not medical advice.
- Nausea / vomiting
- Facial flushing
- Spontaneous erections
- Darkening of moles / new nevi
- Appetite suppression
If severe or unexpected symptoms occur, contact a qualified medical professional. PEPTIDES·INDEX does not provide medical advice.
- History of melanoma or atypical/changing moles — case reports link melanotan II to mole changes and melanoma
- Cardiovascular disease or risk — caution given reported sympathomimetic-type effects (blood-pressure and heart-rate changes)
- No documented human drug interactionsInteraction profile uncharacterized in humans (unlicensed research chemical; only limited case-report data exist)
Compare
- vs Melanotan I
The MC1R-selective analog (afamelanotide) that is FDA-approved as Scenesse for EPP — a far better-characterized, regulated alternative
- vs PT-141
A related cyclic melanocortin agonist (bremelanotide) that is FDA-approved as Vyleesi; distinct compound and should not be conflated with melanotan II
FAQ
Is Melanotan II legal or approved?
No. Melanotan II is an unlicensed product not approved for any use by any regulator. The US FDA, UK MHRA and Australian TGA have all warned against unlicensed melanotan; it is typically sold online as a research chemical not intended for human use.
What are the documented dangers of Melanotan II?
Published human case reports include systemic toxicity with rhabdomyolysis and renal dysfunction, acute ischemic priapism requiring surgical intervention, posterior reversible encephalopathy syndrome, and darkening/changing moles with associated melanoma reports. Common short-term effects are nausea, vomiting, flushing and spontaneous erections.
Does Melanotan II cause melanoma?
It cannot be stated as proven cause and effect, but multiple case reports describe melanoma and melanoma in situ in melanotan II users (often with concurrent UV/sunbed exposure), alongside darkening and proliferation of moles. Anyone with a melanoma or atypical-mole history should avoid it.
Why does Melanotan II cause erections and reduced appetite?
It is a non-selective melanocortin agonist that activates central MC3R and MC4R in addition to MC1R in skin. MC4R activity drives the erectogenic effect (sometimes to the point of painful, prolonged priapism reported in case reports) and contributes to appetite suppression, while MC1R activity produces the skin darkening.
How does Melanotan II differ from approved bremelanotide (PT-141)?
Bremelanotide (Vyleesi) is an FDA-approved cyclic melanocortin agonist with defined dosing, monitoring and pharmaceutical-grade manufacturing. Melanotan II is a structurally related but unlicensed research chemical with no quality control, no approved dose and documented serious harms. A regulated approval does not transfer from one to the other.
Why do regulators warn against Melanotan II?
Because it is sold without any marketing authorization, often as unverified-purity powder for self-injection, and is linked to serious adverse events. The US FDA, UK MHRA and Australian TGA have all issued public warnings against unlicensed melanotan tanning products.
Similar compounds
Starting references for the library summary. These are not dosing instructions or medical advice.
For research-use educational context only. Not medical advice and not a recommendation to use any compound. Consult a qualified healthcare professional before any health decision.