Compound record · Sexual health
Melanotan II
Also MT-II · MT2 · Melanotan 2 · Melanotan-II · Barbie peptide · Tanning injection · Nasal tanning spray
Non-selective melanocortin receptor agonist (α-MSH analogue)
Unlicensed tanning and libido peptide that regulators have publicly warned against
Record reviewed 1 September 2026 · 6 references
- Class
- Non-selective melanocortin agonist (α-MSH analogue)
- Human trials
- 3-man phase 1 (1996) and two 10-man erectile-dysfunction pilots; development abandoned
- Regulatory status
- Never approved anywhere; MHRA, TGA and FDA warnings
- Anti-doping
- Not named on the WADA list, but non-approved substances are prohibited under S0
- Typical sale form
- Illegal injectable vials and nasal tanning sprays
01 Overview
What Melanotan II is
Summary
Melanotan II is a synthetic cyclic analogue of the pigment hormone α-MSH developed in the 1990s as a sunless-tanning drug. Development was abandoned after early trials, but it is now sold illegally online as injections and nasal sprays for tanning and sexual effects. The MHRA, the TGA and the FDA have all warned against its use because of reports of new or changing moles, melanoma, kidney damage, rhabdomyolysis, encephalopathy and prolonged erections, and because the products' contents are unknown. It has never been approved anywhere.
Mechanism
Activates all melanocortin receptors without selectivity: MC1 on skin pigment cells (tanning and darkening of moles), MC4 in the brain (sexual arousal, appetite suppression, blood-pressure and heart-rate changes) and MC3/MC5 (less well understood). Its deamidated metabolite is bremelanotide (PT-141), which was developed separately as a more selective MC4 agonist.
02 Evidence by goal
What has been shown, for which goal
Grades follow one scale across the site. Preliminary overall means: early-phase human data or case series; findings need replication.
Skin & cosmetic
PreliminaryTanning was documented in a 1996 phase 1 study of three men given subcutaneous injections on alternate days for two weeks; two of the three darkened. No larger controlled study of Melanotan II for tanning was ever published — the tanning programme moved to the related compound Melanotan I (afamelanotide), which became a licensed medicine for a rare light-sensitivity disorder, not for cosmetic tanning.
Sexual health
PreliminaryTwo double-blind crossover pilots (10 men each) in the late 1990s found 0.025 mg/kg subcutaneously produced erections without sexual stimulation in most men with psychogenic or organic erectile dysfunction, with nausea and yawning as the main side effects. Development stopped; the effect was pursued instead through bremelanotide. No data in women.
Fat loss / body composition
InsufficientAppetite suppression is a consistent side effect through MC4 receptor activation, and some users take it for that reason, but no study has ever measured weight or body composition.
03 Regulatory status
Where it is authorised, and for what
Status is recorded per jurisdiction from regulator sources and reviewed by hand. It is never inferred from another region's decision.
United Kingdom
Not authorisedNever licensed; MHRA has repeatedly removed products and advises users to stop.
Injectable Melanotan II is classed as an unlicensed medicine and cannot legally be sold, supplied or advertised. The MHRA has taken enforcement action for over a decade and states its advice to anyone who has used Melanotan II injections or nasal sprays is to stop immediately and report side effects via the Yellow Card scheme. Nasal sprays sold without medicinal claims currently fall outside medicines law, which is a regulatory gap rather than a sign of safety.
04 Dosing research
What the evidence says about exposure
Published human studies and the doses, routes and durations they used — reported as research information, not a recommendation.
Research information — not a recommendation. These are the exposures used in published human studies, reported so you can see what has been tested. They are not dosing instructions and do not apply to any individual.
Study 01
Pilot phase 1 study of Melanotan II in healthy men (tanning)
Dorr RT et al., Life Sci 1996;58:1777–1784 · Source
- Design
- Single-blind, placebo-controlled, alternating-day saline or Melanotan II, dose escalation
- Population
- Healthy adult men
- Participants
- n = 3
- Duration
- Two weeks (five active doses)
- Route
- Subcutaneous injection
- Doses studied
- Subcutaneous Melanotan II starting at 0.01 mg/kg, escalated in 0.005 mg/kg steps to 0.025–0.03 mg/kg, on alternating days with saline
- Outcome at this exposure
- Two of three men developed measurable darkening of the face, upper body and buttocks one week after dosing ended. The authors recommended 0.025 mg/kg as the maximum dose for further study.
- Adverse events observed
- Mild nausea at most dose levels; stretching and yawning followed by spontaneous penile erections lasting intermittently for 1–5 hours in all three men at 0.025 mg/kg; grade 2 somnolence and fatigue at 0.03 mg/kg.
Study 02
Melanotan II in men with psychogenic erectile dysfunction
Wessells H et al., J Urol 1998;160:389–393 · Source
- Design
- Randomised, double-blind, placebo-controlled crossover
- Population
- Men with erectile dysfunction of no known organic cause
- Participants
- n = 10
- Duration
- Single doses with 6-hour RigiScan monitoring
- Route
- Subcutaneous injection
- Doses studied
- 0.025 mg/kg Melanotan II subcutaneously versus vehicle
- Outcome at this exposure
- Clinically apparent erections in 8 of 10 men; mean duration of tip rigidity above 80% was 38 minutes versus 3 minutes with placebo (p = 0.0045), without sexual stimulation.
- Adverse events observed
- Nausea, stretching and yawning, and decreased appetite were more frequent than with placebo; none required treatment in this study.
Study 03
Melanotan II in men with erectile dysfunction and organic risk factors
Wessells H et al., Urology 2000;56:641–646 · Source
- Design
- Randomised, double-blind, placebo-controlled crossover (two doses each of active and vehicle)
- Population
- Men with erectile dysfunction and organic risk factors (for example diabetes, vascular disease)
- Participants
- n = 10
- Duration
- Single doses with 6-hour RigiScan monitoring
- Route
- Subcutaneous injection
- Doses studied
- 0.025 mg/kg Melanotan II subcutaneously versus vehicle, each given twice
- Outcome at this exposure
- Erections after 12 of 19 active injections versus 1 of 21 placebo injections; tip rigidity above 80% lasted 45 minutes versus 2 minutes (p = 0.047); self-rated sexual desire was higher after Melanotan II.
- Adverse events observed
- Nausea and stretching/yawning were more frequent with Melanotan II; 4 of 19 active injections caused severe nausea.
These early-phase studies involved 23 men in total, given single supervised doses or a two-week course, and the compound was never taken further because of its side-effect profile. Nothing is known about the safety of the repeated 'loading and maintenance' injections or daily nasal sprays used for tanning, which typically expose users for far longer than any trial did. Illegal products are also of unknown strength, so a stated dose means little.
05 Safety
Adverse effects and contraindications
Common effects seen in trials or reports, serious effects that warrant urgent review, and conditions under which use is not appropriate or needs assessment.
Common adverse effects
- Nausea and vomiting (very common, especially with early doses)
- Facial flushing
- Loss of appetite
- Yawning and stretching followed by spontaneous erections
- Fatigue and drowsiness
- Darkening of existing moles and freckles; new moles
- Uneven or patchy pigmentation
- Injection-site reactions or nasal irritation
Serious adverse effects
- Melanoma and rapidly changing or eruptive moles (case reports; regulators' principal concern)
- Priapism (prolonged painful erection needing emergency treatment)
- Rhabdomyolysis (muscle breakdown) and acute kidney injury
- Renal infarction
- Posterior reversible encephalopathy syndrome (brain swelling with headache, seizures, visual loss)
- Sympathomimetic toxidrome: severe hypertension, rapid heart rate, agitation
- Infection or contamination reactions from illegally manufactured products
Contraindications
- Melanoma or atypical molesDo not use
Melanotan II stimulates pigment cells directly. Case reports describe new melanomas and rapidly changing or eruptive moles in users; anyone with a history of melanoma or atypical moles should not be exposed to it.
- CancerCaution
Beyond melanoma, the effect of a non-selective melanocortin agonist on other cancers is unknown; any cancer history should be disclosed.
- Cardiovascular diseaseCaution
Melanocortin agonists raise blood pressure and alter heart rate; the FDA has cited a sympathomimetic toxidrome (racing heart, hypertension, agitation) in case reports. Existing heart disease increases the risk.
- High blood pressureCaution
Expected transient blood-pressure rises after each dose (documented for the related medicine bremelanotide) are more dangerous with pre-existing hypertension, and posterior reversible encephalopathy syndrome has been reported.
- Kidney diseaseCaution
Case reports include renal infarction and rhabdomyolysis-related kidney injury after Melanotan II use; pre-existing kidney disease reduces reserve.
- Blood-clotting disorderCaution
Reported renal infarction and priapism point to vascular effects; a clotting disorder or blood-thinner use adds uncertainty.
Do not use = should not be used · Caution = needs assessment
06 Interactions
Medicine classes that need review
Grouped by how seriously the combination should be taken. Class labels match the medicines questionnaire in the assessment.
- Major
- Moderate
- Minor
Moderate
Monitoring or dose review is usually advised.
Blood pressure medicine
Ramipril, amlodipine, losartan
Melanocortin agonists transiently raise blood pressure after each dose, working against blood-pressure treatment; the combination is unstudied.
Erectile dysfunction medicine
Sildenafil, tadalafil
Melanotan II produces spontaneous erections on its own; combining it with sildenafil-type medicines risks prolonged, painful erections (priapism), which has been reported with Melanotan II alone.
Stimulant
Methylphenidate, lisdexamfetamine
The FDA has cited sympathomimetic toxidrome with Melanotan II; adding stimulant medicines could compound the cardiovascular effects.
Minor
Generally compatible; awareness is sufficient.
GLP-1 / incretin medicine
Ozempic, Wegovy, Mounjaro, Saxenda
Both suppress appetite and cause nausea; the combination is unstudied and may be poorly tolerated.
07 Pregnancy & breastfeeding
Status in pregnancy
No human or animal reproductive data exist, the related medicine bremelanotide caused fetal harm in animal studies, and regulators advise that nobody should use Melanotan II. It should not be used while pregnant, trying to conceive or breastfeeding.
08 Monitoring
What is usually monitored
Parameters that trials and product information track. A clinician decides what applies to an individual.
- 01Full skin check by a doctor or dermatologist, with photographs of moles, before and after any exposure
- 02Any mole that changes size, shape or colour, or any new mole — seek urgent assessment
- 03Blood pressure and heart rate
- 04Severe headache, visual disturbance or confusion (possible encephalopathy) — emergency
- 05Muscle pain with dark urine (possible rhabdomyolysis) — emergency
- 06An erection lasting more than four hours — emergency
- 07Report any adverse effect to the national regulator (Yellow Card in the UK)
09 Combinations
What is known about combining it
Notes on pairing with other compounds in the directory: whether the combination has been studied in people, and where mechanisms overlap.
PT-141 (bremelanotide)
No human studies
Overlap · Both are melanocortin agonists — bremelanotide is a metabolite of Melanotan II — so the mechanism is duplicated.
Combining them stacks the same receptor activity with additive nausea, blood-pressure rise, pigmentation and (in men) prolonged-erection risk. There is no rationale and no data.
Kisspeptin
No human studies
Overlap · Both are marketed online for libido.
No data on the combination; kisspeptin adds unstudied hormone-axis stimulation to a compound with its own serious safety signals.
Semaglutide
No human studies
Overlap · Both suppress appetite and cause nausea.
No data on the combination; tolerability is likely to be worse, and Melanotan II's appetite effect is not a studied weight-loss mechanism.
Tirzepatide
No human studies
Overlap · Both suppress appetite and cause nausea.
No data on the combination; tolerability is likely to be worse.
Discuss any proposed combination with a qualified healthcare professional.
10 Source considerations
Supply, quality and legitimacy
How the compound reaches people in practice, and what that means for product quality.
- 01There is no legal, pharmaceutical-grade Melanotan II anywhere; every product is manufactured and sold illegally, with no GMP oversight.
- 02Analyses of seized tanning products have found wrong doses, unidentified impurities and bacterial contamination; injecting or spraying them adds infection and immune risks to the drug's own.
- 03Regulators (MHRA, TGA, FDA and others) have published explicit warnings; the MHRA's advice to anyone using Melanotan II injections or nasal sprays is to stop.
- 04Nasal sprays are marketed as a 'safer' alternative; they deliver the same drug, with the same systemic effects, and are equally unregulated.
11 Questions for your clinician
Take these to your appointment
Specific to this compound. The personal assessment adds questions drawn from your own history and medicines.
- 01If I have used Melanotan II, can you examine my skin and document my moles for future comparison?
- 02Do I have any cardiovascular, kidney or clotting history that makes the reported adverse events more likely for me?
- 03If sexual function is my real concern, what licensed, properly studied options exist?
- 04If tanning or appearance is my goal, what are the safe alternatives, and is a melanoma-risk assessment worthwhile?
- 05How do I report side effects I have already experienced?
The personal assessment tailors this list to your responses.
12 Alternatives
Compounds with stronger evidence or firmer regulatory footing
Listed for overlapping goals. Whether any is appropriate depends on your history — the assessment maps that for you.
13 References
Sources behind this record
Regulator documents and peer-reviewed publications used to derive every grade and statement above.
- 01Dorr RT et al. Evaluation of Melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study. Life Sci 1996;58:1777–1784
- 02Wessells H et al. Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study. J Urol 1998;160:389–393
- 03Wessells H et al. Effect of an α-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction. Urology 2000;56:641–646
- 04TGA — Don't risk using tanning products containing melanotan
- 05MHRA — FOI 24/274: side-effect reports and regulatory position on Melanotan II products
- 06FDA — Certain bulk drug substances for use in compounding that may present significant safety risks (Melanotan II entry)
The Peptide Checkup provides educational information and a structured summary of published research and regulatory status. It is not medical advice, does not diagnose or treat any condition, and does not replace a consultation with a qualified healthcare professional.
Personal assessment
Check Melanotan II against your history
Seven minutes of structured questions about your goal, history and medicines, mapped against this record by a deterministic, clinician-reviewable rules engine. The report tells you when not to buy.