Melanotan II
updated
What is Melanotan II?
Melanotan II is the cyclic heptapeptide Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH2. It is distinct from the linear afamelanotide implant and from bremelanotide, even though all belong to the melanocortin family.
Melanotan II produced pigmentation and erections in very small human experiments, with nausea and other acute effects. It is not an approved tanning or weight-loss drug, and recent regulator testing found large dose variation among five identically labeled nasal bottles.
cyclic melanocortin agonist peptide
- Cyclic seven-amino-acid melanocortin agonist
- Activates MC1R, MC3R, MC4R, and MC5R
- Does not activate the ACTH-specific MC2R
- No approved tanning product
What exactly is Melanotan II?
Melanotan II is the cyclic heptapeptide Ac-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-NH2. It is distinct from the linear afamelanotide implant and from bremelanotide, even though all belong to the melanocortin family.
Receptor pharmacology · MC1/3/4/5 agonist
Receptor pharmacology study
European Medicines Agency and published receptor studies summarized in Bremelanotide assessment materials.
The receptor data place Melanotan II-class cyclic analogs at MC1R, MC3R, MC4R, and MC5R. MC2R is the ACTH-specific melanocortin receptor and is not a supported target for Melanotan II.
- Study design
- Regulatory pharmacology assessment
What has Melanotan II actually done in people?
Very small experiments found pigmentation in two of three men and erectile responses in ten-man crossover studies. They establish acute physiological responses, while their size and duration cannot define reliable tanning or overall safety.
| Experiment | Denominator | Main finding |
|---|---|---|
| Pigmentation | 3 men | Pigmentation in 2; nausea, fatigue or somnolence, and erections reported |
| Psychogenic ED | 10 men | Clinically apparent erections in 8 |
| Organic ED | 10 men; 19 active injections | Erections after 12 active injections; severe nausea after 4 |
Three-man pilot · pigmentation and acute effects
Human pilot experiment
Dorr RT et al. Life Sciences, 1996.
Three men received alternating saline and Melanotan II injections. Two showed increased pigmentation. Nausea, fatigue or somnolence, and erections were observed; three participants cannot estimate effectiveness or safety.
- Participants / model
- 3 healthy men
- Treatment
- Subcutaneous Melanotan II and saline in alternating periods
- Study design
- Small within-person pilot
Ten-man crossover · erections and nausea
Randomized crossover trial
Wessells H et al. Urology, 1998.
Eight of ten men had a clinically apparent erection after Melanotan II in a crossover experiment. Nausea, yawning, and decreased appetite were reported more often with active treatment.
- Participants / model
- 10 men with psychogenic erectile dysfunction
- Treatment
- Subcutaneous Melanotan II or placebo
- Study design
- Double-blind placebo-controlled crossover experiment
This does not establish a safe routine treatment, weight loss, or an approved indication.
Read the original sourceTen-man crossover · rigidity and severe nausea
Randomized crossover trial
Wessells H et al. Urology, 2000.
In ten men, erections occurred after 12 of 19 active injections and 1 of 21 placebo injections. Four of 19 active injections caused severe nausea. The duration above 80% tip rigidity averaged 45.3 minutes with active treatment and 1.9 minutes with placebo.
- Participants / model
- 10 men with organic erectile dysfunction
- Treatment
- Subcutaneous Melanotan II or placebo on separate visits
- Study design
- Double-blind placebo-controlled crossover experiment
Which receptors does it activate?
Melanotan II acts at MC1R, MC3R, MC4R, and MC5R. Pigmentation is linked mainly to MC1R, while central sexual and appetite effects involve other melanocortin pathways. MC2R is ACTH-specific and should not be included in its target list.
Receptor pharmacology · MC1/3/4/5 agonist
Receptor pharmacology study
European Medicines Agency and published receptor studies summarized in Bremelanotide assessment materials.
The receptor data place Melanotan II-class cyclic analogs at MC1R, MC3R, MC4R, and MC5R. MC2R is the ACTH-specific melanocortin receptor and is not a supported target for Melanotan II.
- Study design
- Regulatory pharmacology assessment
Does Melanotan II cause useful weight loss?
No reliable human weight-loss outcome appears in the cited evidence. Decreased appetite in a ten-man erectile-function experiment is an adverse-effect observation, not a weight-loss trial.
Ten-man crossover · erections and nausea
Randomized crossover trial
Wessells H et al. Urology, 1998.
Eight of ten men had a clinically apparent erection after Melanotan II in a crossover experiment. Nausea, yawning, and decreased appetite were reported more often with active treatment.
- Participants / model
- 10 men with psychogenic erectile dysfunction
- Treatment
- Subcutaneous Melanotan II or placebo
- Study design
- Double-blind placebo-controlled crossover experiment
This does not establish a safe routine treatment, weight loss, or an approved indication.
Read the original sourceWhat are the main risks and unknowns?
Nausea and erections were common enough to appear in tiny trials, with severe nausea after 4 of 19 active injections in one study. Priapism, neurological toxicity, lesion changes, immune reactions, and mislabeled product content are higher-consequence concerns with uncertain frequency.
Case reports cannot establish causation, and most did not independently verify the identity or dose of the online or compounded product used.
Ten-man crossover · rigidity and severe nausea
Randomized crossover trial
Wessells H et al. Urology, 2000.
In ten men, erections occurred after 12 of 19 active injections and 1 of 21 placebo injections. Four of 19 active injections caused severe nausea. The duration above 80% tip rigidity averaged 45.3 minutes with active treatment and 1.9 minutes with placebo.
- Participants / model
- 10 men with organic erectile dysfunction
- Treatment
- Subcutaneous Melanotan II or placebo on separate visits
- Study design
- Double-blind placebo-controlled crossover experiment
FDA safety page · Melanotan II reports
FDA safety communication
US Food and Drug Administration.
FDA lists Melanotan II among substances that may present significant safety risks in compounding and cites serious reported events including melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome, and priapism, along with immunogenicity and impurity concerns.
- Study design
- Agency safety summary of reported events and product concerns
These reports do not establish that Melanotan II caused every event or that each product contained the stated ingredient.
Read the original sourceCase reports · temporal signals, uncertain products
Published case reports
PubMed records PMID 24355990, 21564053, 22724573, 19380666, and 40210573.
The reports describe melanoma or rapid nevus changes after products sold as Melanotan I or II. They establish temporal associations and a reason for lesion surveillance, but generally do not establish what each product contained, exclude ultraviolet exposure, or prove causation. One intranasal report does not establish that the nasal route caused the lesion.
- Study design
- Published case reports
TGA 2026 · 22 to 54 mg in five bottles
Regulator laboratory alert
Australian Therapeutic Goods Administration, 17 August 2026.
TGA laboratory testing confirmed Melanotan II in five seized nasal bottles carrying the same 30 mg label. Estimated total content ranged from 22 mg to 54 mg. TGA says no Melanotan II product is in the Australian Register of Therapeutic Goods or approved there as a tanning agent.
- Participants / model
- Five seized nasal bottles from one labeled product line
- Treatment
- Laboratory content testing
- Study design
- Regulator product investigation
The finding shows a quality-control failure in these bottles, not the distribution of every product on the market.
Read the original sourceIs Melanotan II an approved tanning agent?
No. FDA lists safety concerns for compounded Melanotan II, and TGA states that no Melanotan II product is registered or approved in Australia as a tanning agent.
FDA safety page · Melanotan II reports
FDA safety communication
US Food and Drug Administration.
FDA lists Melanotan II among substances that may present significant safety risks in compounding and cites serious reported events including melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome, and priapism, along with immunogenicity and impurity concerns.
- Study design
- Agency safety summary of reported events and product concerns
These reports do not establish that Melanotan II caused every event or that each product contained the stated ingredient.
Read the original sourceTGA 2026 · 22 to 54 mg in five bottles
Regulator laboratory alert
Australian Therapeutic Goods Administration, 17 August 2026.
TGA laboratory testing confirmed Melanotan II in five seized nasal bottles carrying the same 30 mg label. Estimated total content ranged from 22 mg to 54 mg. TGA says no Melanotan II product is in the Australian Register of Therapeutic Goods or approved there as a tanning agent.
- Participants / model
- Five seized nasal bottles from one labeled product line
- Treatment
- Laboratory content testing
- Study design
- Regulator product investigation
The finding shows a quality-control failure in these bottles, not the distribution of every product on the market.
Read the original sourceStudies and sources
Three-man pilot · pigmentation and acute effects
Human pilot experiment
Dorr RT et al. Life Sciences, 1996.
Three men received alternating saline and Melanotan II injections. Two showed increased pigmentation. Nausea, fatigue or somnolence, and erections were observed; three participants cannot estimate effectiveness or safety.
- Participants / model
- 3 healthy men
- Treatment
- Subcutaneous Melanotan II and saline in alternating periods
- Study design
- Small within-person pilot
Ten-man crossover · erections and nausea
Randomized crossover trial
Wessells H et al. Urology, 1998.
Eight of ten men had a clinically apparent erection after Melanotan II in a crossover experiment. Nausea, yawning, and decreased appetite were reported more often with active treatment.
- Participants / model
- 10 men with psychogenic erectile dysfunction
- Treatment
- Subcutaneous Melanotan II or placebo
- Study design
- Double-blind placebo-controlled crossover experiment
This does not establish a safe routine treatment, weight loss, or an approved indication.
Read the original sourceTen-man crossover · rigidity and severe nausea
Randomized crossover trial
Wessells H et al. Urology, 2000.
In ten men, erections occurred after 12 of 19 active injections and 1 of 21 placebo injections. Four of 19 active injections caused severe nausea. The duration above 80% tip rigidity averaged 45.3 minutes with active treatment and 1.9 minutes with placebo.
- Participants / model
- 10 men with organic erectile dysfunction
- Treatment
- Subcutaneous Melanotan II or placebo on separate visits
- Study design
- Double-blind placebo-controlled crossover experiment
Receptor pharmacology · MC1/3/4/5 agonist
Receptor pharmacology study
European Medicines Agency and published receptor studies summarized in Bremelanotide assessment materials.
The receptor data place Melanotan II-class cyclic analogs at MC1R, MC3R, MC4R, and MC5R. MC2R is the ACTH-specific melanocortin receptor and is not a supported target for Melanotan II.
- Study design
- Regulatory pharmacology assessment
TGA 2026 · 22 to 54 mg in five bottles
Regulator laboratory alert
Australian Therapeutic Goods Administration, 17 August 2026.
TGA laboratory testing confirmed Melanotan II in five seized nasal bottles carrying the same 30 mg label. Estimated total content ranged from 22 mg to 54 mg. TGA says no Melanotan II product is in the Australian Register of Therapeutic Goods or approved there as a tanning agent.
- Participants / model
- Five seized nasal bottles from one labeled product line
- Treatment
- Laboratory content testing
- Study design
- Regulator product investigation
The finding shows a quality-control failure in these bottles, not the distribution of every product on the market.
Read the original sourceFDA safety page · Melanotan II reports
FDA safety communication
US Food and Drug Administration.
FDA lists Melanotan II among substances that may present significant safety risks in compounding and cites serious reported events including melanoma, posterior reversible encephalopathy syndrome, sympathomimetic toxidrome, and priapism, along with immunogenicity and impurity concerns.
- Study design
- Agency safety summary of reported events and product concerns
These reports do not establish that Melanotan II caused every event or that each product contained the stated ingredient.
Read the original sourceCase reports · temporal signals, uncertain products
Published case reports
PubMed records PMID 24355990, 21564053, 22724573, 19380666, and 40210573.
The reports describe melanoma or rapid nevus changes after products sold as Melanotan I or II. They establish temporal associations and a reason for lesion surveillance, but generally do not establish what each product contained, exclude ultraviolet exposure, or prove causation. One intranasal report does not establish that the nasal route caused the lesion.
- Study design
- Published case reports
Why is Melanotan II in C tier?
The C grade reflects small administered-human studies showing pigmentation and erectile responses, with no reliable long-term safety record; the identity of online products relative to the research material is uncertain.