Nonselective melanocortin receptor agonist; synthetic cyclic alpha-MSH analogue

Melanotan II

aka Melanotan-II · MT-II · MT-2

Evidence grade

Preliminary human data

for tanning and erections

User score everyone · n = 57

US FDA Not approved checked 2026-11-13

WADA 2026 Likely prohibited (S0) by class rule · checked 2026-11-13

EU Ireland's HPRA identifies Melanotan 2 as unregulated and detains illegally supplied products; an EMA authorization was not found. · checked 2026-11-13

Goals: Libido & sexual health · Skin & hair Compare with another peptide →

User reports

approximate — combined from two independent Reddit reads

Men 45–60

0 men aged 45–60

No reports in this group yet.

All men

9 men

small sample · n = 9

Outcome positive 6 of 9 · mixed 3 of 9

Benefits skin 8 of 9 · erection 3 of 9 · hair 3 of 9 · less appetite 2 of 9 · energy 1 of 9 · fat loss 1 of 9 · libido 1 of 9 · sleep 1 of 9

Side effects skin darkening 5 of 9 · nausea 3 of 9 · flushing 2 of 9 · insomnia 2 of 9 · priapism 2 of 9 · fatigue 1 of 9 · hair shedding 1 of 9 · injection site 1 of 9 · low mood 1 of 9 · tingling / numbness 1 of 9

Why stopped goal reached 1 of 9

Stopped 1 of 9 Used with other compounds 0 of 9

Everyone

57 people

Positive: 37 of 57 (65%)
Mixed: 11 of 57 (19%)
Negative: 9 of 57 (16%)
Unclear: 1 of 57 (2%)

Benefits reported of 57

Benefits reported (n = 57)
Item	Reports
Skin	46 of 57 (81%)
Less appetite	5 of 57 (9%)
Erection	4 of 57 (7%)
Hair	3 of 57 (5%)
Libido	3 of 57 (5%)
Mood / anxiety	2 of 57 (4%)
Energy	1 of 57 (2%)
Fat loss	1 of 57 (2%)

Side effects reported of 57

Side effects reported (n = 57)
Item	Reports
Skin darkening	20 of 57 (35%)
Nausea	9 of 57 (16%)
Flushing	7 of 57 (12%)
Other	3 of 57 (5%)
Fatigue	2 of 57 (4%)
Injection site	2 of 57 (4%)
Insomnia	2 of 57 (4%)
Priapism	2 of 57 (4%)

Why people stopped of 57

Stopped 7 of 57 (12%) Used with other compounds 2 of 57 (4%)

User reports are anecdata, not evidence: self-selected, unverified, often combined with other compounds.

In their words

“It makes me feel sick every time I take it.”

side effectM · r/Melanotan2
“The erections never stop and always happen a couple of hours after taking it.”

positiveM · r/Melanotan2
“I quit mt2. I developed multiple new moles”

negativer/Melanotan2
“I didn’t even see decent results until 2ish months in.”

positiver/Melanotan2
“Although I'm darker, my skin looks a little “dirty”. My moles are more pronounced... It made me darker… but also more aged in my opinion.”

side effect45, sex not stated · r/Melanotan2
“In 14 days of a low dose it gave me a really good tan and my red beard turned black.”

positiveM · r/moreplatesmoredates
“I quit mt2. I developed multiple new moles, my back in now covered in dark freckles & normal moles got dark.”

negativer/Melanotan2
“Since my first cycle with it 10+ years ago I almost never burn. It's like I now have a built in sunblock now.”

positiver/moreplatesmoredates

Read summaries and method notes

Read 1. No verified male self-report with a stated age of 45–60 was identified in the coded sample. Among the two explicitly identifiable men, both described tanning and increased erections alongside unwanted effects. Across all 11 coded users, tanning was the dominant reported benefit, while nausea, darkened moles or freckles, and flushing were the recurring concerns. One long-term user described six years of use with persistent post-dose nausea; another user reported that visible tanning took approximately two months. These are selected, verified anecdotes from four accessible threads, not a complete survey of Reddit users or evidence of clinical safety.

Read 2. No man stating an age of 45–60 (a 45-year-old of unstated sex found darker but "dirtier, more aged" skin after three weeks). Men (n=9): 6 positive, 3 mixed — tanning, sunburn protection, darker beard hair — but also erections/priapism at high doses (1,500–2,500 mcg), post-injection nausea, flushing and fatigue. Everyone (n=54, 21 threads): 36 positive; the main reason to stop is hyperpigmentation — darker moles, new freckles, melasma. Pigment builds in 2–4 weeks with brief sun exposure.

Note 1. Verified selected self-reports only. Questions about planned use were excluded. Skin_darkening records unwanted mole, freckle, or excessive pigment changes rather than intended tanning. No qualifying male aged 45–60 was established. Age and sex were not inferred from subreddit membership, photographs, or usernames. Doses are historical user reports, not recommendations.

Note 2. A 45-year-old and a 50+ vitiligo user did not state sex and were counted only in everyone. Melanotan 1-only reports and a Metin2 gaming hit were excluded.

Each read counted people independently. Overlap between the two reads is estimated from shared threads and removed; counts are approximate. How we count.

Summary

Synthetic cyclic heptapeptide α-MSH analog. Non-selective MC1R/MC3R/MC4R/MC5R agonist. Tanning + sexual function + appetite suppression. Serious safety flags: melanoma, priapism, rhabdomyolysis.

Proposed mechanism

Synthetic α-MSH analogue with truncation, D-amino acid substitution and lactam-bridge cyclization; the previously stated numerical receptor potency was not directly verified.

MC1R → melanogenesis (eumelanin synthesis) → skin darkening without UV
MC4R (hypothalamic PVN) → sexual arousal via dopaminergic/oxytocinergic pathways → erection 1-5h post-injection
MC3R/MC4R → appetite effects observed in animals; the previously stated numerical food-intake reduction was not directly verified and does not establish human weight loss
MC5R → sebaceous gland activity increase

Non-selectivity remains relevant to bremelanotide too: its label describes activation of multiple melanocortin receptors, including MC1R, so it did not simply “solve” non-selectivity.

Safety

Nausea, yawning, fatigue and spontaneous erections
Priapism and serious systemic toxicity reports
Pigmentary lesions and melanoma case reports; causation uncertain
Rhabdomyolysis and kidney injury reports
Immunogenicity and product-quality concerns
Measured dose inconsistency in nasal products; tanning is not UV protection

From labels, regulators and trials. No signal in small studies ≠ safe.

Legal status

US FDANot approved

Not approved; former 503A Category 2 nomination withdrawn. FDA lists Melanotan II under nominated-but-withdrawn substances and retains significant safety concerns; this is not Category 1 or approval. Not on the July 23–24, 2026 PCAC agenda, so no July vote applies; a completed later review outcome was not found. Source

checked 2026-11-13

WADA 2026Likely prohibited (S0)

Prohibited (S0, non-approved pharmacological substance; class-based interpretation, not a named listing). Source

checked 2026-11-13

EU

Ireland's HPRA identifies Melanotan 2 as unregulated and detains illegally supplied products; an EMA authorization was not found. Source

checked 2026-11-13

Evidence C tanning and erections

C stands. A 3-person tanning pilot and two 10-man crossover studies; real biological activity, tiny samples, no confirmatory programme. Serious case reports exist but do not amount to demonstrated net harm, so not F.

Human trials · 3

PMID 86374021996Single-blind alternating saline/active phase 1 pilot 3 people

Healthy men

Pigmentation increased in two participants; nausea, fatigue and spontaneous erections occurred. Source
PMID 96798841998Double-blind placebo-controlled crossover RCT 10 people

Men with psychogenic ED

Clinically apparent erections in 8/10 men; early physiological proof of concept. Source
PMID 110186222000Double-blind placebo-controlled crossover RCT 10 people

Men with ED and organic risk factors

Erections after 12/19 active injections versus 1/21 placebo injections; these denominators count injections, not participants. Source

Bar length = trial size on a log scale.

Dose ranges

Reported ranges from labels and studies, with context. Not a recommendation.

clinical trial
0.01–0.03 mg/kg subcutaneously in the three-person phase 1 escalation study Source
clinical trial
0.025 mg/kg subcutaneously per active administration in the organic-ED crossover study Source

Editorial ratings EDITORIAL

Editors’ judgement, 0–5. Opinion, not data; separate from grade and user score.

Not rated yet.

Sources

Reddit threads read · 22

3 further sources on commercial or non-primary hosts not listed.

Research checked 2026-11-13.