Emerging evidence · Grade B
Melanotan 2
Melanotan II
Score
62 / 100
Effect in humans
Real
Safety
Serious concerns
Status
Unapproved
TL;DR
01
An unapproved synthetic melanocortin agonist marketed online (the 'Barbie drug') for tanning and for boosting libido and erections.
02
It genuinely works pharmacologically in humans — small trials confirm it darkens skin and produces erections and increased desire — which is exactly why it spread.
03
But it is unregulated and carries serious, documented harms: rhabdomyolysis and renal infarction, priapism (dangerous prolonged erection), severe nausea, and darkening or change of moles.
04
That mole/pigment effect is a specific concern: uncontrolled melanocyte stimulation with no dermatologic monitoring, and case reports link it to new or changing melanomas.
05
There is no approved product, no quality control, and no medical oversight — the pharmacology is real, and so are the risks.
Human pharmacology
Confirmed
tanning + erection (small RCTs)
Serious harms
Documented
rhabdo, renal infarction, priapism
Melanoma concern
Yes
mole darkening/change
Approval
None
grey-market only
Quality control
None
unregulated supply
Part 01 · How it works
Mechanism.
Melanotan II is a synthetic cousin of the hormone alpha-MSH that switches on melanocortin receptors broadly. Through MC1R it drives melanin production (tanning); through MC3R/MC4R in the brain it increases sexual arousal. Both effects are real and reproducible in people — that's not in question. The problem is that it hits these receptors without selectivity and without oversight: the same signaling that tans skin also stimulates moles, and the same arousal effect can tip into dangerous prolonged erections, alongside reports of muscle breakdown and kidney injury.
It presses several melanocortin buttons at once — tan, arousal, and, unavoidably, the pigment cells in your moles — with no dose control and no one watching. The effects are real; so is the collateral.
Non-selective melanocortin agonism
Activates MC1R (melanogenesis), MC3R/MC4R (sexual arousal, appetite), and more — broad, unselective receptor activation.
Melanogenesis
Stimulates melanocytes to produce melanin without UV exposure — and stimulates existing nevi, the basis of the melanoma concern.
Central arousal
MC4R activation in the CNS drives erections and desire (demonstrated in small human studies), and can cause priapism.
Off-target toxicity
Case reports link it to rhabdomyolysis, renal infarction, and acute kidney injury via thrombotic/direct-toxic effects.
Part 02 · Dosing & administration
How it's taken.
Community-reported · unregulatedValues below reflect commonly reported community protocols for Melanotan 2. These are anecdotal and unregulated — not clinically validated and not a recommendation. Provided for educational purposes only — this is not medical advice and not instructions for self-administration. Consult your healthcare provider before making any health decision.
Wk 1–3
0.25–0.5 mg/day
Loading — start 0.25 mg to gauge nausea, build toward ~0.5 mg daily until tan develops
TARGET
Wk 4+
~0.5 mg 2×/week
Maintenance — real frequency varies with UV exposure
·
No approved dose — figures are community protocols from unregulated supply with no purity/concentration guarantee.
·
Nausea is near-universal during loading (peaks 2–4 h post-dose); bedtime injection is the common workaround.
·
Get moles/skin checked first and monitor them: MT-2 darkens existing nevi, and there are melanoma and priapism case reports.
Need help with reconstitution?
Use the free peptide calculator for dilution, unit conversion, and injection volume.
Part 03 · Safety
Side effects, rare serious events, who shouldn't.
Common
Nausea
Often severe, especially with early or larger doses.
Frequent
Facial flushing
Transient.
Common
Spontaneous erections
An intended effect that can become excessive.
Common (men)
Darkening of moles/freckles
Direct consequence of melanocyte stimulation.
Common
Serious · rare
Rhabdomyolysis / acute kidney injury
Muscle breakdown and kidney injury, including renal infarction, in case reports.
Reported
Priapism
Prolonged erection is a urologic emergency; can cause permanent damage.
Reported
Melanoma / changing nevi
New or changing moles/melanomas linked to use; no dermatologic monitoring in grey-market use.
Reported
Product-quality risk
Unregulated supply; purity and dose unknown.
Source-dependent
Absolute · do not use
×
History of melanoma or dysplastic nevi
×
Personal or family history of skin cancer
×
Pregnancy or breastfeeding
×
Children under 18
×
Known hypersensitivity to Melanotan II or any component
×
Cardiovascular disease (may affect blood pressure)
×
Autoimmune conditions
Relative · discuss first
!
Personal or family history of melanoma or atypical moles — avoid (melanocyte stimulation)
!
Any changing or atypical mole — urgent dermatologic evaluation before/with any use
!
Cardiovascular or clotting risk — reports of thrombotic renal injury
!
Anyone unwilling to accept unmonitored serious risk — this is unapproved and unregulated
Interactions
Antihypertensives
Melanotan II can affect blood pressure; may potentiate or oppose antihypertensive effects
Moderate
PDE5 inhibitors (sildenafil, tadalafil)
Additive effects on erectile function and blood pressure; risk of hypotension and priapism
Moderate
Other melanocortin agonists (PT-141, Melanotan 1)
Additive melanocortin receptor activation; increased adverse effect risk
Moderate
Photosensitizing drugs
Increased tanning response may mask or potentiate phototoxic reactions
Minor
Labs to monitor
Dermatological Exam (Full Body Skin Check)
Baseline and every 6 months
Non-selective melanocortin agonist — monitor moles/nevi
Blood Pressure
Baseline and regularly
Melanocortin system affects cardiovascular function
CMP (Comprehensive Metabolic Panel)
Baseline and every 3 months
Liver and kidney function
CBC with Differential
Baseline and every 3 months
General safety monitoring
Part 04 · Evidence
How strong is the evidence?
62
Grade B
Grade B, Emerging — an unusual case where the score is dragged down not by weak efficacy but by safety. The human pharmacology is real (it tans and it works on libido), but it is unapproved, unregulated, and carries serious documented harms including a melanoma concern. Read the safety axis.
Mechanistic plausibility
Clear, well-understood melanocortin agonism; effects reproducible in humans.
80
Human evidence
Small human trials confirm tanning and sexual effects — but no approved efficacy program or long-term data.
55
Safety & tolerability
Serious documented harms: rhabdomyolysis, renal infarction, priapism, severe nausea, and mole/melanoma concern with no monitoring.
40
Durability
Effects fade after use; repeated dosing compounds pigment and safety risks.
55
Independence
Human effects documented across independent case reports and small studies.
62
Part 05 · Research log
Every study we cite.
We list each study with its methodology, funding source, and our quality grade. Flagged studies aren't dismissed — they're tagged so you can weigh them.
01
2000
Urology Flagged
Melanotan II on erection and sexual desire in men with erectile dysfunction
Induced erections in 12 of 19 injections (vs 1 of 21 placebo) and increased desire — but severe nausea occurred in 4 of 19 injections.
Double-blind, placebo-controlled crossover · n = 10 · Small proof-of-pharmacology study; confirms real human effect and prominent nausea.
PMID 11018622 ↗
Moderate
02
2020
CEN Case Reports Flagged
Melanotan II: a possible cause of renal infarction (case report + review)
Documents renal infarction attributed to Melanotan II and reviews prior reports of Melanotan-II-induced rhabdomyolysis and renal failure.
Case report with literature review · n = 1 · Single case plus review; establishes serious real-world harm signals.
PMID 31953620 ↗
Case-level (safety)
Evidence against
What didn't work, and where the evidence is thin.
Every publication is incentivized to tell you a peptide works. We catalogue the null results, failed trials, and mechanism limits we found in the same literature — so you can weigh them against the upside, with your provider.
01
Serious documented harms — rhabdomyolysis, renal infarction, priapism
Safety signal CEN Case Reports · 2020
Case reports link Melanotan II to rhabdomyolysis (muscle breakdown), renal infarction, acute kidney injury, and priapism (prolonged, potentially damaging erection), alongside severe nausea.
What this means: These are not minor side effects. Because the product is unregulated and unmonitored, users bear these risks with no medical safety net.
PMID 31953620 ↗
02
Uncontrolled melanocyte stimulation and melanoma concern
Safety signal Urology (mechanism) · 2000
Melanotan II stimulates melanocytes non-selectively, causing existing moles to darken, enlarge, or change — and dermatology case reports link its use to new or changing melanomas. There is no dermatologic monitoring built into grey-market use.
What this means: A drug that drives pigment cells without oversight is a poor trade for a tan. Any changing mole in a user warrants urgent dermatologic evaluation.
PMID 11018622 ↗
Part 06 · Cost & access
Where it's available, at what price.
United States
Not approved
Not an approved drug; illegal to market for human use. Sold grey-market online. No legal consumer medicine.
Grey-market; unregulated
European Union
Not approved
Not approved; sale for human use is not permitted. Grey-market only.
N/A
United Kingdom
Not approved
MHRA has warned against Melanotan II; not approved. Grey-market only.
N/A
Canada
Not approved
Not approved; grey-market only.
N/A
The Peptide Column takes no affiliate commission from any source. Melanotan II is unapproved, illegal to market for human use, and carries serious documented harms; regulators including the UK MHRA have warned against it. We link only to clinician-directed care, never to sellers, and we do not endorse its use.
Part 07 · Your appointment
Questions to bring.
01
What are the risks of using a non-selective melanocortin agonist versus selective ones?
02
Should I have a dermatological exam before and during use given mole-darkening risks?
03
What cardiovascular monitoring is advisable with Melanotan II?
04
Are there safer FDA-approved alternatives for my specific goal?
References
Every citation, numbered.
Citation list. For our editorial read of each study — including bias flags and quality grades — see the Research log above.
- 01. Melanotan II on erection and sexual desire in men with erectile dysfunction · Urology, 2000 · PMID 11018622 ↗
- 02. Melanotan II: a possible cause of renal infarction (case report + review) · CEN Case Reports, 2020 · PMID 31953620 ↗
- 03.