Melanotan II
Non-selective melanocortin receptor agonist
Unapproved cyclic melanocortin agonist with small early human studies showing pigmentation and sexual-response effects, alongside significant safety and product-quality concerns.
Reference dose
250–500 mcg daily
Source-specific educational reference, not an individualized recommendation.
Reference schedule
Daily · 1–4 weeks
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This page gets detailed quickly.
Profiles include evidence, formats, units, source-specific reference amounts and, where relevant, device details. If any of those terms are unfamiliar, do not guess your way through them. Start with a Personalised Guide and we will put the foundations in the right order for you.
At a glance
Class
Melanocortin agonist
A cyclic alpha-MSH analogue with activity at multiple melanocortin receptors.
Human trials
Small early studies
Pigmentation and sexual-response effects were demonstrated in limited cohorts.
Regulatory status
Not FDA approved
No approved tanning or sexual-health product contains Melanotan II.
Major practical risk
Unlicensed products
Identity, purity, dose accuracy and sterility can be uncertain.
What it is
Melanotan II is a synthetic cyclic analogue of alpha-melanocyte-stimulating hormone developed to produce potent melanocortin-receptor activity.
Its pigmentation and sexual-response effects were demonstrated in early human studies, but the compound itself was not developed into an approved medicine.
Research focus
How it works
Melanotan II is a cyclic alpha-MSH analogue that activates multiple melanocortin receptors. Human studies from the 1990s and early 2000s showed increased pigmentation and erectogenic effects, but the compound was never approved and modern safety characterization remains inadequate.
Important context
Melanotan II has real human pharmacology data, so calling it purely preclinical is inaccurate. The problem is that the human trials were small and early, while widespread modern use occurs through unapproved internet products with uncertain quality.
What it is studied for
Pigmentation research examined melanogenesis and whether pharmacologic melanocortin stimulation could increase tanning.
Sexual-function research examined central melanocortin pathways involved in erectile response and desire.
The molecule is also historically important because related melanocortin work contributed to development of bremelanotide, which has a separate FDA-approved indication.
More contextHuman effects are real; clinical validation and product safety are notSee the deeper context, evidence details and practical distinctions behind this profile.
A three-person phase I study found tanning effects and dose-related adverse effects. Small placebo-controlled studies in men with erectile dysfunction demonstrated erections and increased sexual desire.
Those findings do not establish a safe consumer tanning protocol. FDA now highlights immunogenicity and peptide-impurity concerns for compounded Melanotan II and cites serious published adverse-event reports.
- The original phase I study enrolled only three healthy male volunteers.
- Small erectile-function studies reported erections in many participants, with nausea, yawning and appetite effects occurring frequently.
- Published case reports describe serious events including priapism, systemic toxicity with rhabdomyolysis, posterior reversible encephalopathy syndrome and melanoma occurring in temporal association with use.
- Case reports cannot prove that Melanotan II caused melanoma, but they reinforce why uncontrolled melanocyte stimulation and unlicensed products require caution.
Why people are interested
What makes Melanotan II worth researching.
Human · phase I · n=3
Pigmentation
A very small phase I study demonstrated increased pigmentation after repeated subcutaneous Melanotan II exposure.
Human · small controlled studies
Erectile response
Small placebo-controlled studies found a strong erectogenic signal in men with erectile dysfunction, helping lead to later development of the related approved drug bremelanotide.
Human early-phase evidence
Common acute effects
Nausea, yawning, stretching, appetite suppression, somnolence and spontaneous erections were reported in early studies.
Case reports + FDA safety review
Serious safety signals
FDA cites published reports involving melanoma, PRES, sympathomimetic toxicity and priapism, while also noting immunogenicity and peptide-impurity concerns for compounded products.
Evidence
Where the evidence is strongest, and what kind of evidence it is.
Human · phase I · 3 participants
Pigmentation study
Subcutaneous doses from 0.01 to 0.03 mg/kg increased pigmentation in the tiny pilot study, with nausea, fatigue and spontaneous erections among reported effects.
Human · small controlled trials
Erectile-function studies
Placebo-controlled crossover research in men with erectile dysfunction demonstrated substantial erectogenic effects, but sample sizes were small and development did not lead to Melanotan II approval.
Not equivalent to clinical research
Modern consumer use
Internet tanning injections and nasal products are unapproved and may not match the identity, purity, concentration or handling of material used in early trials.
Case reports / pharmacovigilance
Serious adverse-event reports
Reports include priapism requiring intervention, systemic toxicity with rhabdomyolysis, PRES and melanoma temporally associated with use. These reports signal risk but do not all establish causality.
Human research
A 1996 pilot phase I study enrolled three healthy men and demonstrated tanning activity after repeated subcutaneous Melanotan II, while documenting nausea, fatigue/somnolence and spontaneous erections.
A double-blind placebo-controlled crossover study in ten men with psychogenic erectile dysfunction found clinically apparent erections in eight of ten after Melanotan II.
Subsequent small human studies also described increased sexual desire and erectogenic effects, but the development programme did not establish an approved Melanotan II product.
Preclinical research
Preclinical melanocortin research supports strong activity at receptors involved in pigmentation, appetite and central sexual-response pathways.
Mechanistic potency does not resolve the human long-term safety, carcinogenic-risk or product-quality questions relevant to unsupervised consumer use.
Reference dosing
Reference amount, schedule and conversion.
A reference amount is only useful when you know the formulation, concentration and delivery device it belongs to. Do not transfer a vial amount into a pen, a pen click count into another pen, or a syringe-unit number into a different concentration.
01
Identify the format
Vial, reusable cartridge pen, prefilled multi-dose pen or single-dose autoinjector.
02
Confirm concentration
Know the total peptide amount and liquid volume or the manufacturer/vendor concentration.
03
Understand the units
Keep mg/mcg, mL and syringe units or device clicks separate.
04
Then use the reference
Only convert a known reference amount with the calculator that matches the actual device.
Source-specific reference
250–500 mcg daily
Daily · 1–4 weeks
The 250–500 mcg daily range is a Pep Report research reference. It is not an FDA-approved routine dose, and published research has also used study-specific weight-based amounts.
Calculator connection
Choose the calculator that matches the actual formulation. The calculator converts numbers you already know; it does not choose the target amount.
For a single-peptide research vial, the calculator can convert a labelled vial amount and reconstitution volume into concentration. It cannot verify vial identity, purity, sterility or whether a target amount is safe or clinically appropriate.
Storage
Start with the format. Then verify the exact product.
Rule of thumb, not a product instruction
Storage belongs to the exact formulation. Generic advice can orient you, but the label, pharmacy directions or formulation-specific stability data should determine the final temperature and usable-life limits.
Pens
Treat a pen as a finished drug-device product: protect it from unnecessary heat and light, do not freeze unless the exact label explicitly permits it, and use that device's own unopened and in-use storage window.
Vials
Treat dry and reconstituted vials as different stability states. Refrigeration after mixing is common for some formulations but is not a universal peptide rule.
Product-specific notes
There is no FDA-approved Melanotan II product label establishing validated consumer storage or stability conditions.
Storage claims from research-product vendors should not be assumed to establish pharmaceutical-grade stability.
Practical reference
Formats
Research vial / injection products
Unapproved nasal products are also marketed
Reconstitution & units
Adding liquid changes concentration, not total peptide mass.
A calculator cannot verify that an unapproved vial actually contains the stated amount or even the stated compound.
The vial calculator is available only for concentration arithmetic on a single-peptide vial.
The historical human research doses are not an approved target amount and should not be used as a consumer dosing recommendation.
Safety, status & open questionsOpen the practical cautionsMelanotan II is not an FDA-approved tanning or sexual-health medicine. Early human studies show biological activity, but they do not provide the safety, manufacturing-quality or long-term evidence expected for an approved consumer treatment.
Open questions
Long-term safety has not been established in a modern adequately powered development programme.
Case reports linking Melanotan II use with melanoma are not sufficient to prove causation, but melanocyte stimulation and UV exposure make dermatologic surveillance concerns biologically relevant.
Products sold online can differ substantially in purity, identity, concentration and route of administration.
There is no approved dose, schedule or product specification for consumer tanning use.
Regulatory notes
Melanotan II is not FDA approved.
FDA identifies compounded Melanotan II as a substance that may present significant safety risks, including potential immunogenicity related to aggregation or peptide impurities.
As of September 2026 FDA plans additional Pharmacy Compounding Advisory Committee review of Melanotan II before the end of February 2027.
Practical notes
Nausea, yawning, stretching, appetite suppression, fatigue/somnolence and prolonged spontaneous erections were reported in early human studies.
Priapism requiring emergency or surgical treatment has been reported after unlicensed use.
A confirmed Melanotan II exposure has been reported with sympathomimetic toxicity, rhabdomyolysis and renal dysfunction.
PRES and melanoma have appeared in published case reports temporally associated with Melanotan use; causality varies by report and should not be overstated.
Unapproved injectable products add sterility, identity, impurity and concentration risks.
Common mistakes
Calling Melanotan II entirely preclinical despite published human trials.
Treating the early phase I dose range as a validated modern tanning protocol.
Assuming Melanotan II is the same approved product as bremelanotide/PT-141.
Claiming melanoma case reports prove direct causation rather than describing them as safety signals.
Assuming calculator precision verifies an unlicensed vial's contents.
Common questions
Does Melanotan II actually have human research?
Yes. Small early studies demonstrated pigmentation and sexual-response effects, but they were not large enough to establish modern long-term safety or support approval.
Is Melanotan II FDA approved for tanning?
No. There is no FDA-approved Melanotan II tanning product.
Is Melanotan II the same as PT-141?
No. They are related melanocortin agonists, but bremelanotide/PT-141 is a distinct molecule with a specific FDA-approved prescription indication.
Why does this page still allow the vial calculator?
Only because Melanotan II is commonly sold as a single-peptide research vial. The calculator performs concentration arithmetic and does not recommend a target dose or verify product quality.
Related peptides & blends
References
Melanotan II phase I pigmentation study
PubMed · 1996
Melanotan II in psychogenic erectile dysfunction
PubMed · 1998
Melanocortin agonists and sexual response — human studies
PubMed · 2000
FDA — potential significant safety risks in compounded Melanotan II
U.S. FDA · 2026
Melanotan II injection resulting in systemic toxicity and rhabdomyolysis
PubMed · 2012
Melanotan tanning injection and acute ischemic priapism
PubMed · 2021