Melanotan-2
A synthetic copy of the hormone that switches on tanning.
Small human trials found it darkened skin without sun exposure and triggered erections in men with erectile dysfunction. It has never been approved by any regulator.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Suggested dose
0.25 – 0.5 mg
Compound profile
Scientific & efficacy data
Cosmetic
Peptide profile
Limited human trials
Melanotan-2
0.25 mg (250 mcg) · Once daily
Molecular formula
C50H69N15O9
- Mol. weight
- 1024.18 g/mol
- CAS number
- 121062-08-6
- PubChem
- 92432
- Developed · 1991
- Victor J. Hruby and Mac E. Hadley
University of Arizona
Amino acid sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2Tanning Efficacy
Increased skin colour in 2 of 3 healthy men in the only published tanning trial, measured both by a reflectance instrument and by eye, one week after 5 subcutaneous doses [1]. No larger tanning trial has been published.
Sexual Function
Erections without any sexual stimulation in 17 of 20 men with erectile dysfunction across placebo-controlled crossover trials [4]. In the psychogenic group, tip rigidity above 80% averaged 38.0 minutes versus 3.0 minutes on placebo (p=0.0045) [6]. Reported sexual desire rose after about 7 in 10 melanotan-2 doses (13 of 19, 68%) versus about 2 in 10 placebo doses (4 of 21, 19%) [4].
Tan Longevity
In the only trial that measured how long colour lasts, increased pigmentation was still present in 2 of 3 men one week after dosing stopped [1]. Persistence beyond that is community-reported and has not been measured in any published melanotan-2 trial.
Dosing
How much do I take?
0.25 – 0.5 mg
0.25 – 0.5 mg
Covers all 3 documented dose levels · timing · dose-adjustment guidance.
Suitability
Is this right for me?
Best for achieving a natural-looking tan & reducing sun exposure time
Best for
Fair-Skinned Individuals Who Struggle to Tan
If you're the type who burns before you bronze, MT-2 can be a game-changer. It works by telling your skin cells to produce more melanin—the pigment that creates a tan. People who normally can't tan often see the most dramatic results.
Those Wanting to Reduce Sun Exposure
MT-2 means you need far less UV exposure to develop and maintain a tan. A few minutes of sun or a brief tanning bed session goes much further. This could potentially reduce your cumulative UV damage over time.
Year-Round Tan Maintenance
Unlike a natural tan that fades quickly, MT-2 tans last longer and can be maintained year-round with minimal upkeep. Many users find they can keep their summer color through winter with just weekly maintenance doses.
Those Experiencing Low Libido
MT-2 has significant effects on sexual arousal and function in both men and women. While PT-141 is more targeted for this purpose, some users appreciate getting tanning and libido benefits from one peptide.
Consider alternatives if
Do not use if
Use with caution if
Not sure?
Compare Melanotan-2 with similar peptides to find the best fit for your goals.
Administration
How do I use it?
Subcutaneous injection · Nasal spray
Route
Subcutaneous injection (just under the skin)—this is the most common and effective method for MT-2
Best sites
Covers reconstitution · step-by-step technique · storage · a sample daily schedule.
Safety
Is it safe?
5 common side effects · 3 serious
Human safety data for melanotan-2 comes from small trials totalling about 23 men, plus a handful of published case reports.
In the phase-I study of 3 healthy men, mild nausea was reported at most dose levels, and the 0.03 mg/kg dose caused grade II drowsiness and fatigue in 1 of the 2 men who reached it — which is why 0.025 mg/kg was the dose carried forward [1].
Across 20 men with erectile dysfunction given 0.025 mg/kg, severe nausea occurred in about 1 in 8 (12.9%) [4].
In the psychogenic erectile-dysfunction trial, nausea, stretching and yawning, and reduced appetite were each more common on melanotan-2 than on placebo, though none required treatment [6].
Beyond the trials, single case reports describe rhabdomyolysis (muscle breakdown that can injure the kidneys) after a 6 mg injection [9], ischaemic priapism needing surgery [10], melanoma in a 20-year-old woman who used it alongside sunbeds [8], and mucosal melanoma in a 22-year-old woman who used a nasal spray version [11].
A case report shows that something happened in one person; it cannot show how often it happens.
Melanotan-2 was developed at the University of Arizona [2][3]. The published human evidence is small: a phase-I study in 3 healthy men [1] and erectile-dysfunction crossover trials totalling 20 men [4][6][7]. No published trial dosed for longer than two weeks [1].
No human pharmacokinetic study was located — searches across PubMed, the full PubChem record and ClinicalTrials.gov returned melanotan-2 data only in rats, mice and rabbits, with human pharmacokinetics available only for the related peptide melanotan-1.
One registered phase 2 trial, testing it alongside narrowband UV-B light for vitiligo, began recruiting in February 2026 and has posted no results [12]. Long-term skin-cancer risk has never been tested in a trial; what exists on that question is case reports [8][11].
Common side effects · experienced by some users
Facial flushing
Your face may turn red and feel warm shortly after injection. This is one of the most common effects, especially in the first week. It's caused by MT-2's effects on blood vessels.
Management: Usually subsides within 30-60 minutes. Taking MT-2 before bed helps. Flushing typically decreases significantly after the first week as your body adjusts.
Nausea
Many users feel queasy after injection, especially at higher doses or during the first week. This is the most common reason people struggle with MT-2.
Management: Start with lower doses (100-150 mcg) and work up. Take before bed to sleep through it. A light snack beforehand may help. Anti-nausea medications can be used if needed.
Darkening of moles and freckles
Existing moles, freckles, and any pigmented areas will darken along with your skin. This is expected but needs monitoring.
Management: Get a baseline skin check before starting. Monitor moles for any changes in size, shape, or color. See a dermatologist if any mole looks concerning.
Spontaneous erections (men)
MT-2 activates the same pathways as PT-141, so increased erections are common, especially during the loading phase.
Management: Usually decreases as your body adjusts. If problematic, reduce dose. Never combine with ED medications like Viagra—risk of priapism.
Drowsiness and fatigue
Many people feel tired or drowsy after injection, likely related to MT-2's effects on the nervous system.
Management: This is why evening dosing is recommended. Use it to your advantage—inject before bed and let it work while you sleep.
Less common
These typically resolve with continued use or dose adjustment.
Stop and seek help if
- Any mole shows concerning changes (growth, irregular borders, color changes, bleeding)
- You develop new moles that appear atypical or concerning
- Nausea or flushing remains severe beyond the first week
- You experience priapism or prolonged erection
- Any signs of allergic reaction (difficulty breathing, significant swelling)
- You've achieved your desired tan and completed your cycle
Melanotan-2 is not FDA approved and is considered a research compound. The long-term effects on skin cancer risk are not definitively known. Regular dermatological monitoring is essential for anyone using MT-2. This information is educational only—consult a healthcare provider before use.
With other peptides
- Caution:PT-141 (Bremelanotide) — Both act on melanocortin receptors. Don't use on the same day—effects may compound unpredictably. PT-141 is more targeted for sexual function.
- Safe:BPC-157 — No known interaction. Can be used together safely for general wellness benefits. Inject at different sites.
- Safe:GHK-Cu — Safe combination. GHK-Cu supports skin health through different mechanisms, complementing MT-2's tanning effects.
- Safe:Growth hormone peptides — Generally safe to combine. Separate injection times by at least 30 minutes.
With medications
- Caution:Erectile dysfunction drugs (Viagra, Cialis, Levitra) — NEVER combine—serious risk of priapism (dangerous prolonged erection). Wait at least 24-48 hours between MT-2 and ED medications.
- Caution:Blood pressure medications — MT-2 can temporarily affect blood pressure. Monitor BP closely and inform your doctor about MT-2 use.
- Caution:Antidepressants (SSRIs) — Potential for interaction affecting sexual side effects. Use with caution and monitor your response.
- Safe:Antihistamines — Some antihistamines may help with nausea and flushing. Generally safe to combine.
With supplements
- Safe:Vitamin D — Safe and potentially beneficial. Vitamin D supports skin health and you'll need less sun exposure with MT-2.
- Safe:Antioxidants (Vitamin C, E) — Safe to combine. May offer additional skin protection.
- Safe:Tyrosine is a melanin precursor. Some believe it enhances MT-2 results, though this isn't proven. Safe to take together.
- Safe:Ginger or anti-nausea supplements — Can help manage MT-2-induced nausea during the loading phase.
Effectiveness
How do I know it's working?
Limited human trials · first signs days 1-5
Evidence level
Limited human trials
Regulatory status
Not FDA approved
Onset of effects
Moderate
(1-2 weeks)
How it works
Your skin color comes from a pigment called melanin, produced by cells called melanocytes.
When you tan naturally, UV rays tell these cells to make more melanin to protect your skin. Melanotan-2 is like a shortcut—it mimics your body's natural 'make more melanin' signal (called alpha-MSH) but is much more powerful and long-lasting.
When you inject MT-2, it activates receptors on your melanocytes, telling them to ramp up melanin production. You still need a little bit of UV to 'show' the color, but far less than normal tanning.
The same receptors that control skin color also happen to affect libido and appetite, which is why MT-2 has those additional effects.
The deeper mechanism
Melanotan-2 is a synthetic cyclic heptapeptide built from alpha-melanocyte-stimulating hormone (alpha-MSH), the body's own pigment signal. It activates melanocortin receptors MC1R through MC5R without selecting between them [3].
The tanning effect runs through MC1R on melanocytes, the pigment-making cells in skin. Switching that receptor on raises cyclic AMP inside the cell, and that rise is the signal that turns up tyrosinase and the other melanin-making enzymes, increasing eumelanin, the darker pigment.
That receptor pathway was mapped in cultured human melanocytes using alpha-MSH itself rather than melanotan-2 [5].
The effect on erection is documented directly in people: melanotan-2 produced erections without any sexual stimulation in 17 of 20 men with erectile dysfunction, which points to an action in the brain and spinal cord rather than on the penis itself [4].
The work locating which melanocortin receptors carry that signal, and the appetite-suppressing signal, was done in rats, not in people [3].
The D-phenylalanine substitution this family of analogues carries makes them resist being broken down by enzymes in blood, which is why they act longer than natural alpha-MSH. That was shown for the parent analogue in frog skin and mouse melanoma cells, not in humans [2].
How long melanotan-2 itself lasts in a person has never been measured: no human pharmacokinetic study has been published, and in mice, clearance from the blood after injection was rapid.
What to expect
Days 1-5
What you might notice
- Facial flushing shortly after injection (very common)
- Nausea that may last 30-60 minutes (common)
- Feeling tired or drowsy (take at bedtime!)
- Increased libido or spontaneous erections (men)
- Little to no visible tan yet—melanin is building up
What's normal
- Flushing and nausea are common and usually decrease by day 5-7
- Some people feel nothing at all initially
- Existing freckles and moles may start darkening first
What's next
- Continue daily dosing during loading phase
- Get brief UV exposure (10-15 min) every few days to activate melanin
- Side effects typically improve significantly after the first week
Weeks 1-2
What you might notice
- Visible tan starting to develop, especially on sun-exposed areas
- Moles and freckles noticeably darker
- Side effects decreasing significantly
- Enhanced libido effects becoming apparent
- Possible slight appetite suppression
What's normal
- Tan develops gradually, not overnight
- Different body areas may tan at different rates
- Face and arms often show color first
What's next
- Continue daily dosing until you reach desired color
- Regular brief UV exposure speeds results
- Monitor moles for any concerning changes
Weeks 3-4 and beyond
What you might notice
- Your tan reaching its peak depth
- Very minimal side effects at this point
- Color appearing on areas that rarely get sun
- Long-lasting tan that fades very slowly
What's normal
- You may have reached your genetic tanning potential
- Side effects should be minimal or gone
- Tan persists well between doses
What's next
- Switch to maintenance dosing (2-3 times per week)
- Occasional UV exposure maintains color
- Many users maintain year-round tan with just weekly doses
Signs it's working
Tanning Response
- Gradual darkening of skin, especially sun-exposed areas
- Freckles and moles becoming darker
- Tan developing faster than normal with UV exposure
- Tan lasting longer and fading more slowly
- Even areas that rarely get sun developing some color
Sexual Health Effects
- Increased libido or sexual interest
- Improved erectile response (men)
- Enhanced arousal (women)
- Spontaneous erections (men)—indicates the peptide is active
Other Effects
- Reduced appetite (common side effect that some find beneficial)
- Decreased side effects over time (shows adaptation)
- Consistent results with maintenance dosing
Not seeing results? Common reasons
- Not getting any UV exposure—MT-2 produces melanin but you need some UV to 'activate' it and see the tan
- Degraded peptide from improper storage—check if solution is clear and properly refrigerated
- Dose too low—some people need the full 500mcg to see results
- Unrealistic expectations—MT-2 won't make you darker than your genetic potential allows
- Not enough time—full results take 2-4 weeks of consistent loading
- Poor quality peptide from unreliable source—always verify with third-party testing (COA)
Key research
Clinical trials
Tested in people
1 registered study, 1 still enrolling.
By phase
A trial spanning two phases is counted in both, so these can sum above the total. Observational studies carry no phase.
What kind of research
About 60 people took part in the studies that actually administered Melanotan-2. Observational studies analyse the records of people already taking it — nobody was given anything for the study, so they are counted separately and cannot show cause and effect.
Most recent
Melanotan II (MT-II) as an Adjunct to NB-UVB Phototherapy for Repigmentation in Stable Nonsegmental Vitiligo
Hudson Biotech
Sources: ClinicalTrials.gov, the EU Clinical Trials Information System and ISRCTN, deduplicated so a study registered twice is counted once. A study is counted when Melanotan-2 is named as an intervention; studies that only mention it in passing are not.
Questions
Frequently asked
Do I still need sun exposure with Melanotan-2?
Yes, but much less than normal. MT-2 increases melanin production, but some UV exposure helps 'activate' and darken the melanin. Most users find 10-20 minutes of sun or a short tanning bed session every few days is enough. The good news is you're getting tan with far less UV exposure than traditional tanning.
Will MT-2 work on very fair skin that normally burns?
Actually, this is where MT-2 shines most dramatically. People with fair skin who normally burn before they tan often see the most impressive results. MT-2 helps your skin produce the protective melanin that you'd normally struggle to make. However, you're still increasing your genetic melanin capacity—you won't become as dark as someone with naturally dark skin.
Is the tan from MT-2 different from a natural tan?
The tan is real melanin, just like a natural tan. However, MT-2 tans tend to have a slightly different hue—some describe it as a bit more 'warm' or 'golden.' The tan also lasts much longer than a natural tan because your skin is actively maintaining higher melanin levels, not just responding to UV damage.
Why does MT-2 cause nausea and how can I reduce it?
MT-2 activates receptors throughout your body, including in areas that affect nausea. The good news: it almost always improves after the first week as your body adjusts. Tips to reduce it: start with lower doses (100-150mcg), inject before bed, take with a light snack, and stay hydrated. Ginger supplements can help too.
Can women use Melanotan-2?
Absolutely. MT-2 works the same way for both sexes when it comes to tanning. Women may experience enhanced libido as a side effect, similar to men. The main considerations are the same: avoid during pregnancy/breastfeeding and monitor moles regularly.
Will my existing moles become dangerous?
MT-2 will darken existing moles and freckles—that's expected. There's no conclusive evidence that MT-2 causes melanoma, but the honest answer is we don't know the long-term effects. Anyone using MT-2 should get a baseline skin check before starting and regular follow-ups. Stop immediately if any mole changes shape, size, or color in concerning ways.
How long does an MT-2 tan last?
Much longer than a natural tan. With maintenance dosing (once or twice weekly), many users maintain their tan year-round. If you stop completely, the tan will gradually fade over 1-2 months, but this is slower than a natural tan fading because your body has genuinely increased melanin production.
Can I use MT-2 with self-tanner?
Yes, you can combine them. MT-2 creates real melanin (a biological tan), while self-tanners create surface color (DHA reacting with dead skin cells). Some people use self-tanner while waiting for MT-2 to kick in during the loading phase. Just be aware that moles darkened by MT-2 won't be covered by self-tanner.
Ready for the protocol?
Every dosing tier, administration route, timing note, and dose-adjustment rule for Melanotan-2, on one page.