Peptide profile · Cosmetic
Melanotan-2
A powerful synthetic peptide that mimics your body's natural tanning hormone, giving you a deeper, longer-lasting tan with minimal sun exposure while also showing surprising benefits for libido and appetite.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team
Typical dose
0.5 mg (500 mcg)
Half-life
33-36 hours
Bioavailability
High (subcutaneous injection)
Molecular weight
1024.18 g/mol
Evidence level
Limited human trials
01 · Compound profile
Scientific & efficacy data
Molecular formula
C50H69N15O9
Primary benefits
Highly effective at inducing skin darkening with minimal UV exposure—works on even the fairest skin types
Significant effects on libido and arousal in both sexes—a notable secondary benefit (or side effect)
Creates long-lasting color that persists for weeks between doses and can be maintained year-round
University of Arizona
Amino acid sequence
Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH202 · Dosing
How much do I take?
0.5 mg (500 mcg) · once daily
Subcutaneous: A small injection into the fatty layer just under the skin — the same way insulin is given.
Bioavailability High — most of the dose reaches your bloodstream, just more gradually than an IV.
Best time to take
Evening or before bed works best for most people. This helps you sleep through any initial nausea or flushing. The long half-life (33+ hours) means timing isn't critical for effectiveness.
With food?
Taking MT-2 on an empty stomach speeds absorption but may increase nausea. If nausea is an issue, try a light snack 30-60 minutes before. Once you're past the first week, food timing matters less.
If stacking
If using with other peptides, inject at different sites. MT-2 is often the only peptide people use at bedtime due to the drowsiness it can cause. Don't combine with PT-141 on the same day—both affect the same receptors.
＋ Increase if
- +You've used starting doses for a week with minimal side effects
- +You're not seeing color development after 2 weeks with some UV exposure
- +Your maintenance dose isn't holding your tan between doses
－ Decrease if
- −Nausea persists beyond the first week
- −Flushing is severe or uncomfortable
- −You're experiencing unwanted sexual side effects
- −New moles are appearing (consult dermatologist)
✓ Signs of right dose
- ✓Gradual, natural-looking tan development
- ✓Minimal nausea after the first few doses
- ✓Stable color that lasts between maintenance doses
- ✓No concerning changes to existing moles
Dosing Calculator
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03 · 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.
04 · Administration
How do I use it?
Subcutaneous injection · Nasal spray
Reconstitution — what you need
Example
If you have a 10mg vial and add 2mL of BAC water, you get a concentration of 5mg/mL (or 5000mcg/mL). So every 0.1mL (10 units on an insulin syringe) equals 500mcg of MT-2.
For a 250mcg dose at 5mg/mL concentration: draw 0.05mL (5 units on a standard insulin syringe). For 500mcg: draw 0.1mL (10 units). Many users add 2mL to a 10mg vial for easy math.
Route
Subcutaneous injection (just under the skin)—this is the most common and effective method for MT-2
Best sites
Technique
- 01Wash your hands thoroughly with soap and water
- 02Clean the injection site with an alcohol swab and let it dry
- 03Pinch about an inch of skin to create a fold
- 04Insert the needle at a 45-90 degree angle
- 05Inject slowly and steadily—rushing can increase nausea
- 06Wait 5-10 seconds before removing the needle
- 07Don't rub the site—just light pressure if needed
Storage · before reconstitution
Store your MT-2 powder in the refrigerator (36-46°F / 2-8°C) for up to 12 months or in the freezer (-4°F / -20°C) for up to 2 years. Keep in original sealed vial away from light. The powder is quite stable when stored properly.
Storage · after reconstitution
Refrigerate at 36-46°F (2-8°C) immediately after mixing. Never freeze reconstituted MT-2—it will be destroyed. Keep away from light and use within 28-30 days for best potency.
Signs of degradation
Sample daily schedule
05 · Safety
Is it safe?
5 common side effects · 3 serious
Melanotan-2 has been studied in clinical trials and shows a generally acceptable short-term safety profile when used as directed. The most common side effects—nausea and flushing—are usually temporary and decrease with continued use. However, MT-2 is not FDA approved, and long-term safety data is limited. The main safety concern is the unknown effect on melanocytes (pigment-producing cells), particularly in people with a history of melanoma or atypical moles.
MT-2 was developed at the University of Arizona and has undergone multiple clinical trials for tanning and sexual dysfunction. While short-term studies show reasonable safety, long-term effects on skin cancer risk are not definitively known. Anyone using MT-2 should get regular skin checks from a dermatologist.
Common side effects · experienced by some users
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
- !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.
- ✓BPC-157 — No known interaction. Can be used together safely for general wellness benefits. Inject at different sites.
- ✓GHK-Cu — Safe combination. GHK-Cu supports skin health through different mechanisms, complementing MT-2's tanning effects.
- ✓Growth hormone peptides — Generally safe to combine. Separate injection times by at least 30 minutes.
With medications
- !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.
- !Blood pressure medications — MT-2 can temporarily affect blood pressure. Monitor BP closely and inform your doctor about MT-2 use.
- !Antidepressants (SSRIs) — Potential for interaction affecting sexual side effects. Use with caution and monitor your response.
- ✓Antihistamines — Some antihistamines may help with nausea and flushing. Generally safe to combine.
With supplements
- ✓Vitamin D — Safe and potentially beneficial. Vitamin D supports skin health and you'll need less sun exposure with MT-2.
- ✓Antioxidants (Vitamin C, E) — Safe to combine. May offer additional skin protection.
- ✓Tyrosine is a melanin precursor. Some believe it enhances MT-2 results, though this isn't proven. Safe to take together.
- ✓Ginger or anti-nausea supplements — Can help manage MT-2-induced nausea during the loading phase.
06 · Effectiveness
How do I know it's working?
Limited human trials · first signs days 1-5
Evidence level
Limited human trials
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.
Melanotan-2 is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone (α-MSH). It acts as a non-selective agonist at melanocortin receptors MC1R through MC5R. Its primary tanning effect occurs through MC1R activation on melanocytes, triggering the cAMP/PKA signaling cascade that upregulates tyrosinase and other melanogenic enzymes, increasing eumelanin synthesis. The peptide's effects on sexual function occur primarily through MC3R and MC4R activation in the hypothalamus and spinal cord, facilitating dopaminergic and oxytocinergic pathways involved in sexual arousal. Appetite suppression is mediated through MC4R activation in the paraventricular nucleus of the hypothalamus. MT-2's cyclic structure and D-phenylalanine substitution provide resistance to enzymatic degradation, resulting in a prolonged half-life of 33-36 hours compared to minutes for natural α-MSH. This allows for practical dosing schedules while maintaining sustained receptor activation.
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
Signs it's working · Sexual Health Effects
- ✓Increased libido or sexual interest
- ✓Improved erectile response (men)
- ✓Enhanced arousal (women)
- ✓Spontaneous erections (men)—indicates the peptide is active
Signs it's working · 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
07 · 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.