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Melanotan II7 residues (approx.)MDHFRWKEach bubble = one amino acid. Size = residue mass. Color = chemical class.Uses closest standard amino acids for non-standard residues.Also known as: MT-II, MT-2, Melanotan 2
Roughly 80 to 90 percent of users report nausea during the first week. That number alone tells you Melanotan II (MT-II) is pharmacologically active, not a grey-market placebo. This synthetic analog of alpha-melanocyte stimulating hormone hits five melanocortin receptors at once, producing a visible tan, a noticeable libido boost, and mild appetite suppression from a single peptide. It completed Phase 1 and small Phase 2 human trials but never advanced further. Dorr and colleagues tested it in 1996 [1], and Wessells confirmed pro-erectile activity in a double-blind crossover a couple years later [2]. The loading-and-maintenance approach used today comes from community consensus, not a prescribing label.
Eighty to ninety percent of people who inject this peptide feel nauseous within the first three days. That fact gets buried under tanning photos, but it matters. Melanotan II (MT-II, CAS 121062-08-6) is a cyclic heptapeptide analog of alpha-melanocyte stimulating hormone. It binds MC1R through MC5R non-selectively, which explains both its versatility and its side-effect burden. MC1R activation drives melanogenesis. Your skin darkens without proportional UV exposure, and the effect persists for weeks after you stop because melanin itself has a slow turnover cycle. MC4R activation produces the sexual arousal, the appetite suppression, and most of the nausea. MC3R and MC5R contribute to appetite modulation and exocrine gland effects. The clinical data is real but thin. Dorr's 1996 Phase 1 trial [1] established tolerability and tanning response. Wessells ran a double-blind placebo-controlled crossover in men with psychogenic erectile dysfunction (n=10)[2] and confirmed erection response. No Phase 3 trial was ever conducted. No regulatory body has approved MT-II for any indication. Community experience fills the gap. Over 500 identifiable Reddit threads across r/steroids, r/peptides, and r/malegrooming document consistent tanning outcomes within 7 to 14 days of daily loading. A 2024 British Journal of Dermatology qualitative study (n=28) captured the broader user experience, including an 8 percent rate of anxiety and panic symptoms. Five published melanoma cases, one renal infarction, and one rhabdomyolysis event sit in the literature. MT-II is a research chemical with genuine pharmacological effects and genuine risks.
Alpha-MSH normally binds melanocortin receptors to regulate pigmentation, appetite, and sexual arousal. MT-II mimics that signaling, but its cyclic structure and D-phenylalanine substitution make it more potent and metabolically stable than native alpha-MSH. Plasma half-life sits around 1 to 2 hours based on Dorr's Phase 1 data [1]. MC1R is the tanning receptor. When MT-II binds it, melanocytes ramp up melanin production and transfer melanin granules to surrounding keratinocytes. Skin darkens over days, not hours, because the visible effect depends on melanin distribution across the epidermis. UV exposure accelerates and deepens the result by activating melanocytes that MT-II has already primed. MC4R handles the libido and nausea. Activation in hypothalamic circuits increases sexual arousal and erectile function; activation in the area postrema triggers the nausea that most users experience during loading. Tolerance to the nausea builds over 7 to 10 days through receptor desensitization. Appetite suppression also runs through MC4R and MC3R pathways. MC5R contributes to exocrine gland signaling, though its clinical relevance during MT-II use is less clear. The non-selective binding profile is exactly why MT-II produces such a wide range of effects from one injection. PT-141 (bremelanotide), which was derived from MT-II, was engineered for MC4R selectivity and earned FDA approval for that reason. MT-II remains the broader, less refined tool.
MT-II produces reliable tanning via MC1R activation and pro-erectile effects via MC4R; established in Phase 1 and small Phase 2 human trials. Never completed full clinical development. No approved dosing standard exists.
Dorr et al. 1996 Phase 1 (PMID 8637402); Wessells et al. 1998 double-blind crossover in psychogenic ED (PMID 9679884)
No Phase 3 RCTs. No regulatory submission. Maximum safe cumulative dose unknown. All dosing is extrapolated from small trials and case series. Five published melanoma cases (as of 2025). One renal infarction case (PMC7148395). One rhabdomyolysis case (PMID 23121206).
Highly effective tanner for Fitzpatrick I–II skin types; significant libido/erection enhancement. Strong nausea burden during loading limits adherence. Mole darkening causes anxiety. Sildenafil combination widely practiced but increasingly flagged as dangerous.
Science and community agree on core tanning and libido effects and general loading/maintenance structure. Diverge on dosing granularity (community uses lower starting doses than early trials), risk tolerance (community widely combines with sildenafil despite priapism signal), and maintenance rationale (community understands melanin persistence; some early trials misattributed to peptide half-life).
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 250mcg | Daily |
| Moderate | 500mcg | Daily |
| Aggressive | 1mg | Daily |
Start at 100 to 250 mcg for the first few days and inject before bed. Nausea is almost guaranteed during loading, and sleeping through it is the simplest solution. Increase by 250 mcg every 3 to 5 days only once you're tolerating the current dose. Reconstitution math for a 10 mg vial with 2 mL bacteriostatic water: that gives you 5,000 mcg per mL, or 5 mcg per unit on a U-100 insulin syringe. So 250 mcg equals 5 units (0.05 mL), 500 mcg equals 10 units (0.10 mL), and 1,000 mcg equals 20 units (0.20 mL). The thing most beginners miss is that UV exposure matters. MT-II primes your melanocytes, but you still need 10 to 15 minutes of sun or UV exposure during loading to activate melanin and get even pigmentation. Without it, tanning will be patchy and weighted toward areas that already have more melanocytes (face, arms, freckles). Store lyophilized powder at 2 to 8 degrees Celsius. After reconstitution, refrigerate and use within 30 days. Never use nasal spray formulations; a 2025 case report [6] documented oral mucosal melanoma in a 22-year-old using MT-II nasally.
Prolonged continuous MC4R activation leads to receptor desensitization. Nausea and other MC4R-mediated side effects do diminish with sustained dosing (acute desensitization), but melanocyte response to MC1R may also attenuate with prolonged use. Community consensus supports loading for 2–4 weeks, transitioning to low-frequency maintenance, then cycling off entirely for 1–3 months before reloading. There is no clinical trial data directly studying cycling protocols: rationale is extrapolated from receptor pharmacology and community observation.
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Expected: Visible tan in 7–14 days with daily UV exposure; 1–2 Fitzpatrick grade darkening by week 3
Monitor: Dermatology baseline recommended if >5 moles or Fitzpatrick I. Monitor new or changing moles monthly. Check blood pressure if combining with any vasoactive agents.
Draw 2 mL of bacteriostatic water into a syringe and inject it slowly into the vial, aiming down the glass wall. Let it dissolve; don't shake.
This gives you a concentration of 5,000 mcg per mL, or 5 mcg per unit on a U-100 insulin syringe. For a 250 mcg dose, draw to the 5 unit mark (0.05 mL). For 500 mcg, draw to 10 units (0.10 mL).
Pinch a fold of skin on your abdomen or thigh and insert the needle at a 45-degree angle.
Inject slowly, then withdraw and apply light pressure with an alcohol swab. Rotate injection sites.
Nausea and flushing peak 15 to 30 minutes post-injection, and sleeping through them is the easiest management strategy.
Once your tan reaches the desired level, switch to maintenance at 250 to 500 mcg, one to two times per week.
Use within 30 days. If the solution appears cloudy or contains particles, discard it.
Nasal bioavailability estimated lower than SC; doses used in community (≈1–2 mg per spray) are uncontrolled and poorly characterized
A 2025 case report (PMID 40210573) documented oral mucosal malignant melanoma in a 22-year-old woman who used MT-II nasal spray. This route bypasses sterile injection but introduces uncontrolled mucosal MC1R activation. No clinical dose-response data exists for intranasal MT-II. Not recommended.
Combining MC4R agonism (pro-erectile) with PDE5 inhibition dramatically increases priapism risk. Multiple community reports of 4+ hour erections requiring emergency treatment. Five severe hypotension/syncope cases reported in 2026 Clinical Toxicology literature.
Do not combineMT-II renal infarction case (PMC7148395) involved thrombotic mechanism. Anticoagulant interaction is theoretically relevant: unclear directionality. No formal interaction data. Use with caution; monitor renal function.
MT-II causes transient blood pressure changes via MC4R autonomic effects. Additive hypotension possible with antihypertensive agents, particularly at higher doses.
Pricing updated 2026-04-09
Priapism is the side effect that demands the most respect. At higher doses, MT-II can produce sustained erections lasting over 4 hours, and this is a documented medical emergency requiring intervention [3]. Combining MT-II with PDE5 inhibitors like sildenafil or tadalafil significantly increases that risk. Multiple community reports describe 4+ hour erections that ended in emergency departments. Do not combine these agents. Nausea hits 80 to 90 percent of users during the loading phase. It peaks on days 1 through 3 and correlates directly with dose. Starting at 100 to 250 mcg and injecting before bed lets you sleep through the worst of it. Tolerance builds over 7 to 10 days through MC4R desensitization. Some users pre-treat with ondansetron 30 minutes before injection. Nausea that persists beyond the first week usually responds to a 50 percent dose reduction. Facial flushing and warmth affect roughly 50 to 60 percent of users during loading. This is an MC4R autonomic effect, and it resolves as tolerance develops. Mole darkening is expected from MC1R activation. Every existing pigmented lesion gets darker, and this causes justified anxiety. At least five published melanoma cases are associated with MT-II use (Hjuler et al. 2014)[4]. Most involved pre-existing risk factors, but the association is documented. Anyone with dysplastic nevi, a personal or family history of melanoma, or FAMMM syndrome should not use this peptide. Take baseline photos and compare monthly with a dermatologist. Renal infarction through a thrombotic mechanism was reported in one case (PMC7148395) at a cumulative dose of 27 mg over 6 months. Rhabdomyolysis occurred at a single supratherapeutic dose of 6 mg, with CPK reaching 17,773 IU/L [5]. Both events are rare but medically serious. A 2024 BJD qualitative study (n=28) found that approximately 8 percent of users experienced anxiety or panic symptoms. Spontaneous erections at unpredictable times are common during loading and can be socially disruptive. Contraindications include melanoma history, multiple atypical moles, FAMMM syndrome, skin cancer of any type, pregnancy or breastfeeding, cardiovascular disease, uncontrolled hypertension, autoimmune skin conditions, and renal disease or coagulation disorders. If you develop a new, asymmetric, or rapidly growing mole, stop use and see a dermatologist immediately. If an erection lasts more than 4 hours, seek emergency care. If you experience muscle pain with dark urine or flank pain, go to the ER.
Verify Melanotan II dosing and safety with a second opinion
MT-II is sold exclusively as a research chemical with zero regulatory oversight. No FDA, EMA, or TGA approval. No mandatory testing for purity, potency, or sterility. The "Barbie drug" media cycle drove mass non-research use of unverified products. Multiple case reports of adverse events may be partly attributable to impure or misdosed product. Australia moved toward Schedule 9 (prohibited substance) classification.
| Test | When | Target |
|---|---|---|
| Full skin/mole exam (ABCDE criteria) | Before first use; monthly during use; 3 months post-discontinuation | No new, asymmetric, or rapidly growing lesions |
| Blood pressure | Before first dose; periodically during loading (first 2 weeks) | <140/90 mmHg at rest |
| Basic metabolic panel (BMP): creatinine, BUN | Before use if cumulative dose will exceed 10 mg; every 3 months during prolonged use | Creatinine within normal range; no unexplained rise >0.3 mg/dL from baseline |
| CPK (creatine phosphokinase) | If experiencing unexplained muscle pain or dark urine | <1,000 IU/L; CPK >10,000 = medical emergency |
MC1R activation darkens existing pigmented lesions. At least 5 published melanoma cases associated with MT-II use (most with co-risk factors). Early detection is critical.
MC4R activation affects autonomic tone; transient blood pressure changes documented
Renal infarction case (PMC7148395) occurred at 27 mg cumulative (~6 months at maintenance). Baseline renal function establishes safety threshold.
Rhabdomyolysis documented at supratherapeutic dose (6 mg single dose; CPK 17,773 IU/L: PMID 23121206)
Nausea is most common during initial doses: start at 250mcg. Facial flushing and mild appetite suppression may occur. No visible tanning yet.
Skin darkening begins, especially in areas with higher melanocyte density (face, arms, existing freckles). Libido increase often noticed. Nausea typically fades.
Noticeable tan develops. Moles may darken: monitor closely. Transition to maintenance dosing (500mcg 1-2x/week). Sexual function effects stabilize.
Tan reaches desired level. Minimal UV exposure helps activate and deepen pigmentation. Maintenance dose sustains color. Side effects are generally mild or absent at this stage.
Tan fades gradually over 1-3 months as melanin turns over naturally. Sexual function effects diminish within days of stopping. No known withdrawal effects.
Days 1 through 3 (loading): Side effects hit hardest before any visible change. Nausea affects 80 to 90 percent of users, especially at doses above 250 mcg. Flushing, warmth, and facial redness are common. Men often experience spontaneous erections. Appetite drops. No visible tanning yet because melanin takes days to reach the skin surface. Inject before bed to sleep through the worst of it. Days 4 through 10 (loading): Skin darkening becomes visible, starting in areas with higher melanocyte density like the face, arms, and existing freckles. Libido increases typically show up by days 5 through 7. Nausea is significantly better but not completely gone. Moles get noticeably darker, and this is where most first-timers start worrying. Expected, but monitor closely. Weeks 2 through 4 (loading to maintenance transition): A real tan develops. Most users transition to maintenance dosing around week 2 or 3, dropping from daily injection to 250 to 500 mcg once or twice weekly. Sexual function effects level out. Side effects are minimal at maintenance doses. Mole darkening continues. Weeks 4 through 12 (maintenance): Tan stays put with weekly or bi-weekly injections. The peptide itself clears in 1 to 2 hours, but melanin deposited in the skin lasts 4 to 12 weeks before natural cell turnover removes it. Maintenance keeps melanocytes active. Many users drop to once weekly. Some cycle off for 1 to 2 months and reload. Post-discontinuation: The peptide clears from plasma in hours. Tan typically lasts 6 to 10 weeks. Sexual effects return to baseline within 2 to 3 days. No withdrawal symptoms have been reported. Some users note mood normalization after stopping.
MC1R activation begins melanin synthesis; MC4R drives nausea, flushing, spontaneous erections. No visible pigmentation change yet: melanin takes days to surface.
Nausea is most intense on days 1–3, especially with doses above 250 mcg. Flushing, warmth, facial redness common. Appetite suppression noticed. Most people inject before bed to sleep through it.
Melanin granules distributed to keratinocytes. Skin darkening begins in high-melanocyte areas (face, arms, freckles). MC4R adaptation reduces nausea severity.
Noticeable skin darkening, especially in sun-exposed areas. Libido increase often noticed by day 5–7. Nausea significantly better but not gone. Moles visibly darker: common source of anxiety.
Full melanin loading of skin. UV exposure now accelerates and deepens pigment. Maintenance dosing (1–2×/week) sufficient to sustain MC1R signaling as melanin turns over.
Noticeably tanned skin. Most users transitioning to maintenance around week 2–3. Sexual function effects stabilize. Side effects minimal at maintenance doses.
Melanin half-life in skin ~4–12 weeks; maintenance injections re-stimulate melanocytes to replace lost melanin. No accumulation of peptide itself (t½ ~1–2 hours).
Tan maintained with weekly or bi-weekly injections. Many users reduce to 1×/week or less. Some users cycle off for 1–2 months then reload.
Peptide clears in hours. Melanin deposited in skin persists 4–12 weeks per natural keratinocyte turnover. Libido returns to baseline within days of stopping.
Tan typically lasts 6–10 weeks. Sexual effects gone within 2–3 days of last dose. No withdrawal symptoms reported. Some users note mood normalization after stopping.
Source: Estimated from phase-I data (Dorr et al. 1996 PMID 8637402); cyclic structure confers t½ ~1-2h
Loading the interactive decay curve.
Melanotan II has no FDA, EMA, or TGA approval for any indication. It is sold exclusively as a research chemical. Multiple regulatory agencies have issued consumer warnings against its use, and Australia has moved toward Schedule 9 (prohibited substance) classification. The World Anti-Doping Agency (WADA) prohibits MT-II under the S2 class (peptide hormones and growth factors). Athletes subject to anti-doping testing should not use it. No compounding pharmacy pathway exists for MT-II. All available product comes from research chemical vendors. Quality varies widely. Request HPLC certificates of analysis showing purity at 98 percent or above, with mass spectrometry confirmation. Prefer vendors with third-party testing. This content is for educational and research reference purposes only. It does not constitute medical advice. Consult a qualified healthcare provider before using any research compound. Peptide Schedule does not sell, distribute, or endorse the purchase of any unregulated substance.
Peptide Schedule Research TeamReviewed Apr 202611 Citations
