Melanotan II
MT-II · MT-2 · Melanotan-2
Last updated
At a glance
Overview
Melanotan II has carved out a permanent spot in the looksmaxxing toolkit for one reason: it reliably produces a deep, year-round tan at doses most users tolerate well, and it does it faster than any amount of sunbed time alone. The community reaches for it when pale skin is the bottleneck — before a holiday, ahead of a photo shoot, or just to maintain a Mediterranean baseline through a northern winter. As a bonus, the MC4R activity that comes along for the ride produces a pronounced pro-libido and pro-erectile effect that overlaps with what PT-141 is FDA-approved for.
What makes MT-II distinctive is the pharmacodynamic leverage: plasma half-life is under an hour, but the downstream melanogenesis it triggers plays out over weeks. That means small, sub-milligram doses — dramatically lower than the 0.16 mg/kg used in the original Arizona trials — are enough to build visible pigment when paired with modest UV exposure. Run it right and you'll see color at day 7–10 and hit target shade inside a month.
"Subcutaneous administration of 0.16 mg/kg MT-II over 10 days produced significant darkening of skin in all participants, with effects persisting for several weeks following cessation." — Dorr et al., Life Sciences (1996)
The caveats matter and we'll cover them honestly. Nausea and facial flush dominate the first few injections, existing moles and freckles will darken, and anyone with dysplastic nevi or a personal/family history of melanoma should not run this compound, full stop — get a dermatologist mole map prior to initiating the protocol. Sourcing is grey-market peptide territory, so vendor selection is part of the protocol.
The rest of this page walks through the loading-vs-maintenance dose ladder, how to pair injections with UV for clean even pigment, side-effect management (including the ondansetron trick for first-dose nausea), the MT-II + tadalafil libido stack, what to expect from the tan timeline, and the mole-monitoring cadence that keeps long-term use defensible.
How Melanotan II works
MC1R Agonism and the Melanogenesis Cascade#
MT-II is a cyclic heptapeptide analog of α-MSH that binds and activates melanocortin-1 receptors (MC1R) on epidermal melanocytes. Receptor activation drives Gs-coupled cAMP elevation → PKA activation → CREB phosphorylation → MITF transcription, which upregulates tyrosinase — the rate-limiting enzyme in melanin synthesis. The downstream output is a shift toward eumelanin (the dark, photoprotective pigment) over pheomelanin. This is what produces the tan, and it's also why MT-II works in people whose native MC1R variants make them poor tanners — you're bypassing a weak endogenous signal with a superpotent exogenous one.
"Subcutaneous administration of 0.16 mg/kg MT-II over 10 days produced significant darkening of skin in all participants, with effects persisting for several weeks following cessation." — Dorr, R. T. et al. Life Sciences, 1996
Practically: the pigment change lags the peptide by days because you're waiting on transcription and melanosome transfer to keratinocytes, not on circulating drug. Plasma half-life is ~30–60 minutes, but visible darkening shows up around day 5–7 of loading and peaks around week 3–4. This is also why UV pairing matters — UV stimulates melanocyte dendricity and melanosome transfer, giving you an even, clean tan rather than the blotchy, freckle-concentrated color MT-II produces on its own.
MC4R Agonism — Libido, Erection, and Appetite#
MT-II is non-selective across MC1R/MC3R/MC4R/MC5R, and MC4R activity in the hypothalamus and spinal cord is what drives the non-pigmentary effects users notice: spontaneous erections, increased sexual desire, appetite suppression, and the characteristic yawning/stretching response.
"MC4R is the major melanocortin receptor in the brain responsible for regulating sexual function in both men and women, as demonstrated in studies using MT-II." — Hadley, M. E. Peptides, 2005
In RigiScan-monitored trials, a single 0.025 mg/kg SC dose produced clinically meaningful erectile activity in men with organic ED:
"Melanotan II administration resulted in clinically relevant erectile activity in men with organic erectile dysfunction — with a mean of 41 min of tip rigidity >80% occurring in 17 of 20 men at 0.025 mg/kg." — Wessells, H. et al. Urology, 2000
This is the mechanism the looksmaxxing community exploits when stacking MT-II with daily tadalafil — tadalafil handles the peripheral vascular piece via PDE5 inhibition, MT-II handles central desire via MC4R. The same MC4R pathway drives the appetite-suppressing side effect, though MT-II is a messy appetite tool compared to a GLP-1 or setmelanotide.
MC3R/MC5R Activity — The Nausea and Flush Profile#
The first-dose side effects — nausea, facial flushing, yawning, and transient blood pressure changes — are predominantly mediated by central MC3R/MC4R activity and peripheral MC5R effects on sebaceous and exocrine tissue. Tolerance develops quickly: most users find nausea is intense for the first 2–4 injections, then fades substantially as receptor signalling adapts.
This is why the community playbook is to dose in the evening (sleep through the peak), start at 100–250 mcg rather than the clinical 0.16 mg/kg (which is ~10 mg in an 80 kg user — wildly above what anyone actually tolerates), and keep ondansetron 4–8 mg on hand for loading. Escalating gradually lets MC4R-mediated nausea desensitize before you push the dose into the range where pigmentation accelerates.
Pigment Persistence and Nevus Darkening#
Because pigmentation is a transcriptional and structural change (new melanin synthesized, packaged into melanosomes, transferred into keratinocytes that then take ~28 days to reach the skin surface), the tan outlasts the drug by weeks to months. Cessation doesn't mean immediate fade — it means no new pigment is being driven, and existing pigment sheds with normal epidermal turnover.
The flip side is that MC1R agonism is indiscriminate across all melanocytes, including those in existing nevi, freckles, and lentigines. Moles darken universally. New nevi can appear. Case reports and dermatology literature have flagged atypical melanocytic lesions and changes in dysplastic nevi in MT-II users, which is why the hard contraindication is real and non-negotiable: do not run MT-II if you have a personal or first-degree family history of melanoma, dysplastic nevi, atypical moles, or a high total nevus count. The monitoring that matters here is dermatological, not endocrine — full-body mole mapping before starting, photographic tracking, and annual derm checks thereafter.
Vascular and Renal Considerations#
MC1R and MC5R are expressed on vascular endothelium, and MT-II produces transient increases in blood pressure and heart rate acutely post-injection, alongside flushing. In heavy users, rare but documented complications include rhabdomyolysis and renal infarction:
"We report a case of renal infarction potentially linked to melanotan II injection, highlighting this rare but serious complication documented in heavy users." — Peters, B. et al. CEN Case Reports, 2020
These are outlier events tied to aggressive dosing, not expected outcomes at community doses of 250–1000 mcg. But they are the reason uncontrolled hypertension and recent cardiovascular events are hard contraindications, and the reason sensible users keep doses in the 250–500 mcg/day range during loading rather than chasing the 0.16 mg/kg clinical protocol.
Protocol
| Level | Dose | Frequency | Notes |
|---|---|---|---|
| Low | 100–250 mcg | Once daily | Documented entry-level range |
| Mid | 250–500 mcg | Once daily | Most commonly studied range |
| High | 500–1000 mcg | Once daily | Dose in the evening during loading to sleep through peak nausea and flush. Drop to 500–1000 mcg 1–2×/week for maintenance once target shade is reached. |
Cycle length & outcomes
Documented cycle
2–6 weeks
Plateau after
6 wks
Melanotan-2 is cycled differently than almost anything else in the looksmaxxing toolkit — you're not building a hormonal response or managing suppression, you're titrating a cosmetic endpoint (skin shade) with a peptide whose pharmacodynamic tail vastly outlasts its 30–60 minute plasma half-life. The loading phase builds pigment, the maintenance phase holds it, and the cycle ends when you stop wanting to be tan.
Cycle Structure by Goal#
| Goal | Loading | Maintenance | Total Cycle |
|---|---|---|---|
| Light cosmetic tan (Fitz III–IV) | 250 mcg/day × 10–14 days | 500 mcg 1×/week | 2–4 weeks active, then indefinite maintenance |
| Deep aesthetic tan (Fitz I–II) | 250 → 500 mcg/day × 3–4 weeks | 500–1000 mcg 2×/week | 4–6 weeks active, then maintenance |
| Pre-holiday accelerated | 500 mcg/day × 2–3 weeks + UV | 500 mcg 3×/week to trip date | 4–6 weeks |
| Libido / sexual response only | — | 500–1000 mcg 4–8 h pre-session, PRN | As needed |
| Maintenance-only (already pigmented) | — | 500–1000 mcg 1×/week year-round | Indefinite |
Loading Protocol#
The first injection is a scouting dose, not a therapeutic one. Nausea and flushing are strongly dose-dependent and tachyphylactic — tolerance builds within 3–5 shots. Start at 100–250 mcg SC in the evening so you sleep through the peak. Escalate by 100–250 mcg every 2–3 days until you hit your working dose (usually 250–500 mcg daily). Ondansetron 4–8 mg 30 minutes pre-shot blunts first-week nausea if it's a problem.
Pigment lags the drug. Expect nothing visible for the first 5–7 days, early darkening at day 7–10, and your target shade by week 3–4. This is a transcriptional process downstream of MC1R → cAMP → MITF → tyrosinase, which is why the effect outlasts the peptide by weeks.
"Subcutaneous administration of 0.16 mg/kg MT-II over 10 days produced significant darkening of skin in all participants, with effects persisting for several weeks following cessation." — Dorr et al., Life Sciences (1996)
Note that 0.16 mg/kg is ~11 mg in an 70 kg adult — far above what the community runs. Looksmaxxing protocols trade raw dose for a longer loading window because nausea tolerance, not pigment ceiling, is the rate-limiting step.
UV Pairing — Non-Negotiable for Clean Color#
MT-II alone produces a muddy, uneven tan that concentrates in freckles and existing lentigines. You need a UV stimulus to distribute melanin evenly across the epidermis. Standard practice:
- Sunbed 5–10 min 3×/week during loading, or
- Natural sun 15–30 min on non-peak hours, incrementally extended.
Mineral sunscreen on the face if you don't want facial pigment racing ahead of the body. Do not try to shortcut with heavy single UV sessions — you'll burn on MT-II just as easily as off it, and burns on an MT-II-primed epidermis pigment darkly and patchily.
Maintenance Phase#
Once you hit target shade, drop to 500–1000 mcg once or twice weekly. Most experienced users plateau here for months or years. Pigment fades slowly — figure 6–10 weeks for a full loading tan to disappear after cessation, longer with intermittent UV.
There is no need to cycle off. MT-II doesn't suppress any endogenous axis, doesn't require PCT, and doesn't develop receptor tolerance at the MC1R pigment endpoint. The only reason to stop is if you want to lose the tan or if dermatological monitoring flags a nevus change.
Libido-Only Dosing#
For users running MT-II primarily for the MC4R-mediated sexual response rather than pigment, treat it as PRN rather than a cycle. 500–1000 mcg SC 4–8 hours pre-session, no loading needed. Works in both sexes.
"MC4R is the major melanocortin receptor in the brain responsible for regulating sexual function in both men and women, as demonstrated in studies using MT-II." — Hadley, Peptides (2005)
"Melanotan II administration resulted in clinically relevant erectile activity in men with organic erectile dysfunction—with a mean of 41 min of tip rigidity >80% occurring in 17 of 20 men at 0.025 mg/kg." — Wessells et al., Urology (2000)
Stacks cleanly with daily low-dose tadalafil — tadalafil handles the peripheral vascular piece, MT-II contributes central desire and spontaneous erectile activity. PT-141 (bremelanotide) is the cleaner tool if you want libido without pigment, but MT-II is what most users already have in the fridge.
Monitoring — Dermatological, Not Endocrine#
There is no bloodwork cadence for MT-II. No LFTs, no lipids, no hormone panel. The monitoring you actually need is on your skin:
- Full-body mole map with a dermatologist before your first cycle. Photograph every existing nevus. This is the single most important step and the one most often skipped.
- Re-check annually if running MT-II long-term.
- Watch for new nevi, asymmetric darkening of existing nevi, or any lesion that changes faster than the surrounding skin.
Hard contraindication: personal or first-degree family history of melanoma, dysplastic nevi, atypical mole syndrome, or a high total nevus count. MC1R agonism darkens existing nevi universally — this can mask early melanoma changes. If you're in this category, don't run MT-II. This isn't hedging; it's the one line in the MT-II protocol that doesn't bend.
Also keep an eye on renal symptoms at the higher end of community dosing:
"We report a case of renal infarction potentially linked to melanotan II injection, highlighting this rare but serious complication documented in heavy users." — Peters et al., CEN Case Reports (2020)
This is a case-report-level signal, not a common outcome, but it's a reason to stay in the 250–1000 mcg community range rather than chasing clinical-trial doses.
Onset Timing Summary#
| Effect | Onset |
|---|---|
| Nausea / flush / yawning | 30 min – 4 h post-shot |
| Spontaneous erections / libido | 1–8 h post-shot |
| Visible pigmentation | Day 5–10 of loading |
| Target tan shade | Week 3–4 of loading |
| Post-cessation fade | 6–10+ weeks |
Dose at night, load slowly, add UV, map your moles, and drop to maintenance when the mirror says you're done. That's the entire protocol.
Risks & mistakes
Common (most users)#
Most of these show up in the first 3–5 injections and fade as tolerance builds. The trick is starting low and dosing in the evening so you sleep through the worst of it.
- Nausea — the defining first-dose effect, especially above 250 mcg on a naive user. Dose before bed, eat a light meal 1–2 hours prior, and keep ondansetron 4–8 mg ODT on hand for the first few shots. Tolerance develops fast — usually gone by injection 4–5.
- Facial flushing — warm, red face 15–60 minutes post-injection. Harmless, self-limiting. Not worth mitigating.
- Spontaneous yawning and stretching — classic MC4R signature. No action needed; confirms the peptide is real and dosed.
- Spontaneous erections (men) / increased libido (both sexes) — useful for some, inconvenient for others. Shift dose timing earlier or later depending on whether you want the effect in your evening window or want to sleep through it.
- Transient appetite suppression — mild anorectic effect for a few hours post-dose. Eat before injecting if you're in a surplus.
- Darkening of existing nevi, freckles, lentigines, and areolae — universal and expected. Photograph all nevi before starting so you have a baseline to compare against (see contraindications below).
- Injection site irritation / small wheals — rotate sites across the abdomen and flanks.
"Subcutaneous administration of 0.16 mg/kg MT-II over 10 days produced significant darkening of skin in all participants, with effects persisting for several weeks following cessation." — Dorr et al., Life Sciences (1996)
Uncommon (dose-dependent or individual)#
These tend to appear above ~750 mcg/day, in users who ramp too fast, or in those with pre-existing cardiovascular issues.
- Persistent nausea / vomiting past the loading phase — you're dosing too high. Drop back to 250 mcg for a week and re-titrate slowly.
- Priapism — prolonged erection >2 hours. Uncommon at community doses but real at 1 mg+ single shots. If it happens, cut the dose by 50% going forward. An erection lasting >4 hours is an ER visit, full stop.
- Transient hypertension and tachycardia — check resting BP at baseline and during loading. If you're already running AAS and sitting at 140/90, MT-II is the wrong time to add cardiovascular load.
- Hyperpigmentation of lips, gums, palmar creases, and genitals — cosmetic, reversible over months after cessation. Back off dose or extend maintenance intervals if it bothers you.
- New nevi appearing mid-cycle — document with photos. A few new small, symmetric, evenly-pigmented spots are within expected range. Anything asymmetric, multi-colored, or >6 mm gets a dermatologist's eye, not a forum's.
- Muddy, uneven tan concentrated in freckles — not medically concerning, just a cosmetic failure mode. The fix is adding modest UV (sunbed 5–10 min 3×/week or real sun) — MC1R activation without UV stimulus distributes poorly.
Rare but serious#
- Rhabdomyolysis and acute renal injury / renal infarction — documented in case reports of heavy users. Warning signs: flank pain, cola-colored urine, sharp drop in urine output, unexplained severe back or abdominal pain. Stop immediately and go to an ER.
"We report a case of renal infarction potentially linked to melanotan II injection, highlighting this rare but serious complication documented in heavy users." — Peters et al., CEN Case Reports (2020)
- Atypical melanocytic lesions / melanoma in situ — case reports exist of melanoma diagnosed in MT-II users. Causation vs. surveillance bias is unsettled, but the mechanism is biologically plausible: MT-II darkens existing nevi and can mask the asymmetry/color changes that dermatologists look for. Any mole that changes shape, develops irregular borders, bleeds, itches persistently, or grows — stop MT-II, get it biopsied.
- Severe hypertensive response — rare, mostly in users with underlying uncontrolled HTN. Chest pain, vision changes, severe headache post-injection = stop and evaluate.
- Counterfeit / mis-labeled product reactions — the grey-market peptide space is unregulated. Unexplained severe reactions (systemic allergy, injection-site abscess, wildly unexpected effects) usually point to a sourcing problem. Stick to vendors with third-party HPLC COAs.
Hard contraindications#
These are not negotiable. Do not run MT-II if any of the following apply:
- Personal history of melanoma — any prior diagnosis, any stage.
- First-degree family history of melanoma (parent, sibling, child).
- Dysplastic nevi, atypical moles, or a high total nevus count (>50 nevi is the common dermatology threshold). MC1R agonism will darken every existing lesion and can appear to generate new ones — this destroys your ability to monitor for early melanoma changes.
- Fitzpatrick I skin with extensive sun damage / actinic keratoses — get these evaluated first.
- Immunosuppression (transplant recipients, active biologics affecting melanocyte biology).
- Uncontrolled hypertension or recent cardiovascular event (MI, stroke, unstable angina within 6 months).
Get a full-body dermatology mole check before your first injection and photograph every existing nevus. Re-check annually while running MT-II. This is the single highest-leverage action you can take — the cost is one appointment and the return is catching a problem when it's still a 2 mm spot rather than a stage III diagnosis.
Gender considerations and PCT#
Dosing is identical for men and women. Women consistently report a more pronounced pro-libido/arousal effect than men, consistent with the MC4R data underlying PT-141's FDA approval for female HSDD.
"MC4R is the major melanocortin receptor in the brain responsible for regulating sexual function in both men and women, as demonstrated in studies using MT-II." — Hadley, Peptides (2005)
Pregnancy: not studied, not appropriate during pregnancy or active attempts to conceive. Discontinue well before.
PCT: none required. MT-II does not touch the HPTA, does not suppress endogenous testosterone, and does not require any hormonal ancillaries. It stacks cleanly alongside AAS cycles, hair-loss protocols (finasteride/dutasteride, topical AR antagonists), and daily tadalafil without pharmacologic interaction — the only thing to watch is cumulative cardiovascular load if you're already running orals or high-dose AAS with elevated BP.
Stack & combine
Multipliers applied when these compounds run together. Values > 1 indicate a bonus on that axis. Tap a partner to expand the mechanism.
| Partner | Type | Lean | Fat loss | Recovery |
|---|---|---|---|---|
| synergistic | ×1.00 | ×1.00 | ×1.00 |
Pharmacokinetic conflicts, competing pathways, or compounded toxicity. Multipliers below 1 indicate the affected axis.
| Partner | Type | Lean | Fat loss | Recovery |
|---|---|---|---|---|
| antagonistic | ×1.00 | ×1.00 | ×0.90 |
FAQ — Melanotan II
Where to buy
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Research & citations
5 studies cited on this page.
Conclusion
Melanotan-2 is the go-to research peptide for anyone after an aesthetic, sustained tan with the side benefit of MC4R-driven libido enhancement. The payoff is a controlled bronze look that lasts for weeks, with or without ongoing UV — but you have to respect the loading curve, mole monitoring, and early-dose side effects.
Key takeaways:
- Start low: 100–250 µg subQ first dose to test tolerance, then ramp up by 100–250 µg every few days
- Standard loading: 250–500 µg subQ each evening with modest UV exposure; hit target shade in 2–4 weeks
- Maintenance: 500–1000 µg subQ 1–2×/week plus periodic UV for long-term results
- Most common side effects: flush and nausea (timed evening dosing + ondansetron helps), darkening of existing moles and freckles is universal
- Absolute contraindication: personal/family melanoma history or atypical/dysplastic nevi — get a derm mole check prior to initiating the protocol
- Reliable grey-market sourcing and proper reconstitution/storage are non-negotiable — don't cut corners here
If your goal is a year-round tan with an edge in libido, and you're vigilant about mole checks, MT-II is the community's proven protocol.