Two compounds cover the tanning application: Melanotan II for speed and broad melanocortin activation, Melanotan I (afamelanotide, approved as Scenesse for EPP) for cleaner pigmentation-only signalling. Both share one non-negotiable: UV exposure is required for the tan to develop - the peptides predispose melanocytes to make eumelanin, but UV is what triggers the actual response. “Tan in a vial, no sun” is marketing.
For the receptor-level explanation see Melanocortin Map; for the day-by-day MT-II ramp see MT-II Loading Protocol.
The two compounds, head to head
| Variable | Melanotan II | Melanotan I (afamelanotide) |
|---|---|---|
| Receptor profile | MC1R + MC3R + MC4R + MC5R (broad agonist) | MC1R-selective (with some MC4R activity) |
| Tanning speed | Fast (visible at 1–2 weeks) | Slower (3–4 weeks to comparable shade) |
| Nausea | Common, dose-dependent | Rare |
| Libido shift | Yes (MC4R-driven) | Minimal |
| Appetite suppression | Mild but consistent | Negligible |
| Mole darkening / new mole risk | Real, expected | Real but generally less pronounced |
| Typical dose | 100 mcg ramp → 500 mcg/day load | 1 mg/day load (3–4x MT-II dose for similar effect) |
| Cost (grey market) | Lower | Higher (3–4x more material per cycle) |
| Approved channel | None | Scenesse for EPP (US, EU) |
UV is the mechanism, not the obstacle
- Without UV the protocol fails. Melanocyte stimulation increases melanin capacity; UV oxidises melanin and produces the visible tan. MT-II + no sun usually gives a grey-tinged complexion or no visible change.
- SPF still applies. Enhanced melanin response isn’t the same as enhanced UV protection. Sun damage accumulates regardless of pigmentation. SPF 30+ on the face; accept that body pigmentation will arrive faster than face pigmentation because of the SPF differential.
- 20–30 min sessions, 2–3x per week. Standard moderate-exposure tanning cadence. Doubling up on UV doesn’t double the response; it doubles the burn risk.
- Tanning beds vs sun. Both activate melanocytes. Beds give controlled UV-B / UV-A ratios; sun gives a wider spectrum including UV-C-tinged scattered radiation at altitude. Bed protocols are more reproducible.
Pre-protocol checklist
- Photographic mole map at year zero. Non-optional for either compound. Both compounds darken existing moles and may precipitate new ones; a photographic baseline is what makes the annual dermatology review readable. Five minutes once a year versus a missed early-stage finding is a trivial trade.
- Skin type assessment. Fitzpatrick I (very fair, burns never tans) responders less reliably to either compound. Fitzpatrick II–IV are the highest-yield population. Fitzpatrick V–VI rarely use these compounds because the baseline pigmentation is already where MT-II / MT-I would push it.
- Any history of melanoma or atypical naevus syndrome. Hard contraindication for both compounds. The melanocyte-stimulation mechanism is exactly what isn’t safe in that context.
Decision guide
- Goal: fast tan, willing to manage nausea / libido / appetite
side-effects?
→ MT-II loading protocol. Full ramp in MT-II Loading Protocol. - Goal: tan with fewer off-target effects, willing to wait
longer / pay more?
→ MT-I. 1 mg/day for 1–2 weeks loading, then 1–2x per week maintenance. - Female user sensitive to nausea / autonomic flush?
→ MT-I is the better default. The selectivity for MC1R cuts most of the off-target signalling that drives MT-II’s side- effect profile. - Erythropoietic protoporphyria (EPP)?
→ Approved-channel Scenesse via the standard medical pathway. Not a grey-market peptide question. - History of melanoma, dysplastic naevus syndrome, or
Fitzpatrick I with extensive sun damage?
→ Off the table. The mechanism is the contraindication. - Tested athlete?
→ MT-II is in the WADA grey zone (S0 / S2 mimetic catch-all); MT-I is approved as Scenesse but only for EPP. Default to "treat as banned" without TUE pathway.
Representative stacks
Stack 1 - MT-II tanning protocol (default)
- MT-II ramp: 100 mcg/d → 250 mcg/d → 500 mcg/d over 2–3 weeks
- UV exposure 20–30 min, 2–3x per week, starting from week 1
- Antihistamine 1 h pre-injection during loading (cetirizine 10 mg or loratadine 10 mg)
- Maintenance: 500 mcg–1 mg once weekly once target shade achieved
- Full runbook in MT-II Loading Protocol
Stack 2 - MT-I cleaner profile
- Melanotan I 1 mg SC daily for 1–2 weeks loading
- UV exposure 20–30 min, 2–3x per week, starting from week 1
- Maintenance: 1–2 mg once or twice weekly
- Expect 3–4 weeks to reach the shade MT-II reaches in 1–2; the cost trade is the cleaner side-effect profile
Stack 3 - Vacation prep / pre-trip base tan
- MT-I 1 mg/day SC starting 2 weeks before travel
- Tanning bed 2–3x per week during the loading window
- Maintain SPF discipline at the destination - the base tan reduces burn risk but doesn’t replace SPF
What stops people
- Skipping UV. The most common reason MT-II / MT-I "doesn’t work" in user reports. Without UV, the pigment doesn’t express on the skin in a useful way.
- Skipping the loading ramp on MT-II. 500 mcg cold first dose produces vomiting and treatment-discontinuing nausea. The ramp is short; respect it.
- Underdosing MT-I and concluding it doesn’t work. MT-I is 3–4x less potent than MT-II per weight; users accustomed to 250 mcg MT-II often underdose MT-I at the same number and get no visible response.
- Stacking MT-II + PT-141 close together. Both central melanocortin agonists; stacking at full dose increases nausea and BP load without proportional benefit. See Stacking Safety Quick Reference.
- Missing the dermatology baseline. A year of MT-II / MT-I use without a pre-protocol mole map makes the annual review much harder to read. Five minutes once is worth it.
- Sourcing problems. Both compounds are counterfeited. MT-I particularly because the higher per-cycle dose makes ingredient-cost shortcuts attractive. Skin response after the loading window is the practical assay - if no visible darkening at all, the product or protocol has a problem. See Sourcing and Verification.
Monitoring
- Photographic mole survey. Year zero, then annual. Same lighting, same poses. Document any new moles or significantly darkened existing moles for the dermatologist review.
- Skin shade photography. Weekly during loading and monthly during maintenance, for self-tracking. Same lighting, same body site (forearm dorsum is a stable reference area).
- Resting BP. Mainly relevant if the user is also on PT-141; both compounds raise BP transiently and the cumulative effect can stack.
- Annual dermatology visit. Especially after the first year of use. The mole map plus the dermatologist’s eye is the meaningful safety signal.
Cross-references
- Melanocortin Map - receptor-level explanation of MT-II vs MT-I selectivity.
- MT-II Loading Protocol - day-by-day runbook for the MT-II ramp + UV pairing.
- Skin and Hair - GHK-Cu and the broader skin-quality framing; tanning is adjacent but distinct.
- Libido and Arousal - for users where the MC4R libido side-effect of MT-II is actually the goal rather than a tradeoff.
- Sourcing and Verification - counterfeit risk on both compounds.