Melanotan I vs Melanotan II: Which Is Safer for Tanning?
Should I use melanotan I or melanotan II for tanning?
Melanotan I is the safer tanning peptide and it scores higher, 6.2 against 4.6. Both darken skin through the same receptor. Melanotan II hits three more receptors, which is where its nausea, its erection effect and its worse case record come from. Neither is approved, and both need mole surveillance.
- Melanotan I 6.2 and worth trying, melanotan II 4.6 and neutral. That is a wide gap for two peptides sold off the same vendor page.
- Both tan by activating MC1R. Melanotan I is selective for it. Melanotan II also activates MC3R, MC4R and MC5R.
- Those extra receptors are not a bonus for a tanning buyer. They are the nausea, the flushing, the appetite drop and the spontaneous erections.
- Melanotan II's case record includes melanoma, rhabdomyolysis, PRES, renal infarction and ischemic priapism. Melanotan I's does not.
- Price barely separates them. Melanotan I is an ESTIMATE of $38 to $129 a month, melanotan II an ESTIMATE of $25 to $55, both from unlicensed vendors.
- Melanotan I's clinical evidence is real but it comes from a prescription implant in a rare blood disorder, not from the vial a cosmetic buyer is injecting.
- Both darken existing moles. Full-body mole mapping before, dermatology checks after, on either one.
At a Glance
Melanotan I (Afamelanotide)
- Efficacy 4.2
- Breadth 3.0
- Evidence 4.4
- Speed 3.8
- Durability 3.1
- Bioindividuality 4.7
- Safety Risk 3.0
- Side Effects 2.6
- Cost 3.7
- Effort 2.7
- Opportunity Cost 2.3
- Dependency 1.6
- Reversibility 2.3
- Skin Beauty
- Antioxidant
- Cold Heat Tolerance
- Immune Function
MC1R-selective alpha-MSH analog. Tans through one receptor and stops there. BioHarmony 6.2, worth trying.
Melanotan II
- Efficacy 3.8
- Breadth 3.2
- Evidence 3.0
- Speed 4.2
- Durability 2.0
- Bioindividuality 3.0
- Safety Risk 3.7
- Side Effects 3.8
- Cost 2.5
- Effort 3.0
- Opportunity Cost 2.8
- Dependency 2.0
- Reversibility 2.3
- Skin Beauty
- Libido
- Body Composition
- Antioxidant
Non-selective melanocortin agonist hitting MC1R through MC5R. BioHarmony 4.6, neutral tier.
Head-to-Head Verdict
| Use Case | Winner | Rationale |
|---|---|---|
| Skin Beauty | Melanotan I (Afamelanotide) | Melanotan I 7.2 against melanotan II 6.4, and this is the row a tanning buyer is shopping. In generalized vitiligo, afamelanotide reached 48.64% repigmentation with narrowband UV-B against 33.26% for phototherapy alone by day 168 (Lim 2015). Melanotan II tans too (Dorr 1996), but its score is capped by the safety problems that ride along. |
| Antioxidant | Melanotan I (Afamelanotide) | Melanotan I 6.8 against melanotan II 5.0. This use case is skin-specific UV protection, not systemic redox, and melanotan I is the only side with a controlled photoprotection endpoint: 69.4 hours of pain-free direct sun exposure against 40.8 on placebo in the US arm (Langendonk 2015). Melanotan II gets partial credit for the same pigment mechanism with none of the regulated evidence behind it. |
| Cold Heat Tolerance | Melanotan I (Afamelanotide) | Melanotan I 5.5 against melanotan II 1.5, one of the widest gaps here. Read it narrowly: this is sun and UV tolerance in photosensitive people, not sauna or cold adaptation. A five-person solar urticaria study found improved minimum urticarial dose across 300 to 600 nm after a 16 mg implant (Haylett 2011). Melanotan II has no controlled human data on this at all. |
| Immune Function | Melanotan I (Afamelanotide) | Melanotan I 5.2 against melanotan II 1.5. Melanocortin signaling is anti-inflammatory, and a small Hailey-Hailey case series reported lesion clearance after two implants (Biolcati 2014). The score stays modest because this is skin-localized dermatology, not an immune RCT base. Melanotan II has nothing comparable. |
| Libido | Melanotan II | Melanotan II 6.1 against melanotan I 1.5, the only large gap running the other way. In men with organic erectile dysfunction, MT-II produced erections after 12 of 19 injections against 1 of 21 placebo doses (Wessells 2000). For a tanning buyer this is a side effect, not a feature. The same MC4R activity produces the nausea, and ischemic priapism is on the case record (Mallory 2021). |
| Body Composition | Melanotan II | Melanotan II 5.0 against melanotan I 1.5. Melanocortin neurons suppress feeding, which is the mechanism behind the appetite drop users report (Fan 1997). That is a rodent and mechanism argument. No human fat-loss trial supports MT-II, so treat this row as plausibility rather than a protocol, and note the appetite effect arrives whether or not you wanted it. |
| Kidney Function | Melanotan I (Afamelanotide) | Both score 1.5, so the subratings call this even and the case evidence does not. Melanotan II has a published renal infarction case with a literature review behind it (Peters 2020) and rhabdomyolysis after a 6 mg injection (Nelson 2012), which is a kidney event by another route. Melanotan I carries neither. Equal floor scores, one-sided harm record. |
| Longevity | Tie | Both score 1.5 and neither has longevity data. The honest reading is that chronic use is the least defensible pattern for either one. Melanotan I's controlled evidence covers seasonal treatment in a diagnosed condition, and melanotan II's melanoma case report (Hjuler 2014) is exactly the signal that repeated cosmetic cycling makes hardest to defend. |
Cost Comparison
| Intervention | Monthly Cost | Notes |
|---|---|---|
| Melanotan I | $38 to $129 | ESTIMATE, priced 2026-09-08, research-chemical channel, at a variable microgram-to-milligram loading dose that is not clinically validated. A 10 mg vial lists $38 to $43 (Biotech Peptides, Core Peptides). A cosmetic cycle burns about one vial a month at maintenance and up to three while loading. No purity guarantee comes with any of it.The one approved product, prescription SCENESSE (afamelanotide), is a specialist implant for erythropoietic protoporphyria and costs orders of magnitude more. It is not what a cosmetic buyer is purchasing, and it is not what this figure prices. |
| Melanotan II | $25 to $55 | ESTIMATE, priced 2026-09-07, research-chemical channel, at a variable dose. A 10 mg vial from a mid-tier research vendor runs $25 to $45, and a community loading cycle uses roughly one vial a month plus about $10 of bacteriostatic water, syringes and swabs. There is no approved product anywhere, so this is a vendor price rather than a pharmacy price. |
| The difference | Melanotan I runs about $13 to $74 a month more | Both are ESTIMATES, both are the same kind of unlicensed vendor, and the gap is small enough that price should not decide this. At the low end you are comparing $38 against $25. At a heavy loading cycle you are comparing $129 against $55.A few dollars a week is the wrong variable to optimize when the two products differ by three receptors and an entire case-report literature. If the melanotan I price is the reason you are leaning toward melanotan II, buy neither and use a sunscreen and a self-tanner instead. |
When to Switch
The two announce themselves on completely different clocks, which is the first thing to understand before judging either. Melanotan II is noticeable within about an hour, and what you notice first is usually nausea, flushing or an erection rather than color. Melanotan I gives a first signal in about two days and builds pigment over one to three weeks.
Judge melanotan II at 4 weeks and melanotan I at 8, because those are the assessment windows on each report and both reach what the reports call full effect at the same mark. Anything before that is noise. If you are eight weeks into melanotan I with no pigment change, check the vial before you raise the dose, because an unverified gray-market product is the likeliest reason a cycle does nothing.
Move from melanotan II to melanotan I when the tan is the actual goal and the nausea, appetite suppression or spontaneous erections are not wanted. That move trades a 6.1 libido subrating for a 1.5 and buys back a 0.8 point skin-beauty edge plus a much shorter list of documented harms.
Move the other way only if libido or appetite suppression is what you are after, which means you are no longer making a tanning decision at all.
My own cycle sits between those two moves: a dose or two of melanotan II to open it, then melanotan I for the rest. That is sequential rather than concurrent, and it front-loads melanotan II's speed while keeping most of the cycle on the gentler compound.
Do not run them together. They are redundant at MC1R, which is the receptor that produces the tan on both, so overlapping doubles the pigment and mole load with no second mechanism to show for it. Either direction, stop one before starting the other, and stop both immediately if a mole changes.
Who Should Pick What?
You want a tan and nothing else
Melanotan I (Afamelanotide)
Higher skin-beauty subrating at 7.2 against 6.4, higher overall score, and a receptor profile that skips the effects you did not ask for. This is the cleanest version of the decision: same goal, same channel, similar price, fewer moving parts.
Very fair skin that burns despite disciplined sun habits
Melanotan I (Afamelanotide)
This is where melanotan I's evidence actually lives. The photoprotection endpoint is controlled and specific: 69.4 against 40.8 hours of pain-free sun exposure (Langendonk 2015), plus improved light tolerance in solar urticaria (Haylett 2011). Take the question to a dermatologist first, since the trial evidence comes from prescription treatment rather than a vial.
Any suspicious, changing or atypical mole
Tie
Neither, and this is not a close call. A suspicious or changing mole is a listed contraindication on melanotan I and atypical or changing moles are listed on melanotan II. Both work by driving melanogenesis, so both darken existing nevi and make dermatologic reading harder. See a dermatologist before you consider either.
Personal history of melanoma or non-melanoma skin cancer
Tie
Neither. Melanoma history is a listed contraindication on both sides, and melanotan II carries a case report of melanoma developing in a user (Hjuler 2014). No cosmetic result justifies putting a melanocyte stimulant into someone with that history.
Libido or appetite suppression is the real goal
Melanotan II
Only melanotan II reaches those receptors: libido 6.1 against 1.5, body composition 5.0 against 1.5. Understand what you are accepting. The same MC3R and MC4R activity brings nausea, and the case record includes ischemic priapism (Mallory 2021) and rhabdomyolysis (Nelson 2012). This is not a tanning decision.
Kidney disease, uncontrolled blood pressure, seizure disorder or sickle-cell disease
Tie
Neither, and melanotan II is the harder no. Every one of those is on its contraindication list, and it has published renal infarction (Peters 2020) and PRES (Kaski 2013) cases behind the warning. Melanotan I's own list rules out severe hepatic impairment, pregnancy and lactation without clinician sign-off.
You cannot get a certificate of analysis for the vial
Tie
Neither. Both are unapproved and both require purity verification, so an untested vial is the one variable that makes every score on this page meaningless. A vial sold as melanotan I with no identity testing may be melanotan II, which converts the safer choice into the riskier one without telling you.
Research Highlights
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Mechanism Difference
These two are redundant, not complementary. Both tan by activating MC1R on melanocytes and driving eumelanin synthesis, so running them together doubles the same pigment signal with no second mechanism behind it.The difference is selectivity. Melanotan I targets MC1R and stops. Melanotan II also activates MC3R, MC4R and MC5R, which is where its libido, nausea and appetite effects come from. For a tanning buyer those receptors add unwanted effects rather than a better tan.
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Safety Comparison
The case records are not comparable. Melanotan II's verified reports include melanoma (Hjuler 2014), rhabdomyolysis after a 6 mg injection (Nelson 2012), posterior reversible encephalopathy syndrome (Kaski 2013), renal infarction (Peters 2020) and ischemic priapism (Mallory 2021).Melanotan I's documented profile is narrower: nausea in 18.5% and vitamin D deficiency in 29% of a German post-authorization cohort with 91% retention (Homey 2025). Both darken existing moles, both list melanoma history as a contraindication, and both need baseline mole mapping and repeat skin exams.
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Cost Comparison
Price does not decide this. Melanotan I is an ESTIMATE of $38 to $129 a month and melanotan II an ESTIMATE of $25 to $55, priced 2026-09-08 and 2026-09-07 against the same research-chemical channel. A 10 mg melanotan I vial lists $38 to $43.Both figures assume one vial a month at maintenance and more while loading, and neither vendor guarantees purity. The gap is $13 to $74 a month, small enough that letting it pick your compound means paying for three extra receptors to save a few dollars a week.
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Editorial Verdict
Melanotan I scores 6.2 and melanotan II 4.6, and for tanning the gap understates the case. Melanotan I wins skin-beauty 7.2 to 6.4, wins photoprotection 6.8 to 5.0, and skips the libido, nausea and appetite effects that melanotan II's extra receptors produce.Melanotan II is only the right answer when those extra effects are the actual goal, and even then its case record includes melanoma, rhabdomyolysis and PRES. If you want a tan, melanotan I is the defensible peptide. If you want a guaranteed-safe tan, there is no peptide for that.
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Evidence Quality
Melanotan I has the better evidence and it is worth being precise about whose. Its record is a Phase III trial (Langendonk 2015), a 115-patient observational study (Biolcati 2015), real-world clinical outcomes (Wensink 2020) and a vitiligo RCT (Lim 2015), almost all in a rare blood disorder at a prescription implant dose.That is not the vial a cosmetic buyer injects. Melanotan II's human base is smaller still: a pilot phase-I study (Dorr 1996) and a crossover in men with organic erectile dysfunction (Wessells 2000), plus case reports. Its evidence subscore is 3.0 out of 5.0 against melanotan I's 4.4.
Frequently Asked Questions
- Which melanotan is safer, I or II?
- Melanotan I, clearly. It activates MC1R only, so it produces the tan without the MC3R, MC4R and MC5R effects that give melanotan II its nausea, flushing, appetite suppression and spontaneous erections.Melanotan II also carries published case reports of melanoma, rhabdomyolysis, posterior reversible encephalopathy syndrome, renal infarction and ischemic priapism. Safer is not the same as safe: both darken moles and neither is approved for tanning.
- Does melanotan I tan as well as melanotan II?
- By the scoring, better. Melanotan I's skin-beauty subrating is 7.2 against melanotan II's 6.4. Both drive the same MC1R pathway, so the pigment mechanism is identical.What differs is the evidence and the noise. Melanotan I has controlled human pigmentation data, including a vitiligo trial reaching 48.64% repigmentation with phototherapy against 33.26% alone (Lim 2015). Melanotan II tans too (Dorr 1996), it just brings the extra receptors with it.
- How much does each one cost per month?
- Melanotan I is an ESTIMATE of $38 to $129 a month and melanotan II an ESTIMATE of $25 to $55, priced 2026-09-08 and 2026-09-07 through research-chemical vendors. A 10 mg melanotan I vial lists $38 to $43. Both assume roughly one vial a month at maintenance and more while loading. These are vendor prices with no purity guarantee, not pharmacy prices.
- How long until I see a tan?
- Melanotan I gives a first noticeable signal in about two days and builds pigment over one to three weeks, with full effect at 8 weeks. Melanotan II is noticeable within about an hour, though the first thing most people notice is nausea or flushing rather than color, and it reaches full effect at 4 weeks. Judge melanotan II at 4 weeks and melanotan I at 8.
- Will melanotan I give me the libido effect too?
- No, and that is the point of choosing it. Melanotan I's libido subrating is 1.5, meaning no meaningful direct human evidence. Melanotan II's is 6.1, from a crossover in men with organic erectile dysfunction where erections followed 12 of 19 injections against 1 of 21 placebo doses (Wessells 2000). If that effect is what you want, you are not making a tanning decision.
- Do either of these cause melanoma?
- Unproven, and the concern is real enough to act on. There is a published case report of melanoma in a melanotan II user (Hjuler 2014). A case report shows association, not cause.The mechanism is what should worry you: both compounds drive melanogenesis, so both darken existing moles and make dermatologic reading harder. Get full-body mole mapping before you start and repeat skin exams after. A suspicious or changing mole rules out both.
- Can I stack melanotan I and melanotan II?
- No. They are redundant at MC1R, which is the receptor producing the tan on both, so stacking doubles the pigment and mole load with no extra mechanism. Stop one before starting the other. If you are combining them to add melanotan II's libido or appetite effects on top of melanotan I's tan, you are accepting melanotan II's entire risk profile anyway.
- Is the vial I buy actually melanotan I?
- You do not know unless you test it. Both sit outside the approved supply chain, melanotan I as a gray-market research chemical and melanotan II as research-only material labelled not for human use.Purity verification is your job on both. Ask for a certificate of analysis and treat its absence as a no. A vial sold as melanotan I that is actually melanotan II hands you every side effect you picked melanotan I to avoid, and nothing on the label will tell you.
Evidence Sources
- RCT Afamelanotide for Erythropoietic Protoporphyria (2015) Phase III trial: 69.4 hours of pain-free direct sun exposure on afamelanotide against 40.8 hours on placebo in the US arm.
- Observational Long-Term Observational Study of Afamelanotide in 115 Patients with Erythropoietic Protoporphyria (2015) Long-term safety and quality-of-life data in 115 EPP patients treated with afamelanotide.
- Observational Association of Afamelanotide With Improved Outcomes in Erythropoietic Protoporphyria in Clinical Practice (2020) Real-world practice data showing increased outdoor time and improved quality of life in EPP patients.
- Observational German Cohort Study of the Short- and Long-Term Safety and Effectiveness of Afamelanotide 16 mg (2025) Post-authorization cohort reporting 91% retention, nausea in 18.5% and vitamin D deficiency in 29% of patients.
- RCT Afamelanotide and Narrowband UV-B Phototherapy for the Treatment of Vitiligo (2015) Randomized multicenter trial: greater repigmentation when afamelanotide was added to narrowband UV-B phototherapy.
- Observational Systemic Photoprotection in Solar Urticaria with an Alpha-MSH Analogue (2011) Five-person pilot: improved minimum urticarial dose across 300 to 600 nm after a 16 mg implant.
- Observational Efficacy of the Melanocortin Analogue Nle4-D-Phe7-Alpha-MSH in Hailey-Hailey Disease (2014) Small case series reporting lesion clearance after two implants, with Nrf2-related mechanisms described.
- Systematic review Pharmacokinetics and Pharmacodynamics of Afamelanotide and Its Clinical Use (2017) Review of absorption and action, with an overview of clinical use across dermatologic disorders.
- Systematic review Afamelanotide: A Review in Erythropoietic Protoporphyria (2016) Benefit-risk review of the alpha-MSH analogue in erythropoietic protoporphyria.
- RCT Effect of MELANOTAN on Melanin Synthesis in Humans with MC1R Variant Alleles (2006) Human study showing MC1R variant alleles change the melanin response to the melanotan peptide. Response is not uniform.
- RCT Evaluation of Melanotan-II, a Superpotent Cyclic Melanotropic Peptide: Pilot Phase-I Study (1996) Short low-dose subcutaneous MT-II produced measurable pigmentation, with mild nausea and spontaneous erections.
- RCT Effect of an Alpha-Melanocyte Stimulating Hormone Analog on Penile Erection and Sexual Desire (2000) Men with organic erectile dysfunction: erections after 12 of 19 MT-II injections against 1 of 21 placebo doses.
- Animal study Role of Melanocortinergic Neurons in Feeding and the Agouti Obesity Syndrome (1997) Melanocortin neurons tonically suppress feeding, which explains the appetite drop from MC4R-active compounds.
- Observational Melanoma Associated with the Use of Melanotan-II (2014) Case report linking melanoma development to melanotan II use.
- Observational Melanotan II Injection Resulting in Systemic Toxicity and Rhabdomyolysis (2012) Systemic toxicity and rhabdomyolysis following a 6 mg melanotan II injection.
- Observational Melanotan and the Posterior Reversible Encephalopathy Syndrome (2013) Posterior reversible encephalopathy syndrome in a woman after subcutaneous melanotan use.
- Observational Melanotan II: A Possible Cause of Renal Infarction (2020) Case and literature review linking MT-II to renal infarction through possible thrombotic and direct renal toxic effects.
- Observational Melanotan Tanning Injection: A Rare Cause of Priapism (2021) Acute ischemic priapism after a melanotan tanning injection, treated with penoscrotal decompression.
Glossary
Quick reference for the medical and technical terms used in this comparison.
- MC1R Melanocortin-1 Receptor
- The receptor on pigment cells that triggers eumelanin production. Both peptides activate it, and it is the only one melanotan I targets.
- MC3R Melanocortin-3 Receptor
- A melanocortin receptor involved in energy balance and inflammation. Melanotan II activates it, melanotan I does not.
- MC4R Melanocortin-4 Receptor
- The brain receptor behind melanotan II's appetite suppression and erection effects. Melanotan I skips it, which is why it lacks those effects.
- MC5R Melanocortin-5 Receptor
- A melanocortin receptor found in sebaceous and exocrine tissue. Melanotan II is non-selective enough to hit it.
- alpha-MSH Alpha-Melanocyte-Stimulating Hormone
- The natural hormone both peptides imitate. Melanotan I is a selective analog of it, melanotan II a non-selective one.
- EPP Erythropoietic Protoporphyria
- A rare inherited blood disorder causing severe pain on sun exposure. Nearly all of melanotan I's controlled evidence comes from this population.
- PRES Posterior Reversible Encephalopathy Syndrome
- A brain condition with headache, seizures and vision loss, usually reversible. Reported in a melanotan II user (Kaski 2013).
- COA Certificate of Analysis
- A lab document stating a vial's identity and purity. Required on both peptides here, since neither comes through a regulated supply chain.
- MUD Minimum Urticarial Dose
- The smallest light dose that raises hives in solar urticaria. It improved after a 16 mg implant in the Haylett 2011 pilot.
