Melanotan II

MT-II, MT-2, Melanotan 2, "tan jab", "Barbie drug"; cyclic [Nle4, D-Phe7]-α-MSH(4-10) analog

Checked Oct 28, 2026

The short answer

Early human data for tanning

Grade C for tanning: the only controlled human tanning data are a 1996 placebo-controlled pilot in 3 men, which showed visible darkening after five low doses.

Approved?: Not approved for any use.
Safety: E, flagged: Case reports link it to melanoma, kidney infarction, muscle breakdown and priapism, and it was never taken through full safety testing or approved anywhere.

The full answer: what it is for, the dose, the units

What people take it for: People inject it to tan with less sun. It also commonly raises libido and erections and lowers appetite, because it switches on several melanocortin receptors, not only the one that darkens skin.

Does it work for tanning? C, early human data. Result: worked.

Grade C for tanning: the only controlled human tanning data are a 1996 placebo-controlled pilot in 3 men, which showed visible darkening after five low doses. It was never carried through to a full trial or approved, and it carries serious case-report harms.

No approval for any use.

Safety: E, flagged. Case reports link it to melanoma, kidney infarction, muscle breakdown and priapism, and it was never taken through full safety testing or approved anywhere.

Do not use if: Anyone with personal or family history of melanoma or atypical/dysplastic nevus syndrome, or numerous/changing moles.

Could it be placebo? The tan is visible and measured, and in the pilot pigmentation rose in the treated men and not on saline days, so a placebo effect does not explain the tanning; the libido effects were self-reported.

The dose people use, and the units to draw

The only named human doses are per kilogram of body weight: 0.01 to 0.03 mg per kg per injection in the 1996 pilot, and 0.025 mg per kg in two later erection studies. No named source gives the flat-dose gray-market protocols.

Source	Dose	How often and how	Who it was for	Link
Dorr et al. 1996 (pilot phase I, single-blind placebo-controlled)	Started at 0.01 mg per kg and raised in 0.005 mg per kg steps to 0.025 mg per kg (one man) and 0.03 mg per kg (two men); 0.025 mg per kg per day recommended for later phase I studies	Subcutaneous, once daily Monday to Friday for 2 weeks, alternating days of MT-II and saline	3 healthy men	abstract
Wessells et al. 1998 (double-blind placebo-controlled crossover, erections)	0.025 mg per kg	Injection, single doses versus vehicle placebo, erections monitored by RigiScan for 6 hours	10 men with psychogenic erectile dysfunction	abstract
Wessells et al. 2000 (review of the group's double-blind crossover studies)	0.025 mg per kg; 12.9% of subjects had severe nausea at this dose	Injection versus placebo in a crossover design, penile rigidity monitored for 6 hours	20 men with psychogenic and organic erectile dysfunction	abstract
Huberman Lab, Apr 1, 2024 (Andrew Huberman)	No dose stated	Describes the melanotan family as tanning, mood, libido and appetite peptides and warns people with melanoma to be cautious; gives no dose	General discussion of melanocortin peptides for vitality	01:15:10 (auto-transcript at podscripts.co, verify by ear)

From 0.01 mg per kg (the starting dose) to 0.03 mg per kg per injection in the 1996 pilot (Dorr), with 0.025 mg per kg the dose the later erection studies used.

The site's earlier flat doses, maintenance dose and titration steps had no named non-seller source, and no named podcast or clinician source gave a melanotan II dose. Dr. Abud Bakri's Jun 2026 Huberman Lab episode mentions melanotan only in passing, and Examine.com could not be opened (rate limited).

Reported by the named source, never prescribed by us.

How many units do I draw?

On a U-100 insulin syringe, units = 100 x dose (mg) / (vial mg / water mL). Enter your vial size, the water you add and the dose in the calculator and it does the arithmetic. Open the dose calculator

Why it might work

Subcutaneous injection
MT-II (cyclic [Nle4
Non-selective melanocortin receptor binding across MC1R-MC5R
MT-II binds all four peripheral and ce
MC1R activation on melanocytes, eumelanin synthesis
MC1R stimulation on skin melanocytes s
MC4R and MC3R activation, libido, appetite suppression, autonomic effects
Central MC4R activation in hypothalami
Melanocyte stimulation and uncharacterized melanoma risk
By driving melanocyte proliferation an

Assumed pathway, not shown in people.

Assumed mechanism: MT-II is a synthetic, cyclic, more metabolically stable analog of alpha-melanocyte-stimulating hormone (alpha-MSH). It is presumed to bind and activate melanocortin receptors non-selectively. MC1R on melanocytes drives eumelanin (dark pigment) synthesis, producing tanning, while activation of MC3R/MC4R/MC5R is the assumed basis for the off-target sexual (erectile/libido), appetite-suppressing, and autonomic/cardiovascular effects. The pigmentary mechanism is well supported by human data; calling it 'assumed' applies mainly to the breadth and dose-dependence of the systemic effects. Not an approved drug.

The trials, claim by claim

A 1996 University of Arizona pilot phase-I trial in humans showed subcutaneous MT-II produced visible tanning within roughly five low-dose injections, the first and most-cited human evidence the compound works.

Result: worked

Open-label pilot phase-I human study (Dorr RT, Lines R, Levine N, Brooks C, Xiang L, Hruby VJ, Hadley ME, 1996); small, uncontrolled, but genuine human data establishing the pigmentary effect.

PubMed: Dorr 1996 phase-I MT-II pilot (PMID 8637402)

MT-II is non-selective across melanocortin receptors (MC1R/MC3R/MC4R/MC5R), which is why the same dose that tans also commonly causes erections, nausea, and appetite loss.

Consistent across the foundational human pilot (which incidentally documented erections) and pharmacology reviews; the off-target MC4R effect was deliberate enough that it became the basis for bremelanotide.

PubMed: melanotan II melanocortin receptor pharmacology

MT-II use is associated in multiple published case reports with melanoma and with darkening/proliferation of melanocytic nevi (moles).

Several independent human case reports and case-report reviews describe melanoma diagnosed during/after use and mole darkening or new dysplastic nevi; association only, causation not established.

Melanotan-associated melanoma (Br J Dermatol 2011)

Melanotan II nasal spray use has been reported before an oral mucosal malignant melanoma in a 22-year-old woman.

Single case report; association only, with no way to separate drug from other causes.

Int J Oral Maxillofac Surg 2025 (PMID 40210573)

MT-II has been linked in case reports to severe systemic events: priapism requiring intervention, rhabdomyolysis, renal infarction, and posterior reversible encephalopathy syndrome.

Multiple individual human case reports (e.g., a ~39-year-old man with systemic toxicity, rhabdomyolysis and renal dysfunction after a 6 mg internet-sourced dose); rare but serious, documented in peer-reviewed literature.

PubMed: melanotan II injection resulting in systemic toxicity and rhabdomyolysis (Clin Toxicol 2012)

Status

MT-II is not approved for any indication and is illegal to sell for human use; regulators (FDA, MHRA, TGA, EMA) have issued warnings, and FDA sent a warning letter to a US seller (Melanocorp).

Regulatory fact, not a clinical-efficacy claim: FDA warning letter and international agency warnings are documented; grade reflects certainty of the regulatory status, not benefit.

FDA, proposed debarment of Melanocorp owner (docket FDA-2015-N-4169), describing the August 2007 warning letter

Status

A separate MC1R-selective melanocortin peptide (afamelanotide / Scenesse) did complete Phase III and gain FDA approval in 2019, but for erythropoietic protoporphyria, not cosmetic tanning, and it is a different molecule from MT-II.

FDA approval of afamelanotide is established fact; included only to prevent the common conflation, it does NOT transfer evidence to MT-II.

DailyMed. SCENESSE (afamelanotide) label

Risks and the label warnings

Adverse events

Common and well-attested from human use: nausea and facial flushing (frequently in the first hour post-dose), reduced appetite with unintentional weight loss, spontaneous erections/increased libido in men, and disproportionate darkening of moles, freckles, scars, and nails (melanonychia). Severe but rarer events documented in peer-reviewed case reports include priapism requiring intervention, rhabdomyolysis, acute kidney injury / renal infarction, posterior reversible encephalopathy syndrome, and melanoma diagnosed during or after use.

Contraindications

Anyone with personal or family history of melanoma or atypical/dysplastic nevus syndrome, or numerous/changing moles. Cardiovascular disease or uncontrolled hypertension (melanocortin agonism can raise blood pressure). Pregnancy or breastfeeding. Because effects on appetite, mood, and the cardiovascular and renal systems are real, anyone on relevant medications or with renal impairment should treat it as off-limits. No prescriber oversight exists for gray-market product, which compounds every contraindication.

Theoretical concerns

Because MT-II is a potent, non-selective melanocortin agonist, it acts on receptors governing pigmentation, sexual function, appetite, cardiovascular tone, and immune signaling simultaneously, so unintended systemic effects are mechanistically expected, not surprising. The central concern is melanoma: a drug that stimulates melanocyte activity and is known to darken and change existing nevi raises a biologically plausible (though unproven) malignancy worry, which is exactly the signal you cannot afford to be wrong about and which no trial has powered to rule out.

What nobody knows yet

There is no long-term human safety data, no defined safe cumulative dose, and no established melanoma risk quantification. Gray-market product quality is a major unknown: online MT-II varies in purity, actual peptide content, sterility, and contaminants, and nasal-spray formulations add uncertain, uncontrolled dosing. The real-world adverse-event denominator is unknown because most use is unreported, so case reports almost certainly understate frequency.

What else could explain the result

Tanning attribution is muddied by concurrent UV exposure (sun/beds), self-tanner/bronzer use, and seasonality. MT-II's own effect potentiates with UV, so users rarely isolate it. The libido/erection effect is easily conflated with PT-141 (bremelanotide), which is frequently stacked or sold alongside MT-II. Appetite suppression and weight loss are commonly co-attributed to GLP-1 agonists or stimulants users may be running at the same time.

Is the vial what it says?

Cross-checked the foundational human evidence against PubMed (1996 Dorr/Levine/Hruby/Hadley phase-I pilot, PMID 8637402) and confirmed the regulatory status via FDA (Melanocorp warning letter) plus DermNet's clinical overview and the documented FDA/MHRA/TGA/EMA warnings. Severe adverse events (melanoma association, priapism, rhabdomyolysis, renal infarction, PRES, nevi changes) corroborated across multiple independent peer-reviewed case reports rather than a single source. Pharmacokinetics (~33 min plasma half-life vs 48-72 h melanogenesis) and handling cross-checked across multiple sources. Analog context (afamelanotide/Scenesse approved 2019; bremelanotide/Vyleesi) verified to prevent evidence being mis-transferred to MT-II. The 39-year-old, 6 mg case detail was checked against the 2012 Clin Toxicol abstract.

Half-life and storage

Half-life: Short plasma half-life, commonly reported around 33 minutes to roughly 1 hour, but the biological (melanogenic) effect outlasts it substantially, with pigmentation induced for about 48-72 hours per injection, which is why visible tanning accumulates over days while the peptide itself clears within hours.

Once mixed: Supplied as a lyophilized (freeze-dried) powder. Reconstitute with bacteriostatic water, swirl gently rather than shaking (peptides are shear-sensitive). Store the lyophilized vial frozen (around −20 °C / −4 °F or below) and protected from light; once reconstituted, refrigerate at 2-8 °C and use within roughly 1-2 weeks. Do not re-freeze reconstituted solution, ice-crystal formation degrades the peptide. Gray-market sourcing means cold-chain and purity during shipping are unverifiable, an additional handling risk beyond the user's control.

What I noticed, and what people report

What people report

Volume of reports: strong. Large, consistent community + practitioner record.

High volume. MT-II has one of the larger real-world user footprints among gray-market peptides, sold widely online for over 15 years, heavily promoted on social media (including TikTok nasal-spray trends), with abundant forum and before/after reporting plus enough clinical encounters to generate a recurring case-report literature.

Highly consistent on the core effects: users near-universally report that it works as a tanning agent and that nausea, flushing, appetite suppression, mole/freckle darkening, and (in men) libido/erection effects are common. The anecdotal record and the published human/clinical record agree closely here, unusual for this category, which is why both the benefit signal and the side-effect signal are rated strong.

Mixed-to-reasonable. Much online content is affiliate/vendor material selling 'research peptides' and is discounted accordingly, but the central claims (it tans, it causes nausea/erections, moles darken) are independently corroborated by peer-reviewed human studies and case reports, so the load-bearing signal does not rest on vendors. Long-term safety reassurance from forums, by contrast, carries low credibility against the documented severe-event reports.

Users broadly agree it works, reporting a noticeably deeper, faster, longer-lasting tan with far less sun than usual, which is the main reason the compound stays popular despite its illegality (anecdote).
Nausea and flushing in the first hour after injection, plus reduced appetite (sometimes with unintended weight loss), are described as common and dose-related. (Anecdote.)
Men frequently mention spontaneous erections and higher libido as a notable, sometimes inconvenient, side effect, often the second thing they bring up after the tan (anecdote).
Experienced users and clinicians alike caution that moles, freckles, and scars darken disproportionately and new moles can appear, and advise watching pigmented lesions closely because changes 'get lost in the tan', the recurring real-world worry that overlaps with the melanoma case reports (anecdote).

Reports are anecdote, not proof.

Can you tell if it is working?

Trackable

The tan IS the readout, track skin pigmentation objectively with a clinic melanin-index colorimeter (Mexameter/spectrophotometer), using standardized fixed-lighting, fixed-distance before/after photos as the accessible at-home proxy.

Bloodwork

No blood proxy

Nothing on a routine panel confirms this one. Anyone who says otherwise is guessing.

Melanotan-2 acts on melanocortin receptors to produce effects that are entirely local (skin melanocyte pigment synthesis), CNS-behavioral (libido, erections), or subjective (appetite suppression); none of these generates a circulating analyte, so no routine serum test can register the drug's efficacy.

Read this before you spend on labs

Routine bloodwork cannot prove melanotan-2 is working. Its efficacy signals are cosmetic and behavioral, not biochemical: skin darkening, self-reported increased libido and spontaneous erections, and reduced appetite. There is no orderable LabCorp/Quest test for melanin, eumelanin, or a melanocortin/alpha-MSH efficacy response, and melanogenesis is a local melanocyte process with no circulating proxy. The only lab role on MT-2 is safety monitoring (CBC/CMP, CK if rhabdomyolysis is suspected, dermatologic mole surveillance given melanoma case reports), which tracks harm, not effect. For objective proof it is working, use standardized before/after photographs, not a blood draw.

Other ways to track it

OtherDirect readout

Skin melanin index via reflectance colorimetry (Mexameter/spectrophotometer at a dermatology office or medspa); standardized fixed-lighting, fixed-distance before/after photography as the accessible at-home proxy

A working course shows visibly increasing skin pigmentation and a rising melanin index over successive doses, typically after several injections; existing moles and freckles also darken disproportionately (that darkening is a melanoma safety flag, not a bonus). No pigment change means not responding. Photography is only as objective as your lighting and distance discipline; the clinic colorimeter is the rigorous version.

MT-2 is a non-selective melanocortin agonist; MC1R activation on melanocytes drives cAMP-mediated eumelanin synthesis. Increased pigmentation is the direct, objective downstream readout of the drug's primary effect, and it is the one efficacy signal, since nothing on a routine blood or urine panel measures a melanocortin response. Human pigmentation increase from melanocortin-1 agonism is established (its FDA-approved analog afamelanotide used melanin density as a trial endpoint).

Baseline photo (and melanin-index reading if accessible) before the first dose; repeat at regular intervals.

Bottom line

MT-2 is unusual among peptides: its main effect is directly visible, so the tan itself is the objective readout, but the proof is pigmentation (standardized photography or, better, a clinic melanin-index colorimeter), NOT any blood, urine, stool, sleep, glucose, VO2max, or body-composition metric. There is no orderable LabCorp/Quest test for melanin or a melanocortin response. Photography is only as objective as your lighting discipline; melanin-index colorimetry is more rigorous but needs a derm or medspa. MC1R genotyping was dropped as a tracking channel: it is a fixed expectation-setter that cannot confirm or rule out that the drug is working, and potent analogs can override MC1R deficits anyway. The libido/erectile and appetite-suppression effects are real but subjective or side-effects with no validated objective tracker (appetite loss may show on the scale, but that is a side effect, not the therapeutic target). Darkening moles are a safety signal, not success. Human efficacy evidence for tanning is early-stage (Grade C) and safety is flagged (case reports of melanoma, priapism, rhabdomyolysis, renal infarction).

Logging baseline vs retest is the whole game. The Truth Tracker is our free log for bloodwork, DEXA, genetics, and wearable data, bring your own numbers.

How to track it

History

First documented human use: First documented human use was a 1996 University of Arizona open-label pilot phase-I study (Dorr, Levine, Hruby, Hadley and colleagues) in which healthy male volunteers received subcutaneous MT-II and developed measurable tanning within about five low-dose injections; the trial also incidentally documented penile erection, nausea, and flushing. No adequately powered, blinded, controlled efficacy-and-safety trial of MT-II for tanning has ever been completed or submitted for approval, its erectogenic property was instead spun off into a separate drug (bremelanotide).

Heads up: this one was not in the July vote, and its review has no date yet

This was NOT among the seven peptides reviewed at the July 23-24, 2026 PCAC meeting. It sits in a later tranche of five (LL-37, GHK-Cu, Dihexa acetate, Melanotan II and PEG-MGF) that FDA says it will bring to the advisory committee before the end of February 2027. As of November 2, 2026, FDA has not set the date or published the Federal Register notice and docket for that meeting, so nothing about it has been heard or voted. The draft enforcement-discretion policy HHS published on October 30 covers six other peptides in the summaries we read and does not name this one (we could not open its appendix). One thing worth being precise about: 'the status is moving' does not mean 'moving toward legal.' Some of these actions tighten access rather than open it, and they can move in different directions for different forms of the same compound. Check both the date and the direction on anything you read.

Checked November 2, 2026 against FDA's meeting page, the Federal Register and press reports of the HHS policy. Verify the current rule, and the direction, before acting.. FDA, PCAC meeting before end of Feb 2027 (date TBD)

1980s-early 1990sMT-II developed at the University of Arizona as a superpotent, cyclic, non-selective alpha-MSH analog ([Nle4, D-Phe7] backbone) intended as a UV-sparing tanning ('sunless tanning') agent.
1996First documented human use: open-label pilot phase-I trial shows visible tanning within ~5 low-dose subcutaneous injections; erections, nausea, and flushing noted as effects.
Late 1990s-2000sMT-II's erectogenic (MC4R) effect is spun off into bremelanotide (PT-141); MT-II itself is never carried through definitive efficacy/safety trials for tanning.
2007FDA sends a warning letter to a US distributor (Melanocorp) for marketing MT-II as an unapproved drug; the firm keeps selling until 2009 and regulators in the UK, Australia, and EU issue parallel warnings over following years.
2010s-2020sGrowing case-report literature ties unregulated MT-II use to melanoma, dysplastic nevi, priapism, rhabdomyolysis, renal infarction, and encephalopathy; gray-market online and nasal-spray sales surge via social media despite illegality.
2019The related but distinct MC1R-selective peptide afamelanotide (Scenesse) gains FDA approval for erythropoietic protoporphyria, frequently mis-cited as validation of MT-II, which it is not.
2026FDA drops MT-II from its Category 2 list after its nominators withdrew it, which is not permission to compound it; MT-II remains unapproved for tanning or any indication.

All sources

DermNet NZ. Melanotan II (clinical overview)(Dermatology reference: mechanism, unapproved status, short- and long-term side effects, melanoma/nevi and rhabdomyolysis/encephalopathy concerns; states it is not recommended for anyone to use.)
PubMed. Melanotan II phase-I human pilot (Dorr 1996, PMID 8637402)(First documented human use establishing the tanning effect; small open-label pilot, also noted erections/nausea.)
PubMed. Melanotan II injection resulting in systemic toxicity and rhabdomyolysis (Clin Toxicol 2012)(Case report: a multi-mg internet-sourced dose causing rhabdomyolysis and renal dysfunction.)
PubMed. MT-II renal infarction case report (CEN Case Rep 2020)(Peer-reviewed case report of renal infarction.)
PubMed. MT-II posterior reversible encephalopathy syndrome case report (Ann Intern Med 2013)(Peer-reviewed case report of PRES.)
PubMed. MT-II priapism case report (BMJ Case Rep 2019)(Peer-reviewed case report of priapism.)
PubMed. Melanotan-associated melanoma (Br J Dermatol 2011)(Case report of melanoma during melanotan use; association, not proven causation.)
PubMed. Melanoma associated with the use of melanotan-II (Dermatology 2014)(Case report of melanoma during MT-II use; association, not proven causation.)
PubMed. Oral mucosal melanoma after MT-II nasal spray (Int J Oral Maxillofac Surg 2025)(Case report; association only.)
FDA, proposed debarment of Melanocorp owner (docket FDA-2015-N-4169), describing the August 2007 warning letter(FDA warning letter to a US seller; MT-II is unapproved and illegal to market for human use. MHRA, TGA, and EMA have issued parallel warnings.)
DailyMed. SCENESSE (afamelanotide) label(FDA-approved MC1R-selective melanocortin peptide for erythropoietic protoporphyria, a DIFFERENT molecule from MT-II, included to prevent conflation.)
ClinicalTrials.gov, melanotan / melanocortin tanning & vitiligo studies(Registry search for investigational MT-II work; confirms no completed approval-grade tanning trial.)
Dorr RT, Lines R, Levine N, Brooks C, Xiang L, Hruby VJ, Hadley ME. 1996 (PMID 8637402)(dose table)
Wessells H, Fuciarelli K, Hansen J, Hadley ME, Hruby VJ, Dorr R, Levine N. J Urol 1998 (PMID 9679884)(dose table)
Wessells H, Levine N, Hadley ME, Dorr R, Hruby V. Int J Impot Res 2000;12(Suppl 4):S74-S79 (PMID 11035391)(dose table)
Huberman Lab, 'Benefits & Risks of Peptide Therapeutics for Physical & Mental Health', Apr 1, 2024, chapter 01:12:09, about 01:15:10 to 01:17:18(dose table)

Not medical advice. Grades reflect the evidence as of the date above and will change as data arrives. Reports from users are anecdote, not proof. Talk to a licensed clinician before you act on anything here.