Melanotan II
Animal-onlyMT-II · Melanotan-2 · Melanotan 2 · Melanotan II
Limited evidence: the strongest curated study is Animal-only; no human-trial data found as of 2026-06-04.
Chemical & identity
- Molecular formula
- C50H69N15O9
- Molecular weight
- 1024.2 g/mol · PubChem
- PubChem CID
- 92432 · PubChem
- SMILES
- CCCC[C@@H](C(=O)N[C@H]1CC(=O)NCCCC[C@H](NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H](NC(=O)[C@@H](NC1=O)CC2=CN=CN2)CC3=CC=CC=C3)CCCN=C(N)N)CC4=CNC5=CC=CC=C54)C(=O)N)NC(=O)C
- InChIKey
- JDKLPDJLXHXHNV-MFVUMRCOSA-N
- Category
- Melanocortin
Chemical/structural fields are auto-pulled and source-linked.
Mechanism (curated)
Synthetic cyclic non-selective melanocortin receptor agonist; activates MC1R (driving melanogenesis/skin tanning) and MC3R/MC4R (affecting sexual function and appetite).
Pharmacology & handling
- Half-life
- Not well characterized in humans.
Research
Yassin Alsabbagh A, Bhujel N, Singh RP · International journal of oral and maxillofacial surgery · 2025 · Case report/series
A case report describes a 22-year-old female who developed oral mucosal malignant melanoma in the anterior maxilla after using Melanotan II nasal spray for tanning purposes. Melanotan II is a synthetic analogue of melanocyte-stimulating hormone and is unlicensed and illegal in the United Kingdom and many other countries. Histological analysis confirmed the diagnosis of mucosal malignant melanoma, and the patient underwent surgical resection followed by immunotherapy. The report includes a literature review on the potential association between Melanotan use and malignant melanoma development and highlights the need for awareness of possible serious side effects.
Gilhooley E, Daly S, McKenna D · Dermatology (Basel, Switzerland) · 2021 · Narrative review
This qualitative study analyzed 623 discussion entries from 205 participants across UK and Ireland online forums (January 2016 to October 2017) regarding melanotan II (MT II), a synthetic α-melanocyte-stimulating hormone analogue used as an unregulated tanning agent. Thematic analysis identified motivations for use (tanned appearance, holidays, fitness competition), misinformation around the unregulated product, dosing regimens, and reported side effects. The authors concluded that clinicians should be aware of risks including pigmented skin lesions, infectious disease transmission, contaminated products, polypharmacy, and concurrent sunbed exposure.
Bonchev A · Life (Basel, Switzerland) · 2026 · Case report/series
This case report describes a patient who self-administered Melanotan II injections over 64 days for tanning purposes and developed oral pigmentation changes. Melanotan II is an unlicensed synthetic peptide that activates melanocortin 1 receptors to stimulate eumelanin production. The patient developed brown pigmentation on attached gingiva and buccal mucosa, which partially resolved after discontinuation but gingival pigmentation persisted at three-month follow-up with reduced intensity. The authors note a lack of published data on the timeline for resolution of oral pigmentation associated with Melanotan II use.
Melanotan II: a possible cause of renal infarction: review of the literature and case report.
AnecdotalPeters B et al. · CEN case reports · 2020 · Case report/series
This case report and literature review describes renal infarction (acute disruption of renal blood flow) potentially associated with Melanotan II, a non-selective melanocortin-receptor agonist. The authors note that Melanotan II is used to increase skin pigmentation and produce sexual effects in humans. Previous reports have documented that Melanotan II can induce rhabdomyolysis and renal failure. The authors propose that renal injury from Melanotan II may involve thrombotic effects and/or direct toxic effects on renal tissue, though the exact mechanism is not established.
McMillan TR et al. · Experimental physiology · 2021 · Animal study
This animal study examined whether melanotan II (MTII), a melanocortin receptor agonist, could rescue impaired thermogenic capacity in PACAP-deficient mice. Female PACAP knockout and wild-type mice received daily peripheral injections of MTII for 3 weeks during cold acclimation. MTII partially restored thermogenic capacity in PACAP-deficient mice as measured by noradrenaline-induced metabolic rate, and corrected deficits in lipid mobilization in response to adrenergic stimulation. The findings suggest that PACAP acts upstream of the melanocortin system to regulate sympathetic nerve activity and adaptive thermogenesis in response to cold.
Jain S et al. · American journal of physiology. Endocrinology and metabolism · 2018 · Animal study
This animal study in mice demonstrates that melanotan II (MTII) causes hypothermia through mast cell activation and histamine H1 receptor signaling, independent of canonical melanocortin receptors. MTII-induced hypothermia was abolished in mast cell-deficient mice but preserved in mice lacking melanocortin receptors 1, 3, 4, or 5, and in MRGPRB2-null mice. MTII activated mast cells both in vitro and in vivo, resulting in elevated plasma histamine levels, and selective H1 receptor antagonism or H1 receptor ablation greatly diminished the hypothermic response. The results suggest mast cell activation should be considered when investigating drug-induced hypothermia mechanisms.
Tomassi S et al. · Journal of medicinal chemistry · 2022 · Other
This study describes the chemical modification of melanotan II (MT-II), a potent but non-selective human melanocortin receptor (hMCR) agonist, by replacing its lactam cyclization with xylene-derived thioether linkers using the Chemical Linkage of Peptide onto Scaffolds (CLIPS) strategy. The newly designed peptides showed binding affinities in the low nanomolar to sub-micromolar range, with one compound (5) demonstrating functional selectivity toward the hMC1R subtype, in contrast to the parent MT-II. Molecular dynamics simulations and cryogenic electron microscopy-based modeling were used to characterize how the cyclization strategy affects peptide conformational behavior and receptor affinity.
Melanotan-II reverses autistic features in a maternal immune activation mouse model of autism.
Animal-onlyMinakova E et al. · PloS one · 2019 · Animal study
Melanotan-II (MT-II), a melanocortin receptor 4 agonist, was tested in a maternal immune activation (MIA) mouse model of autism. Male MIA mice treated with continuous MT-II for seven days showed rescue of impaired social behavior, diminished vocal communication, and increased repetitive behaviors. Normal C57 background mice treated with MT-II showed no significant changes in social metrics but did experience significant weight loss. The study concludes MT-II is effective for improving autism-like behavioral deficits in the adult male MIA mouse model.
Chen AS et al. · Transgenic research · 2000 · Animal study
This study evaluated the role of the melanocortin-4 receptor (MC-4R) in controlling metabolic rate and food intake in mice using the MC-R agonist melanotan II (MT-II). Intraperitoneal administration of MT-II increased metabolic rate in wildtype mice but had no effect in MC-4R knockout mice. MC-4R knockout mice were also insensitive to MT-II's food intake-reducing effects. The authors conclude that MC-4R mediates control of both metabolic rate and food intake in response to MT-II, and that MC-3R plays a limited role in these acute effects.
Ford CL et al. · Neuropharmacology · 2024 · Animal study
In a prairie vole study, melanotan II (MTII), a melanocortin receptor agonist, was administered prior to social interactions between males and females. The study examined MTII's effects on oxytocin-dependent neuronal activation using Fos expression as a marker. In non-social contexts, MTII activated only the hypothalamic paraventricular nucleus; however, during social interactions, MTII selectively increased oxytocin-dependent activation of the nucleus accumbens, a brain region critical for social learning. The authors propose this mechanism may explain MTII's previously observed acceleration of partner preference formation and suggest that melanocortin agonist-induced activation of the endogenous oxytocin system during behavioral therapy could facilitate social learning in contexts such as autism-related social deficits.
Mallory CW, Lopategui DM, Cordon BH · Sexual medicine · 2021 · Case report/series
This case report describes a patient who developed acute ischemic priapism after subcutaneous injection of melanotan II, an injectable melanocortin analog used illicitly for sunless tanning and as a sexual stimulant. The patient initially failed cavernosal aspiration, irrigation, and intracavernous phenylephrine injection, and subsequently underwent operative penoscrotal decompression. The authors note that priapism after melanotan II injection has been reported only twice previously in the literature and suggest that future therapeutic applications and management guidelines should consider priapism as a possible side effect.
Brito MN et al. · Endocrinology · 2007 · Animal study
This animal study (Siberian hamsters) examined how melanotan II (MTII), a synthetic melanocortin 3/4-receptor agonist administered to the brain, affects sympathetic nervous system activity in fat tissues. Central MTII administration increased sympathetic drive (measured by norepinephrine turnover) to certain white adipose tissue depots and brown adipose tissue, elevated circulating free fatty acids and glycerol, and increased brown adipose tissue temperature. The results suggest MTII promotes lipid mobilization through sympathetic innervation of white adipose tissue rather than through circulating hormones, and increases brown adipose tissue thermogenesis via melanocortin-4 receptor activation.
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Regulatory status
- FDA approved
- No
- WADA prohibited
- No
- Compounding status
- Unapproved; sold illicitly as a tanning / sexual-enhancement injection.
- Notes
- Not approved by the FDA for any use; marketed illicitly as a tanning and libido injection. Associated with serious adverse events in case reports (concern over changes in melanocytic lesions/melanoma, priapism, renal infarction). As of 2026-06-04, not listed on the WADA prohibited list.
Legal/regulatory status varies by jurisdiction and changes over time — accurate as of last review (2026-06-04).
Data sources: Curated IDs (PubChem/UniProt/ChEMBL) + Europe PMC + ClinicalTrials.gov (2026-06-04).
Last reviewed 2026-06-04