What is Melanotan II?
Melanotan II (MT-II) is a synthetic cyclic heptapeptide analogue of alpha-MSH (alpha-melanocyte-stimulating hormone) — a naturally occurring neuropeptide produced in the pituitary gland. MT-II was developed in the 1980s at the University of Arizona as part of research into photo-protection and skin cancer prevention. The rationale was straightforward: if a compound could stimulate melanin production without requiring UV exposure, it could potentially provide a protective tan that reduces DNA damage from sunlight.
What researchers discovered was that MT-II engaged multiple melanocortin receptors simultaneously — with effects that went well beyond pigmentation, making it one of the more broadly studied compounds in its class.
The Melanocortin Receptor System
MT-II is a non-selective melanocortin agonist, meaning it activates multiple receptor subtypes. Understanding which receptor does what helps explain MT-II's diverse research profile:
- MC1R (Melanocortin-1 Receptor) — Located in melanocytes. Activation drives melanin synthesis, producing the characteristic tanning and pigmentation effect. UV exposure is still required to trigger full melanogenesis, but MC1R activation significantly amplifies the response.
- MC3R (Melanocortin-3 Receptor) — Involved in energy regulation and appetite suppression. MC3R activation is linked to reduced food intake and improved energy balance in pre-clinical research.
- MC4R (Melanocortin-4 Receptor) — Found in the hypothalamus and spinal cord. MC4R activation is responsible for MT-II's effects on sexual function — particularly erection and arousal pathways in both male and female research models. PT-141 (Bremelanotide), a related compound, was developed specifically to target MC4R for sexual function research after MT-II trials identified this effect.
- MC5R (Melanocortin-5 Receptor) — Involved in exocrine gland function; less studied in the context of MT-II research.
Tanning and Pigmentation Research
MT-II was the compound that first demonstrated it was possible to stimulate melanogenesis pharmacologically. Research studies showed that MT-II produced dose-dependent increases in skin pigmentation in human subjects, with effects beginning within days and reaching full expression with UV exposure over several weeks. The pigmentation produced is eumelanin-dominant — the same protective brown/black melanin that natural tanning produces — rather than the less photo-protective pheomelanin produced by some other pathways.
One important research finding is the asymmetric darkening of existing moles (nevi) that is frequently observed. This is a well-documented effect in MT-II research and is typically dose-dependent and reversible upon cessation.
Melanotan I (Afamelanotide) is a selective MC1R agonist — it targets pigmentation with minimal activity at MC3R and MC4R. It is licensed as a pharmaceutical (Scenesse) in Europe for a rare light-sensitivity condition. Melanotan II is non-selective and shorter-acting, with broader receptor activity including the MC4R-driven effects on sexual function. Most research interest in MT-II relates to this broader receptor profile.
Sexual Function Research
The discovery of MT-II's effects on sexual function emerged during pigmentation trials when male study subjects reported spontaneous erections as an unexpected finding. Subsequent research confirmed that MC4R activation in the hypothalamus and spinal cord drives erectile response and increased arousal in animal models and human studies. This observation led directly to the development of PT-141 (Bremelanotide), which was designed to retain the sexual function mechanism while reducing pigmentation effects.
MT-II has been studied in both male and female sexual dysfunction research models. Female studies have shown increased sexual motivation and genital response in pre-clinical models, aligning with the broader understanding that the melanocortin system plays a central role in sexual function regulation.
Appetite and Metabolic Research
MC3R and MC4R activation by MT-II produces measurable appetite suppression and alterations in energy balance in pre-clinical research. Studies have demonstrated reduced food intake, increased energy expenditure, and reduced body weight gain in animal models. This metabolic profile has attracted research interest in the context of obesity and metabolic disorders, though MT-II's non-selectivity means the sexual function and pigmentation effects accompany any appetite-related research protocol.
Side Effect Profile in Research
MT-II has a well-characterised side effect profile that is consistently dose-dependent:
- Nausea — the most common reported effect, particularly at higher doses or rapid dose escalation. Typically transient and resolves within 1–2 hours.
- Facial flushing — vasodilatory effect, usually brief.
- Spontaneous erections — in male subjects, via MC4R. Dose-dependent.
- Darkening of moles — the most clinically significant finding to monitor in research protocols. Existing nevi frequently darken during MT-II use.
- Appetite suppression and fatigue — particularly during loading phases.
- Yawning — a reported effect linked to central nervous system melanocortin receptor activity.
All documented side effects in research studies are dose-dependent and typically resolve upon dose reduction or cessation.
Typical Research Protocols
Published research and documented protocol discussions reference two general phases for MT-II use:
- Loading phase — daily subcutaneous administration of 0.25–0.5mg, combined with UV exposure (natural sunlight or tanning bed), until desired pigmentation is established. Duration typically 2–4 weeks depending on skin type and response.
- Maintenance phase — reduced frequency (1–2× per week) at 0.5–1mg, with continued UV exposure as needed. This phase can extend the pigmentation result significantly.
Starting at the low end of the dose range and titrating upward based on individual response is the approach most consistently referenced in research documentation — particularly for minimising nausea during the loading phase.
Where to Buy Melanotan II in South Africa
LA LAB supplies high-purity MT-II (Melanotan II) in South Africa, third-party tested by Janoshik Analytical for identity and purity. All orders are dispatched Monday–Friday with overnight nationwide courier delivery in cold-chain packaging.
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