Melanotan 2

Melanotan II is a synthetic non-selective melanocortin receptor agonist that binds MC1R, MC3R, MC4R and MC5R. As of 2026, it is not listed by name in any SAHPRA schedule under the Medicines and Related Substances Act, yet still falls within the Act's broad "medicine" definition as an unregistered, pharmacologically active peptide — because any substance presented for modifying physiological function requires registration before sale [1][2]. That regulatory gap sits between a decade-old 10 November 2014 CANSA melanoma warning [4] and active vendor pages, with no SAHPRA enforcement notice naming the compound since [3]. It is pharmacologically distinct from Melanotan I (afamelanotide, Scenesse), which the EMA authorised in 2014 solely for erythropoietic protoporphyria [17].

Research use only. Not approved for human therapeutic or cosmetic use in South Africa or any jurisdiction.

Key Takeaways

• Melanotan II is an unregistered, non-selective melanocortin agonist not approved by regulators in Australia, the UK or the US; SAHPRA has not registered it in South Africa
• It differs from Melanotan I (afamelanotide/Scenesse), which is EMA-approved and MC1R-selective; MT-II engages four receptor subtypes simultaneously, producing pigmentation alongside appetite, sexual and autonomic effects
• SAHPRA has not registered MT-II and no Section 21 authorisation for cosmetic use is on public record; sale remains prohibited under the Medicines and Related Substances Act despite the absence of a specific scheduling entry
• Documented adverse events include melanoma, atypical naevi, rhabdomyolysis and priapism; long-term human safety data does not exist because the therapeutic development programme halted in the 1990s–2000s
• Baseline dermatological assessment and follow-up dermoscopy for any changing naevus are the only available safety-monitoring tools for users in South Africa
• JCSG.org supplies Body Pharm research-grade MT-II for qualified researchers; current availability and pricing are shown in the buy box above

What Is Melanotan II? A Plain-Language Definition

Melanotan II (MT-II) is a synthetic cyclic heptapeptide analogue of α-melanocyte-stimulating hormone (α-MSH). It is engineered as a non-selective agonist at MC1R, MC3R, MC4R and MC5R [2][6]. It is a research compound, not an approved medicine in South Africa, the EU, the UK, the US or Australia — no regulatory authority has authorised it for any therapeutic or cosmetic indication [9]. The FDA has explicitly stated it is not a legal ingredient in any approved medicine, supplement or cosmetic [18].

Endogenous α-MSH is a 13-amino-acid peptide cleaved from pro-opiomelanocortin. MT-II shortens that sequence to seven residues and closes a lactam bridge between residues 5 and 10, producing a conformationally constrained ring. Both structural changes were designed to raise binding affinity across the melanocortin receptor family and resist enzymatic degradation that would otherwise clear linear α-MSH within minutes.

Why the structural distinction matters

The cyclisation is why MT-II behaves so differently from native α-MSH. A linear peptide with minutes-long plasma stability cannot reach pigmentary, central nervous system or cardiovascular targets at meaningful concentrations from a subcutaneous dose. A stabilised heptapeptide persists long enough to engage multiple receptor subtypes systemically [6]. That same non-selectivity is why MT-II's pharmacology cannot be cleanly separated from its adverse-event profile, including the melanocytic, neurological and sexual effects documented in case reports [6][7].

Readers comparing MT-II to other research peptides covered on this site can review the GHK-Cu peptide and BPC-157 research overview pages for context on how dermatological and systemic peptides are characterised pharmacologically.

Melanocortin Receptor Pharmacology

Melanotan II is a non-selective agonist at four of the five melanocortin receptor subtypes (MC1R, MC3R, MC4R, MC5R). That lack of selectivity is the central pharmacological reason its effects extend well beyond pigmentation into appetite, sexual function and autonomic signalling [2][9]. The melanocortin family comprises five G-protein-coupled receptors, each with a distinct tissue distribution: MC1R on melanocytes, MC2R on the adrenal cortex (the adrenocorticotropic hormone receptor, not bound meaningfully by MT-II), MC3R and MC4R in the central nervous system, and MC5R in exocrine glands and peripheral tissues.

MC1R: pigmentary signalling

MC1R sits on the melanocyte plasma membrane. When activated, it shifts melanogenesis from phaeomelanin (red-yellow) toward eumelanin (brown-black) via cyclic adenosine monophosphate (cAMP)-mediated upregulation of tyrosinase. Elevated cAMP activates protein kinase A, which phosphorylates CREB and upregulates the master melanocyte transcription factor MITF [9]. This is the receptor responsible for the visible tanning response and the only melanocortin receptor that afamelanotide (Melanotan I, Scenesse) needs to engage to deliver its EMA-approved phototoxicity-prevention effect in erythropoietic protoporphyria [14]. A selective MC1R agonist can, in principle, produce pigmentation without engaging the central or sexual pathways below. MT-II cannot.

MC3R and MC4R: central effects

MC3R is expressed predominantly in the hypothalamus and limbic system. It is implicated in energy homeostasis, feeding behaviour and inflammatory tone through modulation of neuropeptide Y and pro-opiomelanocortin signalling in appetite-regulating circuits [9]. MC4R is expressed in the hypothalamus and along spinal autonomic pathways. Its activation mediates two effects that recur throughout the MT-II case-report literature: appetite suppression and penile erection via spinal pro-erectile circuits [11][12]. MC4R is also the molecular target of bremelanotide (Vyleesi), the FDA-approved melanocortin agonist for hypoactive sexual desire disorder [3].

The practical consequence is that a subcutaneous MT-II dose simultaneously stimulates cutaneous pigmentation (MC1R), modulates appetite and autonomic output (MC3R/MC4R), and drives spinal erectile reflexes (MC4R). The frequently reported cluster of nausea, flushing, spontaneous erections, yawning and reduced food intake is not a side-effect profile in the conventional sense. It is the predictable on-target pharmacology of pan-melanocortin agonism [11][12].

Why selectivity is the key distinction from Melanotan I

Afamelanotide and MT-II share the α-MSH-derived heptapeptide scaffold but differ in receptor selectivity and regulatory standing. Afamelanotide is used for its MC1R activity within a controlled clinical indication [14]. MT-II's binding across MC1R, MC3R, MC4R and MC5R makes any pigmentary benefit inseparable from central and sexual effects. This is the pharmacological basis for regulators in Australia, the UK and the US classifying it as an unapproved medicine unsuitable for cosmetic use [2][4][9]. Readers comparing receptor-targeted peptides may find the GHK-Cu peptide and BPC-157 research overview useful for contrast, as both act through distinct, non-melanocortin mechanisms.

Melanotan II vs Melanotan I: Key Differences

Melanotan I (afamelanotide) and Melanotan II are pharmacologically distinct peptides, not interchangeable forms of the same drug. MT-I is a linear 13-amino-acid α-MSH analogue with high MC1R selectivity. It was approved by the EMA in 2014 as Scenesse for erythropoietic protoporphyria (EPP) because its narrow receptor profile confines effects to cutaneous melanogenesis [20]. MT-II is a cyclic 7-amino-acid analogue that agonises MC1R, MC3R, MC4R and MC5R. It holds no medicines approval in any jurisdiction [9][14].

The structural difference drives the clinical difference. Afamelanotide's linear backbone and receptor selectivity confine its primary action to cutaneous melanogenesis, which is why the EMA indication has remained narrow to EPP photoprotection through successive renewals to 2023 [20]. MT-II's cyclic constraint widens its receptor footprint. The same injection that darkens skin via MC1R also engages hypothalamic MC3R/MC4R (appetite, autonomic tone) and spinal MC4R circuits (erectile reflexes) [11][12]. MT-II cannot be reduced to a "tanning version" of afamelanotide without misrepresenting its pharmacology.

Why the conflation matters in South African content

CANSA's 2014 fact sheet on melanotan products treats the two compounds loosely in places. This has propagated into vendor copy and lay reporting that uses "Melanotan" as a single label [6]. In a regulatory frame this is a legally significant error: afamelanotide is a scheduled, EMA-authorised orphan medicine, while MT-II is an unapproved substance flagged by the TGA (Therapeutic Goods Administration), MHRA (Medicines and Healthcare products Regulatory Agency) and DermNet as unlicensed for any indication [2][7][9]. Readers comparing peptide classes can contrast this with mechanistically unrelated compounds such as GHK-Cu or BPC-157, which act outside the melanocortin system entirely.

Side-by-side comparison

Attribute	Melanotan I (afamelanotide)	Melanotan II
Structure	Linear 13-amino-acid α-MSH analogue	Cyclic 7-amino-acid α-MSH analogue
Receptor selectivity	High MC1R selectivity [20]	Pan-agonist: MC1R, MC3R, MC4R, MC5R [11][12]
Approved indication	EPP photoprotection (EMA, 2014; unchanged through 2023) [20]	None, anywhere [9][14]
EMA status	Authorised as Scenesse, orphan designation [20]	Not authorised [9]
FDA status	Approved 2019 for EPP [14]	Never reviewed; not a legal ingredient in any medicine, supplement or cosmetic [15]
SAHPRA status	Listed in Schedule 4 in the 2022 consolidated schedules [1]	Not listed by name in any schedule; falls under the Act's general "medicine" definition [1][2]
Primary research use	Phototoxicity prevention, vitiligo and polymorphous light eruption (PLE) exploratory trials [21]	Receptor pharmacology, appetite and erectile-circuit studies [11][12]
Typical adverse profile	Nausea, transient hyperpigmentation, injection-site reactions [20]	Nausea, flushing, priapism, mole darkening, rhabdomyolysis, melanoma case reports [11][12]

The practical takeaway for any South African reader evaluating sources: if a page uses "Melanotan" without specifying I or II, it is not a reliable starting point for either pharmacological or regulatory questions.

Melanogenesis: How MT-II Stimulates Skin Pigmentation

MT-II produces a tan by hijacking the same intracellular cascade that ultraviolet radiation triggers — starting the chain at the receptor rather than at DNA damage. The peptide binds MC1R on epidermal melanocytes, activating a Gs-protein-coupled cascade that drives synthesis of eumelanin, the brown-black pigment responsible for visible darkening [9].

The molecular sequence runs as follows. MC1R activation stimulates adenylyl cyclase, raising intracellular cAMP. Elevated cAMP activates protein kinase A, which phosphorylates CREB and upregulates microphthalmia-associated transcription factor (MITF). MITF directly transcribes the genes encoding tyrosinase, TYRP1 and DCT. These three enzymes convert tyrosine into eumelanin within melanosomes [9][10]. Mature melanosomes are then transferred along dendritic processes to surrounding keratinocytes, where they cap the nucleus and produce the visible tan.

Eumelanin versus phaeomelanin

Human skin synthesises two chemically distinct pigments. Eumelanin is a brown-to-black polymer that absorbs broadband ultraviolet (UV) radiation and scavenges reactive oxygen species, providing photoprotection [9]. Phaeomelanin is a sulphur-containing red-to-yellow pigment that is far less photoprotective and can generate reactive oxygen species under UV exposure. The ratio between them is largely set by MC1R signalling tone: strong MC1R activation favours eumelanin; weak or loss-of-function MC1R signalling shifts synthesis toward phaeomelanin [9][10].

This is why MT-II produces a darker, more uniform pigmentation than equivalent UV exposure in lighter phenotypes. By driving MC1R activity well above physiological baseline, the peptide pushes the eumelanin:phaeomelanin ratio toward eumelanin even in individuals whose MC1R variants normally bias them toward phaeomelanin [10]. Fitzpatrick skin types I and II, common among South Africans of European descent, show the most pronounced visible change because their baseline eumelanin content is lowest and the relative increase is therefore largest.

Two consequences follow for anyone interpreting the research literature. First, the tan is a pharmacodynamic readout of MC1R engagement, not evidence of safety or selectivity, because the same molecule simultaneously activates MC3R, MC4R and MC5R elsewhere in the body. Second, the pigmentary response is mechanistically distinct from the trophic and repair-oriented pathways studied with peptides such as GHK-Cu or BPC-157, which do not engage melanocortin receptors at all.

Research Applications Beyond Pigmentation

Melanotan II is studied as a non-selective melanocortin agonist in three research areas beyond pigmentation: sexual function, energy balance, and central nervous system signalling. None of these have produced an approved therapeutic indication for MT-II itself in any jurisdiction as of 2026 [9][10].

Sexual function and the bremelanotide lineage

MT-II is the parent compound from which bremelanotide (PT-141) was derived. Early MT-II trials in the 1990s recorded spontaneous erections as a side effect, which prompted structural modification to produce a metabolite-stable analogue optimised for MC4R-mediated sexual response rather than MC1R-mediated pigmentation [8]. Bremelanotide received FDA approval in June 2019 as Vyleesi for hypoactive sexual desire disorder in premenopausal women because it showed efficacy in phase 3 trials without the pan-melanocortin effects of MT-II [8]. That approval applies strictly to bremelanotide. MT-II remains unapproved by the FDA for any indication, and the agency does not consider it a legal ingredient in any medicine, supplement or cosmetic [9].

Appetite suppression and MC4R-driven energy balance

Central MC4R agonism reduces food intake and increases energy expenditure in rodent models, which is why MC4R has become a target for obesity and metabolic disease programmes [10]. Pipeline reviews through 2021–2025 list several investigational MC4R-selective agonists in development, but none has reached FDA approval beyond afamelanotide and bremelanotide [10]. MT-II's non-selectivity across MC1R, MC3R, MC4R and MC5R makes it useful as a pharmacological probe in animal feeding studies but unsuitable as a clinical anti-obesity candidate. The same dose that suppresses appetite also drives pigmentation, cardiovascular and sexual effects.

Behavioural neuroscience and neuroprotection

The central melanocortin system modulates arousal, social behaviour, inflammation and stress responses, and MT-II is frequently used as a research tool to probe these circuits [18]. UNSW's 2023 review notes that the same central activity that makes MT-II valuable in neuroscience also explains the yawning, nausea and altered arousal reported in human case series [3][18]. This is mechanistically distinct from the tissue-repair pathways examined with peptides such as GHK-Cu or the cytoprotective work documented for BPC-157, neither of which engages melanocortin receptors.

SAHPRA Regulatory Status in South Africa (2026)

Melanotan II is not a registered medicine in South Africa as of 2026. It does not appear by name in any schedule (0–8) under the Medicines and Related Substances Act 101 of 1965. It may not lawfully be sold, imported or distributed as a medicine without a Section 21 authorisation from SAHPRA [1][2]. Readers should verify the current status directly against SAHPRA's online register before relying on this summary.

SAHPRA is the competent authority established under the Act, responsible for registering medicines, scheduling substances, and authorising access to unregistered products. Afamelanotide (Scenesse) is listed in the 2022 consolidated schedules in Schedule 4, reflecting its EMA orphan authorisation for erythropoietic protoporphyria [1][14]. MT-II has no scheduling entry, no registration dossier on the public register, and no marketing authorisation.

The "unscheduled ≠ legal" point

A common misreading is that an unscheduled substance is free to trade. The Act's logic runs the other way: any substance meeting the statutory definition of a "medicine" — anything presented or used for diagnosis, treatment or modification of a physiological function — requires registration before sale [1]. A synthetic melanocortin agonist marketed for tanning meets that definition on its face. Absence from the schedules does not confer legality. It means SAHPRA has not yet assigned a specific scheduling status, while the underlying prohibition on selling unregistered medicines still applies [1][2].

Section 21 and the documented gap

Section 21 of the Act allows clinicians to apply for authorised access to unregistered medicines for a named patient with a specific clinical indication [1]. There is no publicly documented Section 21 authorisation for MT-II for cosmetic tanning. SAHPRA's available Section 21 reporting from 2020–2024 focuses on oncology, biologics and rare-disease products [11]. Cosmetic pigmentation is not a recognised clinical indication that would plausibly support such an application.

Enforcement and the CANSA warning

SAHPRA has not issued a named public alert specifically targeting Melanotan II vendors after CANSA's 10 November 2014 warning. That warning flagged melanoma and atypical naevus risks but is advocacy communication rather than a regulatory instrument [3][4]. Australia's TGA, as summarised by UNSW in 2023, classifies MT-II as an unapproved medicine that is illegal to advertise or supply [2][5]. Local enforcement capacity against online vendors remains limited, which is why MT-II listings persist alongside other research peptides such as GHK-Cu and BPC-157 despite the statutory position.

Body Pharm MT-II: Sourcing Notes

Research peptide quality varies between suppliers. Body Pharm MT-II is supplied through JCSG.org to research-grade standards, with South African pricing displayed in the buy box above.

See the full range of Body Pharm peptides for South African researchers: browse all peptides.

Known Side Effects and Safety Signals

Documented adverse effects of Melanotan II span dermatological, neurological, cardiovascular and urological systems. Nausea, facial flushing, spontaneous yawning, fatigue, MC4R-mediated spontaneous erections in males, and darkening of existing naevi are the most consistently reported in case-report literature [5][7][8]. Severe events — including melanoma, atypical melanocytic proliferation, rhabdomyolysis, priapism and encephalopathy — have been described in peer-reviewed case reports through 2023 [8][9].

The naevi signal is the one South African readers should weigh most carefully. CANSA's 2014 communication, co-signed by local melanoma experts, flagged darkening and morphological change in existing moles as a potential precursor signal for melanoma in users of melanotan products. Melanocortin agonism can stimulate proliferation in dormant melanocytic lesions [2]. Causality has not been established in a controlled study, but the 2023 UNSW/TGA review and DermNet's 2023 clinical summary both list melanoma and atypical naevi among the recurrent dermatological findings in published cases [5][7][8].

Quantitative incidence data does not exist. No registry-based pharmacovigilance cohort for Melanotan II has been published in the 2020–2026 window. The evidence base remains case reports and small series rather than systematic spontaneous-reporting database analyses [7][9]. Long-term human safety data is absent because the therapeutic development programme was halted in the 1990s–2000s and no approved clinical trial has since completed [6]. Pre-2020 safety summaries may be superseded by individual 2020–2024 case reports without any reconciling meta-analysis.

Anyone in South Africa weighing use should obtain a baseline full-body skin examination from a dermatologist, disclose intended or actual peptide use to their GP, and arrange follow-up dermoscopy for any naevus that changes in size, colour or border. Early detection of morphological change is the only available safety monitoring tool. Readers researching adjacent dermatological peptides may consult the GHK-Cu peptide overview for receptor and mechanism context that sits outside the melanocortin pathway.

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