Sexual Health In Vitro Research Only

Melanotan II: UV-Independent Pigmentation & Melanocortin Research

MC1–4R Non-Selective Melanocortin Receptor Agonist

Melanotan II (MT-II) is a synthetic cyclic analogue of alpha-MSH developed at the University of Arizona in the 1980s as a potential sunless tanning agent. As a non-selective melanocortin receptor agonist, it activates MC1R (pigmentation), MC3R/MC4R (sexual arousal, appetite), simultaneously producing effects across multiple biological systems. The unexpected MC4R-mediated erection findings during Arizona tanning trials led directly to the development of PT-141 (Bremelanotide).

For in vitro laboratory research use only. Not for human consumption. All findings described are from preclinical or in vitro models.

MECHANISMS OF ACTION

In vitro and preclinical mechanistic observations

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MC1R Eumelanin Production

Stimulates melanocytes to produce and release eumelanin (dark melanin pigment), darkening skin without UV exposure — confirmed in fair-skinned (Fitzpatrick I–II) human subjects.

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MC4R Sexual Arousal (Central)

MC4R activation in the hypothalamus triggers central sexual arousal pathways — the precursor mechanism that led to PT-141 development as a targeted sexual health compound.

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MC3R/MC4R Appetite Suppression

Reduces food intake and body weight in obese rodent models (ob/ob and db/db mice), confirming the melanocortin system's energy balance role.

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Non-Selective Multi-Receptor Profile

Unlike PT-141 (selective MC3R/MC4R), MT-II activates all MCR subtypes — creating broader biological effects and a higher side effect burden than selective analogues.

KEY RESEARCH DATA

Quantitative findings from published preclinical research

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UV-0

UV Exposure Required

Tanning without sun (Dorr 1996)

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1980s

University of Arizona

Origin of melanocortin research

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MC1–4

Receptors Activated

Non-selective agonist profile

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→PT-141

Led to Derivative

FDA-approved Bremelanotide

Melanocortin Receptor Activation Profile — Melanotan II vs. Alpha-MSH

MC1R (Pigment)

MC2R (ACTH)

MC3R (Appetite)

MC4R (Arousal)

Relative receptor activation (%). Source: Dorr et al. (1996) JAMA; Wessells et al. (1998) Urology. Preclinical / in vitro data.

PRECLINICAL SAFETY PROFILE

Observed tolerability data from in vitro and animal model research

68%

Tolerability

Medium Severity

55%

Nausea Incidence

Medium Severity

35%

Spontaneous Erection (M)

Medium Severity

Safety data reflects preclinical observations only. Human clinical safety profiles may differ substantially. For in vitro laboratory research use only. Not for human consumption.