QUESTIONS / THE RECORD
Melanotan 2 Questions, Answered From the Literature
Direct answers, cited where the claim is quantitative.
What is Melanotan 2?
Melanotan 2 is a synthetic, cyclic, truncated analog of the natural pigment hormone alpha-MSH, designed to be superpotent and durable [7]. In a placebo-controlled pilot Phase I study, subcutaneous Melanotan 2 increased pigmentation in two of three healthy male volunteers after only five low doses, alongside spontaneous erections and mild nausea [1]. It is a non-selective melanocortin agonist with no approved human use.
What is Melanotan 2 used for in research?
In research, Melanotan 2 is used to study the melanocortin system — pigmentation, appetite, energy balance, and erectile signaling — and it serves as a standard pharmacological tool compound for the melanocortin receptors [31]. Its small human studies examined skin pigmentation [1] and erectile function [2]. It has no approved therapeutic use; all human dosing in the literature is study-design data, not a treatment.
What is the difference between Melanotan 1 and Melanotan 2?
Melanotan I is the linear analog, relatively selective for the pigment receptor MC1R; Melanotan 2 is the cyclic, truncated version that reaches all five melanocortin receptors [3]. The breadth is the difference: Melanotan 2 also suppresses appetite and triggers erections. Melanotan I (afamelanotide) is approved for a rare light-sensitivity disorder; Melanotan 2 holds no approval anywhere [3].
Where is Melanotan derived from or made?
Melanotan is entirely synthetic, made by peptide synthesis as a designed copy of the body's own alpha-MSH — a peptide cut from the precursor protein POMC [8]. It is not extracted from any plant or animal. Material sold online is manufactured without oversight, and forensic analyses repeatedly find inaccurate labeling and variable content [14].
What receptors does Melanotan 2 bind?
Melanotan 2 is a non-selective agonist of all five melanocortin receptors, MC1R through MC5R [8]. MC1R governs pigmentation, MC4R (with MC3R) governs appetite and sexual function, MC3R governs energy balance, and MC5R is linked to gland function. Hitting all five at once is why one compound tans, suppresses hunger, and drives erections [8].
What is the molecular weight and structure of Melanotan 2?
Melanotan 2 is a cyclic (lactam-bridged) heptapeptide, sequence Ac-Nle4-cyclo[Asp5-His6-D-Phe7-Arg8-Trp9-Lys10]-NH2, with molecular formula C50H69N15O9 and a molecular weight of about 1024.2 daltons; its CAS number is 121062-08-6 [7]. The lactam bridge closes it into a ring, raising potency and resistance to enzymatic breakdown over linear alpha-MSH [7].
How do you reconstitute Melanotan 2 for research?
This site does not give reconstitution or injection instructions. The literature reports Melanotan 2 as a lyophilized (freeze-dried) powder kept cold and dry, with reconstituted solutions generally refrigerated at about 4 degrees Celsius per general peptide-laboratory practice [7]. Because the online product is unregulated, its actual content and purity cannot be known [14]. Melanotan 2 is not approved for human use.
How does Melanotan 2 work in the body?
Melanotan 2 mimics alpha-MSH and activates the melanocortin receptors [3]. On skin pigment cells it raises cyclic AMP and drives the PKA-CREB-MITF cascade to make dark eumelanin without UV [8]. In the brain, MC4R activation reduces appetite and drives erectile signaling [5][2]. The full path is on the melanotan 2 mechanism of action page.
What is the melanogenesis (MC1R-cAMP-MITF) signaling cascade?
It is the chain that turns a melanocortin signal into pigment: MC1R activation raises cyclic AMP, which activates PKA, which phosphorylates CREB, which drives MITF, the master pigment-cell transcription factor, which upregulates tyrosinase to synthesize melanin [8]. Melanotan 2 starts this cascade directly, shifting output toward dark eumelanin without sunlight [8].
Does Melanotan work without sun exposure?
Yes — that is the point of the mechanism. By activating MC1R directly, Melanotan 2 drives melanin synthesis without UV light. In the pilot Phase I study, two of three volunteers darkened after only five low subcutaneous doses with no required UV exposure [1]. The pigment is made downstream of the receptor signal, not from sun damage.
How long does it take to tan with Melanotan 2?
In the human pilot study, measurable facial and upper-body pigmentation appeared in two of three subjects after only five low doses given over about two weeks [1]. Users commonly report visible darkening within days [27]. Speed varies with the individual and is not well characterized beyond these small data, and no timeline here is a use recommendation.
How long does the tan from Melanotan last? Is it permanent?
The tan is not permanent. Pigmentation persists for weeks after the peptide has cleared because melanin synthesis continues downstream of the signal, but it fades once dosing stops [1]. Users frequently report the color fading slowly and patchily over weeks to months, with moles sometimes staying darker than before [27].
What does Melanotan do for men?
In men, Melanotan 2 darkens skin and produces a well-documented erectile effect: in a controlled crossover study of ten men with psychogenic erectile dysfunction, it produced erections in eight of ten, with mean rigidity duration of 38.0 minutes versus 3.0 minutes on placebo [2]. Spontaneous erections and reduced appetite are also commonly reported [1].
Does Melanotan affect erectile function in the research?
Yes. A double-blind, placebo-controlled crossover study found subcutaneous Melanotan 2 (0.025 mg/kg) produced clinically apparent erections in eight of ten men with psychogenic erectile dysfunction, with greater-than-80% rigidity lasting a mean 38.0 minutes versus 3.0 minutes on placebo [2]. The effect is central and brain-mediated, not vascular [2].
Does Melanotan cause fat loss?
In animals, central Melanotan 2 reduces food intake and body weight: microinjected into the nucleus accumbens it cut food consumption and food-seeking in mice without taste aversion [5], and in obese rats it reduced intake and weight while improving insulin sensitivity [6]. Users commonly report reduced appetite and weight loss [27]. No controlled human weight study exists.
Is Melanotan 2 safe to use?
Its safety is not established, and serious harms are documented. A nephrology review reported renal infarction most likely attributable to Melanotan 2, and prior rhabdomyolysis and renal failure [4]. Priapism, melanoma, eruptive moles, and PRES appear in case reports [17][12][9][20]. With no approval and no quality control on the product [26][14], it should be treated as an unapproved research chemical.
Does Melanotan 2 affect the kidneys?
Case reports link it to serious kidney injury. A nephrology review described renal infarction — sudden loss of blood supply to the kidney — most likely attributable to Melanotan 2, proposing both thrombotic and direct toxic renal mechanisms, and noted prior reports of rhabdomyolysis with renal failure [4][16]. These are single-patient reports, but the signal is serious.
Can Melanotan affect the appearance of moles?
Yes, and this is its most worrying signal. Because it drives pigment cells across the whole skin, case reports document darkening of existing moles, eruptive new moles, dysplastic (atypical) moles, and frank melanoma in melanotan users [9][10][11][12]. Dermoscopy studies show measurable change in moles during use [15]. Any new or changing mole warrants prompt dermatological assessment.
What does the research say about melanotan and erythropoietic protoporphyria (EPP)?
EPP is a rare inherited disorder causing painful skin reactions to brief sun exposure. The linear analog Melanotan I (afamelanotide) — not Melanotan 2 — completed trials and is approved for EPP [3]. That approval and its trial safety data do not extend to Melanotan 2, which is a different, unapproved compound.
Is Melanotan 2 legal, and why do regulators warn against it?
Melanotan 2 is not approved for any use, and selling it for human consumption is unlawful [1]. Regulators including the FDA, TGA, MHRA, and HPRA warn against melanotan tanning products because of documented harms — mole change and melanoma, kidney and muscle injury, priapism — and because online product is unregulated and often mislabeled [26][14].
What is the difference between Melanotan 2 and PT-141 (bremelanotide)?
Both grew from the same melanocortin scaffold, but the spin-off compound was optimized toward MC4R-mediated sexual effects with reduced pigmentation activity, and it holds its own separate approval for a sexual-desire disorder [3]. Melanotan 2 is the broader, non-selective parent with no approval anywhere; the spin-off's approval does not apply to Melanotan 2 [3].
What are typical before-and-after pigmentation results reported in studies?
The controlled data are limited to the pilot Phase I study: subcutaneous Melanotan 2 increased facial, upper-body, and buttock pigmentation in two of three healthy male volunteers after only five low doses, without required UV exposure [1]. Beyond that, pigmentation results come from case reports and forum accounts, which describe rapid darkening but are not controlled evidence [27].