⚠ Unapproved drug · high-risk page · read first Melanotan II is not approved by the FDA, EMA, MHRA, or TGA for any indication — not for tanning, not for erectile dysfunction, not for any cosmetic or medical use. The FDA has repeatedly classified marketed melanotan products as unapproved new drugs and issued public warnings citing serious adverse events. Products sold online are unregulated: independent purity analysis found a minority of online samples met their claimed purity, with bacterial endotoxin and unidentified peptide contaminants present in some. Every dose figure on this page is a historical-trial exposure anchor or research-modeling construct, not a recommendation. MT-II does not replace sun protection and does not make UV exposure safe.

Class 09 · Melanocortin & pigmentation · Cyclic α-MSH analog · Nonselective MC-receptor agonist

Melanotan IIMT-II · the melanocortin "tanning peptide" · pigmentation & sexual-function signal

A lab-made cyclic peptide modeled on your body's own α-MSH hormone. It switches on the receptors that tell skin cells to make more pigment — so skin darkens — and also acts on brain circuits that influence sexual arousal and appetite. It was developed in the 1980s as a "sunless tan" candidate but was never approved. Real-world use is unregulated and linked to nausea, flushing, darkening moles, prolonged erections, and — because most product is sold illegally online — uncertain purity. Health agencies worldwide advise against it.

A synthetic cyclic lactam heptapeptide analog of α-melanocyte-stimulating hormone (α-MSH), acting as a nonselective agonist at MC1R, MC3R, MC4R, and MC5R. Dorr 1996 (Life Sci) — pilot Phase I in 3 volunteers demonstrated visible tanning after five low SC doses; recommended single dose for future study 0.025 mg/kg/day. Wessells 1998 (J Urol) — 0.025 mg/kg SC initiated erections in 8/10 men with psychogenic ED. Clinical development of MT-II itself was abandoned; the molecule instead seeded two approved derivatives — afamelanotide and bremelanotide. Modern clinician framing is dermatologic-risk screening, adverse-event recognition, and regulatory caution; no validated dosing protocol exists.

Ac-Nle⁴-cyclo[Asp⁵-His⁶-D-Phe⁷-Arg⁸-Trp⁹-Lys¹⁰]-NH₂ (C₅₀H₆₉N₁₅O₉, MW 1024.18 Da, CAS 121062-08-6, PubChem CID 92432) — a lactam-bridged cyclization of the α-MSH⁴⁻¹⁰ message sequence with the D-Phe⁷ substitution and Nle⁴ that confer superpotent, protease-resistant melanocortin activity. Nonselective melanocortin agonism (MC1R → melanogenesis via Gs/cAMP/PKA/MITF; MC3R/MC4R → central sexual-arousal and energy-balance circuits; MC5R → exocrine/peripheral). Vemulapalli 2001 (Neuroscience): central MC-receptor activation by MT-II produces penile erection in rats independent of peripheral stimulation. Human PK is poorly characterized in accessible validated literature; secondary reports suggest short plasma persistence but MT-II-specific human half-life, Cmax, and clearance are insufficient for precise modeling.

0.025 mg/kg Historical human exposure anchor · Dorr/Wessells (≈1.75 mg @ 70 kg)

4 receptors Nonselective · MC1R / MC3R / MC4R / MC5R

0 approvals Not FDA / EMA / TGA approved · any indication

7 AA · cyclic Lactam heptapeptide · 1024 Da

Status

Unapproved · unregulated · research chemical

Open reconstitution calculator →

Routes (literature)

SC (only trial route) · others unsupported

Originator

Univ. of Arizona · Hadley / Hruby / Dorr · 1980s

WADA status

Unapproved-substance anti-doping risk (verify)

Molecule identity

C₅₀H₆₉N₁₅O₉

Ac-Nle⁴-cyclo[Asp⁵-His⁶-D-Phe⁷-Arg⁸-Trp⁹-Lys¹⁰]-NH₂ · lactam-bridged heptapeptide · synthetic SPPS

ClassSynthetic melanocortin peptide · nonselective MC-receptor agonist

SequenceAc-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH₂

Molecular weight1024.18 Da · C₅₀H₆₉N₁₅O₉ (free base)

Primary targetsMC1R · MC3R · MC4R · MC5R (nonselective)

Downstream effectorscAMP/PKA · MITF/tyrosinase · central hypothalamic circuits

PubChem CID92432 · UNII UPF5CJ93X7 · ChEMBL430239

RoutesSC (trials) · nasal / oral / topical (unsupported market)

SolubilityWater-soluble (~5 mg/mL) · BAC water reconstitution

StorageLyophilized −20 °C · reconst. 2–8 °C, protect from light

Human exposure anchor0.025 mg/kg/day (Dorr/Wessells trials)

Human PKNot well characterized · short plasma persistence (reported)

Key substitutionsNle⁴ · D-Phe⁷ · Asp⁵–Lys¹⁰ lactam (superpotent, stable)

Approved relativesAfamelanotide (Scenesse) · Bremelanotide (Vyleesi)

OriginUniv. of Arizona melanocortin program · 1980s

01 · At a glance

Key facts & headline data.

The defining numbers and claims for Melanotan II — a peptide with genuine human pharmacodynamic signals (pigmentation, erection) drawn from small, decades-old trials, set against an unapproved regulatory status, a meaningful adverse-event record, and an unregulated supply chain. Read every "dose" here as historical-trial exposure or research-model construct, never as a protocol.

🧬

What it is

Cyclic α-MSH analog

A synthetic cyclic lactam heptapeptide (C₅₀H₆₉N₁₅O₉, MW 1024.18, CAS 121062-08-6) that acts as a nonselective agonist at melanocortin receptors MC1R, MC3R, MC4R, and MC5R. Developed at the University of Arizona as a "superpotent" α-MSH analog for sunless tanning research.

🌞

Human tanning signal

Demonstrated

Dorr 1996 (Life Sci, PMID 8637402): 3 volunteers given five low SC doses every other day showed increased facial / upper-body / buttock pigmentation by quantitative reflectance; recommended future single dose 0.025 mg/kg/day. Small but a genuine human pharmacodynamic effect.

💊

Erectile-response signal

8/10 → 17/20 men

Wessells 1998 (J Urol): 0.025 mg/kg SC initiated erections in 8/10 men with psychogenic ED. Wessells 2000 (Urology): in organic-risk ED, MT-II produced subjectively reported erections in 12 of 19 injections vs 1 of 21 placebo; mean tip-rigidity >80% lasted ~45 min.

⚠️

Documented harms

Priapism · lesions

Acute ischemic priapism after SC MT-II is documented in multiple case reports, some requiring surgical decompression. Darkening / changing moles and case reports of melanoma temporally associated with MT-II (confounded by UV / sunbed use) are the central dermatologic concern.

🧪

Supply-chain risk

Purity uncertain

Independent analyses of online melanotan products found only a minority met claimed purity, with bacterial endotoxin and unidentified peptide contaminants in some samples. Nasal sprays, drops, and tablets carry highly variable, unverified content.

📋

Regulatory status (May 2026)

Unapproved

Not FDA-approved for any indication; the FDA has classed marketed melanotan products as unapproved new drugs. Australia's TGA states supplying melanotan tanning products without a prescription is illegal. Two related molecules — afamelanotide and bremelanotide — are approved; MT-II itself is not.

02 · Mechanism of action

How a melanocortin agonist works.

Melanotan II copies a natural hormone called α-MSH and turns on a family of switches called melanocortin receptors. The skin switch (MC1R) tells pigment cells to make more melanin, so skin darkens. Brain switches (MC3R / MC4R) sit on circuits that control sexual arousal and appetite — which is why MT-II can trigger erections and reduce hunger. Because it hits several switches at once and isn't selective, its effects spill over into flushing, nausea, yawning, and changes in moles — you can't get just the tan.

A nonselective melanocortin agonist with effects spanning at least five mechanistic arms. MC1R agonism on melanocytes (Gs → cAMP/PKA → MITF/tyrosinase) drives eumelanin synthesis and visible pigmentation. Central MC3R/MC4R signaling produces erection and increased sexual desire — the basis of the human ED trials and the derivative bremelanotide. MC4R energy-balance circuits suppress appetite. Autonomic / sympathetic activation underlies flushing, nausea, yawning, and rare serious vascular events. Melanocyte stimulation also explains nevus darkening and the dermatologic-surveillance concern. The nonselectivity is the defining limitation: pigmentary, sexual, autonomic, and lesion effects cannot be isolated.

MT-II is a cyclic, protease-resistant α-MSH⁴⁻¹⁰ message-sequence analog whose Nle⁴ and D-Phe⁷ substitutions and Asp⁵–Lys¹⁰ lactam bridge confer superpotent, prolonged, broadly nonselective melanocortin-receptor binding. The melanocortin family (MC1R–MC5R) are Gs-coupled GPCRs governing pigmentation (MC1R), adrenal steroidogenesis (MC2R), central energy balance and sexual function (MC3R/MC4R), and exocrine/peripheral functions (MC5R). Vemulapalli 2001 (Neuroscience, PMID 11591452): central MC-receptor activation by MT-II elicits penile erection in rats, localizing the erectogenic effect to hypothalamic/spinal melanocortin circuitry rather than peripheral vascular action. Hadley 2005 (Peptides): MT-II human work was foundational to recognizing melanocortins as regulators of sexual function, directly seeding the bremelanotide (PT-141) program. Human MT-II PK is insufficiently characterized for confident pathway-kinetics modeling.

🎨

MC1R · melanogenesis / eumelanin pathway

MT-II activates MC1R on melanocytes, increasing melanogenic signaling and eumelanin synthesis — the mechanism behind visible skin darkening. Dorr 1996 demonstrated measurable increases in facial, upper-body, and buttock pigmentation in humans after only five low SC doses, by quantitative reflectance and visual perception. This does not make MT-II a safe substitute for sun protection.

Clinical significance: Pigmentation is the effect users seek, but it is inseparable from systemic melanocortin activity and from melanocyte stimulation that raises dermatologic-surveillance concerns. Pigment changes can outlast plasma drug exposure; mole darkening and new pigmented lesions are documented. Counseling must stress that increased melanin from MT-II is not equivalent to photoprotection and may coexist with continued UV-driven carcinogenic risk.

Molecular detail: MC1R is a Gs-coupled GPCR; agonism raises intracellular cAMP, activates PKA, and upregulates the MITF transcriptional program governing tyrosinase, TYRP1, and DCT — shifting melanocytes toward eumelanin (the photoprotective brown/black pigment) over pheomelanin. Receptor-pharmacology reviews establish MC1R as the dominant pigmentary melanocortin receptor; MT-II's high potency and nonselectivity drive robust but unisolated activation.

🧠

MC3R / MC4R · central sexual arousal & erection

Central melanocortin signaling through MC3R/MC4R drives sexual arousal and erection independent of peripheral stimulation. Wessells 1998: 0.025 mg/kg SC initiated erections in 8/10 men with psychogenic ED. Wessells 2000: in organic-risk ED, erections occurred in 12/19 MT-II injections vs 1/21 placebo, with increased self-reported desire.

Clinical significance: This is a real, double-blind, placebo-controlled human signal — but it came with frequent nausea and yawning, and MT-II's development was abandoned in favor of the more selective derivative bremelanotide (PT-141, approved for HSDD in premenopausal women). The same circuitry that produces a therapeutic erection can produce priapism at the tail of the dose-response, which is the dominant acute danger of recreational use.

Molecular detail: Vemulapalli 2001 localized the erectogenic effect to central MC receptors in rats; hypothalamic (paraventricular nucleus) and spinal melanocortin circuits integrate with autonomic outflow governing erectile physiology. Hadley 2005 framed these human MT-II findings as the discovery that a melanocortin regulates sexual function — the conceptual basis for the bremelanotide program. MC4R is the principal mediator; MC3R contribution is supportive and less defined.

🍽️

MC4R · appetite / satiety signaling

MT-II can reduce appetite, consistent with MC4R's established role in hypothalamic energy balance. Decreased appetite was reported among the human-study side-effect profile, and MC4R agonism is a validated anorexigenic axis (the basis of the approved MC4R agonist setmelanotide in rare genetic obesity).

Clinical significance: Appetite suppression is a side effect, not a validated indication for MT-II. Because the drug is nonselective, weight or appetite effects cannot be cleanly separated from pigmentary, sexual, and autonomic actions, and there is no safety basis for using MT-II as a weight-management tool.

Molecular detail: MC4R signaling in hypothalamic (arcuate → PVN) circuits is a core regulator of feeding and energy expenditure; agonists reduce food intake and increase energy use. MT-II's broad receptor engagement means its energy-balance effects are entangled with autonomic and central arousal effects rather than being an isolated metabolic signal.

💢

Autonomic / sympathetic activation

A substantial share of MT-II's adverse effects appear to stem from central and autonomic activation: nausea, yawning/stretching, flushing, dizziness, and fatigue. A characteristic stretching–yawning complex correlated with the onset of spontaneous erections in the Dorr pilot study; nausea was reported at most dose levels.

Clinical significance: Nausea and flushing are the most common tolerability-limiting effects and frequently drive dose reduction or discontinuation. Rare but serious systemic events — sympathomimetic toxicity with rhabdomyolysis and renal dysfunction — have been reported, particularly with high or co-ingested-substance exposure. These are reasons the "more is better" pattern of recreational use is dangerous.

Molecular detail: Central melanocortin receptor activation modulates autonomic tone and can engage sympathetic outflow; the yawning-stretching-erection syndrome is a recognized melanocortin behavioral signature in animals and humans. A case of renal infarction has been attributed to MT-II, consistent with a vasoactive / pro-thrombotic mechanism, though causality in single cases is uncertain.

🔬

Nevus / pigmented-lesion change

Melanocyte stimulation can darken existing moles and is associated with new or changing pigmented lesions. Sivyer 2013 documented dermoscopic changes in melanocytic lesions induced by melanotan; Hjuler 2014 (JAAD) reported melanoma associated with MT-II use. Whether MT-II directly promotes malignancy is unproven, but lesion change creates real surveillance difficulty.

Clinical significance: This is the single most important dermatologic reason to avoid MT-II, especially in anyone with a personal or family history of melanoma, dysplastic nevi, or many atypical moles. Pigment changes can mask or mimic early melanoma features, complicating the central tool of skin-cancer prevention — surveillance of changing lesions. Any new, changing, or irregular pigmented lesion warrants prompt dermatologic evaluation.

Molecular detail: MC1R-driven melanogenic upregulation increases melanocyte pigment programs broadly; dermatology reviews emphasize the difficulty of separating MT-II effects from concurrent UV / sunbed exposure and baseline melanoma risk. The mechanistic plausibility of melanocyte stimulation plus the confounded human reports yields an unresolved but cautionary cancer-risk signal.

⚗️

Peripheral / MC5R & inflammatory signaling

Melanocortin receptors extend well beyond skin; MC5R and broader melanocortin signaling influence exocrine (e.g. sebaceous) function and immune/inflammatory pathways. The MC1R–MC5R family spans pigmentation, adrenal steroidogenesis, energy balance, exocrine function, and immune modulation, so MT-II should never be regarded as a skin-only agent.

Clinical significance: The breadth of receptor distribution is why systemic effects of a nonselective agonist are hard to predict and to attribute. It also frames why selective successors (afamelanotide via MC1R; bremelanotide via MC4R; setmelanotide via MC4R) were pursued — narrowing the receptor target reduces the off-target burden that makes MT-II problematic.

Molecular detail: MC5R contributes to exocrine-gland regulation; melanocortin signaling participates in anti-inflammatory and immunomodulatory pathways studied for endogenous α-MSH analogs. MT-II's nonselectivity precludes clean assignment of any single peripheral pathway, and no validated human therapeutic exploitation of these arms exists for MT-II itself.

L3 · Downstream pathway

SC exposure → MT-II → Melanocortin Receptors → Central & Peripheral Outputs → Phenotype

💉

SC exposure
≈0.025 mg/kg anchor

→

⚗️

MT-II
(cyclic heptapeptide)

→

🎯

MC1–5R
activation

→

🔁

cAMP/PKA +
central signaling

→

⚙️

Melanin · erection ·
appetite · autonomic

→

🧴

Pigmentation +
systemic effects

→

⚠️

Risk tail:
priapism · lesions

03 · Historical exposure models & reconstitution math

Historical exposure architecture — not recommended protocols.

Melanotan II has no approved dosing protocol for tanning, erectile dysfunction, vitiligo, or any other indication. The only defensible numerical anchors are historical trial exposures (the 0.025 mg/kg/day figure from the Dorr and Wessells studies) and educational reconstitution math — never clinical recommendations. This section is renamed accordingly. It is structured to the same engine skeleton as every other Atlas page — route panels, global dose bands, weight-band interpolation, titration/hard-stop logic, biomarker scaffold, visual exposure model, and reconstitution calculator — but for MT-II the dosing architecture is deliberately framed as historical-exposure modeling, with unsupported routes disabled to warning-only cards and dermatologic hard-stops elevated above the calculator. FDA and other regulators warn against unapproved melanotan products, and informal nasal/oral/topical products raise dose-accuracy, sterility, and mislabeling risks.

⚠ No approved dose exists MT-II is not FDA-approved for any indication; marketed melanotan products have been classified as unapproved new drugs. Australia's TGA states supplying melanotan tanning products without a prescription is illegal. The figures below are historical-trial exposures and reconstitution arithmetic for educational reconstruction only. They are not a recommendation to dose, and the common online "low-dose loading" pattern is not a validated medical protocol.

🛑 Dermatologic hard-stop — read before any exposure model A new, changing, darkening, asymmetric, or irregular pigmented lesion in anyone using or considering MT-II is a hard stop and requires prompt dermatology evaluation, not dose adjustment. Do not model any exposure in the presence of personal or family history of melanoma, dysplastic nevus syndrome, or many atypical moles. MT-II can darken existing moles and is associated with lesion change that complicates melanoma surveillance. MT-II is not sunscreen and does not make UV exposure or tanning-bed use safe.

PK note · why precise dosing is impossible here Human MT-II pharmacokinetics are not well characterized in accessible validated literature — MT-II-specific half-life, Cmax, Tmax, bioavailability, and clearance values sufficient for precise dose modeling are not established. Pigment effects may outlast plasma exposure, so dermatologic monitoring cannot be tied to drug half-life. The historical trials dosed by body weight (0.025 mg/kg) every other day or per-event; informal practice instead uses fixed microgram amounts. Both are shown below as exposure references, not endorsements.

Status

Subcutaneous injection is the only route with direct early human trial evidence. Dorr 1996 dosed 3 volunteers starting at 0.01 mg/kg, escalating by 0.005 mg/kg increments to 0.025–0.03 mg/kg, five doses on alternating days over 2 weeks; visible tanning resulted. There is no approved or validated protocol — this is a historical-exposure reconstruction.

Historical exposure anchor

0.025 mg/kg/day = the dose recommended for future Phase I study in Dorr 1996. For a 70 kg adult this is ≈1,750 µg. This is an anchor for math normalization, not a recommended dose.

"Starting" framing

No clinical starting dose exists. For modeling, the lowest historical entry was 0.01 mg/kg (≈700 µg @ 70 kg). Informal practice instead uses fixed micro-doses (often 100–250 µg) labeled "loading," which is not a validated medical protocol and should be treated as D / unvalidated.

Escalation / titration

No validated escalation protocol. The historical study escalated cautiously by 0.005 mg/kg; the 0.03 mg/kg level produced Grade II somnolence and fatigue in one of two subjects. Do not present any escalation as standard care.

Exposure ladder (model labels)

micro-exposure → historical trial anchor (0.025 mg/kg) → above-anchor (avoid / not modeled). The engine should expose only these descriptive bands, never a consumer "build to maximum tan" ladder.

Maintenance / cycle / washout

No approved maintenance or cycle length. Pigment effects may persist beyond plasma exposure; dermatologic monitoring must continue independent of drug half-life. There is no evidence base for any "maintenance" schedule.

Reconstitution & injection

Typical 10 mg vial + 2 mL bacteriostatic water → 5,000 µg/mL = 50 µg/unit (U-100). A 250 µg model dose = 5 units (0.05 mL); a 500 µg dose = 10 units. 29–31 G insulin syringe, SC, rotate sites; roll — don't shake; refrigerate 2–8 °C, protect from light, avoid freeze-thaw. Use the calculator below for any vial/dose combination — but verify product source, purity, sterility, and endotoxin first.

Monitoring overlay

Nausea, flushing, yawning, appetite suppression, blood pressure / heart rate symptoms, erection duration, and — most importantly — full-body mole / lesion surveillance with photo logging. Any changing lesion is a hard stop (see above).

Contraindication overlay

Avoid in personal/family melanoma history, dysplastic nevi, unexplained changing lesions, pregnancy/breastfeeding, cardiovascular instability, priapism risk (sickle cell), and combined unsupervised UV / tanning-bed use.

Translational caveat

The historical trials are small (n = 3 tanning; n = 10–20 ED), decades old, and not powered for long-term safety. The weight-based 0.025 mg/kg anchor and the fixed-µg informal practice do not reconcile cleanly, and neither is supported by modern dose-response data. Any engine model built on these numbers is a research scaffold, not prescribing guidance.

⚠ UV / photoprotection warning MT-II darkening is not protection. Combining MT-II with UV exposure or tanning beds increases skin-cancer risk and may encourage riskier UV behavior. Do not present MT-II as a way to "tan safely" or skip sunscreen. Source / purity is the dominant practical risk: use only third-party-tested product (HPLC ≥98%, sterility, endotoxin, identity by MS) — though "verified source" does not make an unapproved drug safe or legal.

Status

Early double-blind, placebo-controlled crossover studies documented erectogenic effects after SC dosing. Wessells 1998: 8/10 men with psychogenic ED had erections at 0.025 mg/kg. Wessells 2000: organic-risk ED — 12/19 MT-II injections produced erections vs 1/21 placebo; mean >80% tip rigidity ~45 min.

Historical dose anchor

0.025 mg/kg SC was the dose used in both ED crossover studies (≈1.75 mg @ 70 kg). No approved starting dose exists; MT-II itself was never approved for ED.

Escalation

No approved titration. Severe nausea occurred in a meaningful minority of subjects even around the historical 0.025 mg/kg dose — a key reason development shifted to the more selective derivative.

Exposure ladder (model labels)

Do not build a consumer ladder. Show only historical trial anchor (0.025 mg/kg) and not recommended outside research / clinical trial.

Monitoring

Nausea severity, yawning, flushing, blood pressure / heart rate, erection duration, priapism threshold, and sexual-desire changes.

Hard stop

Erection > 4 hours = emergency. Ischemic priapism after MT-II is documented and can require cavernosal aspiration, intracavernosal phenylephrine, or surgical decompression; delay risks permanent erectile tissue damage. Also stop for chest pain, severe headache, neurologic symptoms, or severe allergic reaction.

Why MT-II isn't the right tool

Bremelanotide (PT-141 / Vyleesi), the MC4R-focused derivative developed from this exact MT-II biology, is FDA-approved for hypoactive sexual desire disorder in premenopausal women and has defined dosing and safety data — the appropriate regulated path for melanocortin sexual-function effects, whereas MT-II remains unapproved and nonselective.

Mechanistic basis

Vemulapalli 2001: central MC-receptor activation by MT-II produces erection in rats independent of peripheral input; Hadley 2005 framed the MT-II human data as the discovery that a melanocortin regulates sexual function.

⚠ Priapism is the defining acute danger The same circuit that produces an erection produces priapism at the dose-response tail. Any erection persisting beyond ~4 hours is a urological emergency. Co-ingestion (alcohol, PDE5 inhibitors, stimulants) raises risk. This is not a route to self-administer recreationally.

Why this is shown as a warning only

Intranasal melanotan products are widely sold in unregulated markets but are not validated as a safe medical route. The Intrasigna engine deliberately does not provide a starting dose, escalation, or ladder for this route — it exists here only as an unsupported-route warning card.

Dose delivery

Highly variable and unquantifiable — nasal absorption of a 1024 Da peptide is erratic, so "doses" cannot be modeled. Product sterility, purity, and actual peptide content are not assured.

Added risks

All systemic and dermatologic risks of MT-II plus nasal irritation and unknown absorption variability. The same hard stops apply (priapism, lesion change, severe systemic symptoms).

⚠ Not modeled No dose ladder, calculator mapping, or titration logic is provided for the intranasal route. It is unsupported.

Why this is shown as a warning only

Unregulated products appear in tablet / drop forms, but credible route-specific human efficacy or safety dosing is not established. Oral peptides of this size face extensive GI degradation; bioavailability is unknown and likely poor and erratic.

Dose

Not established. The engine does not model active oral dosing for MT-II.

Risks

Same systemic exposure risks if any absorption occurs, plus unknown bioavailability and product-identity uncertainty.

⚠ Not modeled No oral dose ladder or calculator mapping is provided. Unsupported.

Why this is shown as a warning only

Topical/cream melanotan products appear in regulatory warnings but are not supported by validated human MT-II protocol data. Transdermal delivery of a large peptide is inefficient and unquantified.

Dose

Not established. Not modeled as an active protocol.

Risks

Local irritation, pigmentation changes, and unknown systemic absorption.

⚠ Not modeled No topical dose ladder or calculator mapping is provided. Unsupported.

Global exposure bands · research-model · NOT recommended use

Research-model exposure bands & weight-band interpolation.

For the subcutaneous route only. Bands are expressed as research-model exposures, never recommendations. The historical human anchor is ≈ 25 µg/kg/day (0.025 mg/kg) from Dorr/Wessells — for a 70 kg adult, ≈1,750 µg. The conservative band below sits under the historical anchor and exists only for modeling; the high band sits above the direct human anchor and should never be presented as a protocol. All values are evidence grade D/P for use; only the historical anchor carries a B human-signal grade.

Band	µg/kg equivalent	≈ exposure @ 70 kg	Basis	Grade
Conservative research-model	1–5 µg/kg	70–350 µg	Below historical trial anchor; modeling only, not validated. Overlaps the informal "low-dose loading" range, which is not a medical protocol.	D/P
Historical human-study anchor	25 µg/kg	1,750 µg	Early human tanning study recommended single dose and ED crossover dose ≈ 0.025 mg/kg.	B (signal)
High / above-anchor	>25 µg/kg	>1,750 µg	Above the direct early-human anchor; flag as off-model "experimental." 0.03 mg/kg produced somnolence/fatigue in trial subjects; higher amounts raise priapism / systemic-toxicity risk.	D · avoid

Weight-band interpolation · SC historical anchor (math only)

Body weight	Historical anchor (25 µg/kg)	≈ total exposure	UI label
~55 kg (121 lb)	55 × 25 µg	1,375 µg	"Historical exposure equivalent — not a recommended dose."
~65 kg (143 lb)	65 × 25 µg	1,625 µg
~75 kg (165 lb)	75 × 25 µg	1,875 µg
~85 kg (187 lb)	85 × 25 µg	2,125 µg
~95 kg (209 lb)	95 × 25 µg	2,375 µg
~105 kg (231 lb)	105 × 25 µg	2,625 µg

These totals reconstruct the historical mg/kg anchor only; they are not a recommendation. Informal practice usually ignores body weight entirely and uses fixed micro-doses far below these totals — neither approach is validated. No pediatric, pregnancy, renal-, or hepatic-stratified dosing exists, and MT-II should not be modeled for any of those populations.

Titration & hard-stop logic · engine-ready decision rules

Hold, stop & hard-stop logic.

For MT-II the engine is weighted toward stopping, not escalating. Unlike benign peptides, MT-II carries documented serious events (priapism, lesion change, systemic toxicity), so the decision table below is dominated by hold and hard-stop rules. Hard stops are non-editable, reflecting both regulatory caution and observed events.

Trigger	Action	Rationale	Grade
Nausea, vomiting, severe flushing, dizziness	Hold / stop model	Common adverse effects in human and post-market reports.	B/D
New / changing / darkening mole, irregular border or color	Hard stop + dermatology evaluation	Pigmented-lesion change is the central dermatologic warning and a melanoma-surveillance hazard.	D · hard
Erection > 4 hours	Emergency / urgent urological care	Ischemic priapism is documented; delay risks permanent tissue damage.	C/D · hard
Chest pain, severe headache, neurologic symptoms, dark urine / flank pain	Hard stop / urgent evaluation	Case reports include renal infarction; systemic sympathomimetic toxicity with rhabdomyolysis is reported.	C/D · hard
Personal/family melanoma history or dysplastic nevi	Avoid model entirely	Mechanistic + dermatologic risk concentration.	D · hard
Pregnancy / breastfeeding	Avoid model entirely	No safety data; melanocortin/autonomic effects unstudied in pregnancy.	D · hard
Competitive athlete	Verify / likely avoid	Unapproved pharmacologic substances create anti-doping risk under non-approved-substance logic.	D
Desire to "tan without UV / skip sunscreen"	Correct the misconception	MT-II is not sunscreen; tanning behavior itself raises skin-cancer risk.	D

There is deliberately no "escalate" row equivalent to the benign-peptide pages: for an unapproved nonselective melanocortin agonist with documented serious events, the engine's safe default is non-escalation. Encode the mole-change, priapism, and serious-systemic rows as non-editable red hard-stops.

Surveillance scaffold · safety-weighted, none MT-II-validated

Surveillance & safety monitoring bundles.

No MT-II trial defines a biomarker endpoint or numeric target. For MT-II the monitoring scaffold is dermatologic-surveillance-first — skin/mole tracking is the highest-value monitor even though it is not an MT-II "biomarker." Each item is flagged validated_for_MTII = false. The engine should treat changing-lesion detection as a stop signal, not a titration input.

Monitor	Purpose	Interpretation / threshold	Validated for MT-II?
Full-body skin exam / dermoscopy	Detect changing pigmented lesions	Any new, changing, bleeding, or irregular lesion → hard stop + dermatology. The single most important monitor.	Clinically relevant; not MT-II-validated
Mole count / nevus photo log	Track pigment change over time	Baseline + serial standardized photos; flag darkening or new lesions.	No · practical surveillance
Blood pressure / heart rate	Autonomic symptoms	Chest pain, palpitations, syncope → stop / urgent care.	No
Nausea severity score	Tolerability	Persistent vomiting / severe nausea → hold.	No
Erection-duration log	Priapism safety trigger	> 4 hours → emergency. Not a biomarker — a safety trigger.	No · safety trigger
Renal function / CK	Serious-event screen	Flank pain, hematuria, dark urine, severe muscle pain → labs + stop. Symptom-triggered only.	No · symptom-triggered
Pregnancy test	Risk exclusion	Positive → do not model exposure.	No · screening
UV-exposure log	Confounder / behavioral risk	Tanning-bed use or burns → counsel; behavioral risk tracker.	No · behavioral

Architecture note: store each monitor with a validated_for_MTII = false flag and a action_class of stop / hold / screen — none of these are titration inputs for MT-II. The dermatologic monitor is the load-bearing safety element of the whole page.

🛑 Mole-change hard-stop · highest priority

If a mole changes, stop and see a dermatologist.

This card overrides every dosing model on the page. Because MT-II stimulates melanocytes, it can darken existing moles and is associated with lesion change — which both raises concern and makes early melanoma harder to spot. Use the ABCDE rule as a stop checklist:

Sign	What to look for
A — Asymmetry	One half of a mole doesn't match the other.
B — Border	Irregular, scalloped, or poorly defined edges.
C — Color	Multiple colors or new darkening — note MT-II darkens moles even without malignancy, which is exactly why surveillance is hard.
D — Diameter	Growing, or larger than ~6 mm.
E — Evolving	Any change in size, shape, color, elevation, itching, or bleeding.

Any of the above → stop modeling exposure and seek dermatologic evaluation. Do not adjust dose to "manage" a lesion.

Historical SC exposure model · NOT a protocol

Visual exposure model: historical anchor only.

Model day 1 ~700 µg0.01 mg/kg Lowest historical entry · tolerability

Alt. days ↑ 0.005mg/kg steps Cautious historical escalation

Anchor ~1,750 µg0.025 mg/kg Recommended future-study single dose

Above anchor ⚠ avoid>0.025 mg/kg Somnolence/fatigue · not modeled

Any time 🛑 STOPlesion / priapism Hard stops override the model

L2 · Reconstitution & dose math

Reconstitution & Dose Calculator

Educational reconstitution math only — outputs are not treatment recommendations and MT-II is unapproved for any use. It is dosed in micrograms (µg); small draw volumes mean precision matters. Verify peptide purity (≥98% HPLC), sterility, endotoxin limits, identity (MS), and storage before any use. The presence of this calculator does not endorse self-administration of an unapproved drug.

Vial size (mg)

BAC water (mL)

Model dose (µg)

Syringe

Concentration

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Draw volume
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Units (U-100)

—

Doses per vial

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Basis

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04 · Combination protocols

Combining Melanotan II — mostly what to avoid.

Unlike benign peptides, the honest "stacking" section for MT-II is dominated by combinations to avoid. MT-II is an unapproved nonselective melanocortin agonist; layering it with UV exposure, other melanocortin agonists, vasoactive agents, or other gray-market injectables compounds risk and makes adverse-event attribution impossible. None of the pairings below are validated combination products. The safest combination involving MT-II is none.

Melanotan II Sun / UV exposure Tanning beds

The most common real-world combination — and a dangerous one. MT-II does not protect against UV; combining it with sun or tanning-bed exposure increases skin-cancer risk and may encourage riskier UV behavior. Melanoma case reports associated with MT-II have coincided with heavy UV / sunbed use. Hard warning: MT-II is not sunscreen and must never be presented as a way to tan "safely."

Scenario	Action	Reason
Using MT-II for a tan	Maintain SPF 30+ regardless	No photoprotection from pigment alone
Adding tanning beds	Avoid entirely	Compounds carcinogenic UV load

Melanotan II Bremelanotide / PT-141 Afamelanotide

Direct mechanistic overlap. Bremelanotide is itself a melanocortin agonist developed from MT-II biology; stacking overlapping melanocortin agonists risks additive nausea, blood-pressure effects, and sexual/autonomic effects, including priapism. Do not combine MT-II with any other melanocortin agonist.

Component	Mechanism	Status
MT-II	Nonselective MC1–5R agonist	Unapproved
Bremelanotide	MC4R-focused agonist	FDA-approved (HSDD)

Melanotan II Sildenafil / tadalafil Alcohol · stimulants

MT-II and PDE5 inhibitors influence erectile physiology through different pathways; combining them adds priapism and hypotension risk. Given that MT-II alone is associated with ischemic priapism, additive erectogenic agents are a clear hazard. Co-ingested stimulants or "pain pills" have featured in serious-toxicity case reports. Not validated; avoid.

Scenario	Action	Reason
MT-II + PDE5i	Avoid	Additive priapism / hypotension
MT-II + stimulants	Avoid	Sympathomimetic-toxicity reports

Melanotan II "Beauty peptide" stacks Unverified research chemicals

MT-II is commonly discussed inside gray-market "beauty peptide" stacks. Stacking multiple unapproved injectables of uncertain purity makes adverse-event causality, sterility, dosing, and interactions impossible to interpret. Hard constraint: do not stack MT-II with other unapproved injectables.

Component	Role	Risk
MT-II	Pigment / sexual signal	Unapproved
Unverified peptides	Varies / unknown	Purity, sterility, interactions

⚠ Hard-constraint clinical note Avoid MT-II exposure entirely in users with active melanoma, prior melanoma, dysplastic nevus syndrome, unexplained changing lesions, or significant family melanoma history. This is not because causality is proven, but because melanocyte stimulation plus lesion-surveillance uncertainty creates an unacceptable risk signal.

Melanotan II vs. the melanocortin family

Agent	Primary use	Receptor profile	Human evidence	Route	Regulatory status
Melanotan II	Pigmentation / tanning research; sexual-function signal	Nonselective MC1R/MC3R/MC4R/MC5R	Small old trials + case reports	SC (trials); unregulated nasal/oral/topical	Not FDA-approved (B signal / D use)
Afamelanotide (Scenesse)	Phototoxicity prevention in erythropoietic protoporphyria (EPP)	MC1R-selective α-MSH analog	Approved-drug RCT evidence	SC implant	FDA / EMA-approved (EPP)
Bremelanotide (Vyleesi / PT-141)	Hypoactive sexual desire disorder (premenopausal women)	MC4R-focused agonist (MT-II-derived)	Approved-drug RCT evidence	SC autoinjector	FDA-approved (HSDD)
Setmelanotide (Imcivree)	Rare genetic obesity (POMC, PCSK1, LEPR)	MC4R agonist	Approved-drug RCT evidence	SC daily	FDA-approved (genetic obesity)
α-MSH (endogenous)	Native pigmentation / appetite / immune signaling	Endogenous melanocortin ligand	Physiologic reference	Endogenous	N/A (hormone)
Melanotan I (= afamelanotide)	Linear α-MSH analog precursor to Scenesse	MC1R-biased	See afamelanotide	SC implant	Approved as afamelanotide

05 · Safety profile & contraindications

A genuinely risky profile; dermatologic & priapism caveats dominate.

Melanotan II has a markedly less reassuring safety profile than most peptides in this atlas. Beyond the common, tolerability-limiting effects (nausea, flushing, yawning), it carries documented serious events — ischemic priapism, systemic sympathomimetic toxicity with rhabdomyolysis, a renal-infarction case report — and a central dermatologic concern around mole change and possible melanoma association. Layered on top is an unregulated supply chain with purity and sterility problems. No long-term human safety data exists; pregnancy, lactation, pediatric, melanoma-risk, and cardiovascular-unstable populations are off-model by default.

Observed / Reported Adverse Events

NauseaOne of the most common effects; reported at most dose levels in human studies and frequently dose-limiting. A meaningful minority experienced severe nausea around the 0.025 mg/kg dose.

Yawning / stretching complexA characteristic stretching–yawning syndrome correlated with onset of spontaneous erections in human trials — a recognized melanocortin behavioral signature.

Flushing / dizziness / fatigue / somnolenceReported across trials and case literature; Grade II somnolence and fatigue occurred at the 0.03 mg/kg level.

Decreased appetiteReported in human studies; consistent with MC4R energy-balance signaling.

Spontaneous / prolonged erection · priapismErections are an expected pharmacodynamic effect; ischemic priapism is documented in multiple case reports, some requiring surgical decompression. Erection > 4 h is an emergency.

Darkening moles / new pigmented lesionsDermoscopic lesion change is documented; melanoma associated with MT-II use is reported (UV-confounded). The central dermatologic concern.

Serious systemic eventsSystemic sympathomimetic toxicity with rhabdomyolysis and renal dysfunction has been reported; a renal-infarction case has been attributed to MT-II. Rare, but serious; causality varies by case.

Product contamination / mislabelingOnline products vary widely in purity, with bacterial endotoxin and unidentified peptide contaminants reported. Much real-world harm traces to product quality, not just pharmacology.

High-Risk Populations & Unknowns

Melanoma history / dysplastic neviMelanocyte-stimulating activity plus lesion-surveillance difficulty creates an unacceptable risk signal. Absolute avoid.

Many atypical moles / family melanoma historySame rationale; the population least able to safely tolerate pigment changes that mask early melanoma. Avoid.

Priapism history / sickle cell diseaseElevated priapism risk with an erectogenic agent. Avoid.

Pregnancy / lactationNo safety data; melanocortin, autonomic, and appetite effects unstudied in pregnancy. Avoid.

Cardiovascular instabilityAutonomic activation, flushing, and BP/HR effects of uncertain magnitude. Avoid / specialist input.

Kidney diseaseA renal-infarction case report and dehydration/vomiting risk raise caution; effects unstudied.

Competitive athletesUnapproved-substance anti-doping risk; verify with anti-doping authority.

Tanning-dependence / body-image behaviorsRisk of compulsive UV / tanning exposure layered on top of MT-II use.

Contraindication reference

Condition / scenario	Risk level	Concern
Active melanoma	Avoid	Potential melanocyte/pigment-pathway stimulation; surveillance hazard.
Prior melanoma	Avoid	Recurrence / surveillance concern.
Dysplastic nevus syndrome	Avoid	Difficult lesion monitoring; many lesions at baseline risk.
Rapidly changing mole	Avoid	Requires dermatology evaluation before any melanocortin exposure.
Pregnancy / breastfeeding	Avoid	No safety data.
Priapism history / sickle cell disease	Avoid	Prolonged-erection risk with an erectogenic agent.
Cardiovascular instability	Caution / Avoid	Autonomic symptoms, flushing, BP/HR uncertainty.
Kidney disease	Caution	Renal case-report concern; dehydration / vomiting risk.
Competitive athlete	Caution / Avoid	Anti-doping / unapproved-substance risk.
Unverified online product	Avoid	Purity, sterility, endotoxin, identity all unassured.
Body dysmorphic / tanning-dependence behaviors	Caution	Risk of compulsive UV / tanning exposure.
Desire to skip sun protection	Counsel	MT-II is not sunscreen and does not make UV safe.

Surveillance for anyone exposed to MT-II (research / harm-reduction framing)

Baseline

Full-body skin exam with photo / dermoscopy of all moles; personal and family melanoma history; cardiovascular review; pregnancy test if applicable. Establish a lesion baseline before any exposure — this is the highest-value step.

Dermatologic (ongoing)

Serial standardized mole photography; ABCDE self-checks. Any new, changing, darkening, or irregular lesion → stop and seek dermatology. Do not adjust dose to "manage" a lesion.

Each exposure

Nausea / vomiting, flushing, dizziness, blood pressure / heart-rate symptoms, appetite change, and erection duration. Persistent severe symptoms → hold / stop.

Emergency triggers

Erection > 4 hours; chest pain; severe headache or neurologic symptoms; dark urine, flank pain, or severe muscle pain (rhabdomyolysis / renal concern); severe allergic reaction. Seek urgent care.

Symptom-triggered labs

Renal function and CK if flank pain, dark urine, or severe muscle symptoms; otherwise no validated routine MT-II lab panel exists.

Stop / hold criteria

Any changing pigmented lesion, priapism, serious systemic event, new pregnancy, new melanoma-risk diagnosis, or evidence of contaminated product. The safe default for MT-II is to stop, not to titrate.

06 · Key studies & evidence base

Small, old human signals; no modern safety trials.

Melanotan II has real human pharmacodynamic signals — pigmentation and erection — but the evidence base is small, decades old, and never matured into modern long-term safety trials. The strongest defensible claims are "MT-II increases pigmentation" and "MT-II can initiate erections in some men." The weakest and riskiest claims are "safe tanning," "skin-cancer prevention," "routine cosmetic use," "intranasal protocols," and "long-term safety." Regulatory and dermatology sources strongly support warning language against unapproved consumer use.

B Human pilot · tanning · SC

Dorr et al. 1996 — pilot Phase I tanning study (Life Sci)

A single-blind, alternating-day, placebo-controlled trial in 3 normal male volunteers starting at 0.01 mg/kg SC, escalated by 0.005 mg/kg to 0.025–0.03 mg/kg, five doses over 2 weeks. Increased facial/upper-body/buttock pigmentation by quantitative reflectance; the 0.03 mg/kg level caused Grade II somnolence/fatigue; mild nausea at most levels; recommended future single dose 0.025 mg/kg/day. The foundational human tanning demonstration.

PMID 8637402

B Human crossover · psychogenic ED

Wessells et al. 1998 — erections in psychogenic ED (J Urol)

A double-blind, placebo-controlled crossover study: 0.025 mg/kg SC MT-II initiated erections in 8 of 10 men with psychogenic erectile dysfunction, with RigiScan-quantified rigidity; side effects included nausea, yawning, and decreased appetite. First controlled human demonstration of MT-II's erectogenic effect.

PMID 9679884

B Human crossover · organic ED

Wessells et al. 2000 — organic-risk ED crossover (Urology)

Ten men with organic ED risk factors in a double-blind crossover received 0.025 mg/kg SC MT-II or vehicle twice each, with RigiScan monitoring over 6 hours: erections occurred in 12 of 19 MT-II injections vs 1 of 21 placebo; mean >80% tip rigidity lasted ~45 min (vs 1.9 min placebo); self-reported sexual desire increased. Extended the erectogenic signal beyond psychogenic ED.

PMID 11018622

B Human review · sexual function

Wessells et al. 2000 — human MT-II review (Int J Impot Res)

A review of the human melanocortin/MT-II sexual-function program summarizing erectile and desire outcomes across the Arizona studies and documenting that severe nausea occurred in a notable minority around the 0.025 mg/kg dose — a key tolerability finding that pushed development toward more selective derivatives.

PMID 11035391

P Preclinical · central erection

Vemulapalli et al. 2001 — central MC-receptor erection (Neuroscience)

Demonstrated that activation of central melanocortin receptors by MT-II results in penile erection in rats, localizing the erectogenic mechanism to central (hypothalamic/spinal) melanocortin circuitry rather than peripheral vascular action. Mechanistic anchor for the human erectile findings.

PMID 11591452

C Case report · priapism

Mallory et al. 2021 — MT-II priapism (Sex Med) + prior cases

An acute ischemic priapism after SC MT-II managed with penoscrotal decompression after failed aspiration/phenylephrine; the report notes only two prior MT-II priapism cases — Dreyer (surgical shunt) and Nelson (priapism with systemic sympathomimetic toxicity). Establishes priapism as a recognized, if uncommon, serious effect.

Sex Med 2021

C Case report · melanoma / lesions

Hjuler 2014 & Sivyer 2013 — pigmented-lesion change & melanoma

Hjuler 2014 (JAAD) reported melanoma associated with MT-II use; Sivyer 2013 documented dermoscopic change in melanocytic lesions induced by melanotan. Both note UV/sunbed confounding, so causality is unresolved — but the lesion-surveillance hazard is real and is the basis for the dermatologic hard-stop.

PMID 24355990 PMC3663356

C Case report · renal / systemic

Renal infarction & systemic toxicity case reports

A case of renal infarction was attributed to MT-II, and an MT-II injection produced systemic sympathomimetic toxicity with rhabdomyolysis and renal dysfunction requiring ICU care. Rare but serious; reinforce that "more" is dangerous and that co-ingestants raise risk.

PMC7148395

D Regulatory · status

Regulatory landscape — FDA / TGA / unapproved status

The FDA has not approved MT-II for any indication and has treated marketed melanotan products as unapproved new drugs, issuing public warnings citing serious adverse events. Australia's TGA states supplying melanotan tanning products without a prescription is illegal. Independent purity analyses found many online samples failed claimed purity, with endotoxin and unidentified-peptide contamination.

TGA

A Approved derivatives · context

Afamelanotide & bremelanotide — the regulated successors

Afamelanotide (a melanocortin α-MSH analog, "Melanotan I") is approved for phototoxicity mitigation in erythropoietic protoporphyria; bremelanotide (PT-141 / Vyleesi), an MC4R-focused agonist developed from MT-II biology, is FDA-approved for hypoactive sexual desire disorder in premenopausal women. These show the regulated path that MT-II itself never completed.

DrugBank · afamelanotide

D Registered trial · vitiligo

Registered vitiligo-adjunct trial (ClinicalTrials.gov)

A ClinicalTrials.gov listing exists for MT-II as an adjunct to NB-UVB phototherapy for stable nonsegmental vitiligo. This is a registered/active research context only — not proof of approved use or established efficacy, and not a basis for general use.

ClinicalTrials.gov

D Evidence gap

Translational gap — no modern safety RCT

As of May 2026, no large, modern, well-controlled trial defines a safe dose or long-term safety profile for MT-II in any indication. Early melanogenic-drug development (Hadley/Hruby) characterized MT-II as a superpotent α-MSH analog, but development of MT-II itself was not carried to approval. The unresolved questions — long-term melanoma risk, cardiovascular/renal safety, and the real-world harm of contaminated unregulated product — are exactly why regulatory and dermatology guidance is to avoid it.

PubMed

Read-out signal

Melanotan II is a paradox: a peptide with authentic, double-blind human pharmacodynamic effects (pigmentation, erection) that nonetheless should not be used recreationally. Its development was abandoned in favor of selective successors precisely because the nonselective profile produces nausea, autonomic effects, priapism, and pigment changes that cannot be separated from the desired effect. The most defensible position is the regulatory one: MT-II is unapproved, its supply chain is unregulated and frequently contaminated, and the dermatologic and priapism risks are concrete. Where melanocortin effects are genuinely wanted, the regulated successors — afamelanotide for photoprotection in EPP, bremelanotide for HSDD — are the appropriate, studied tools.

07 · Compare & contrast

Adjacent melanocortin agents.

08 · Evidence & references

Every claim, graded and sourced.

A · RCT / approved-drug evidence

B · Controlled human trial (small)

C · Case report / mechanistic

P · Preclinical / animal

D · Expert / regulatory / database

Explore the ATLAS index

Melanotan IIMT-II · the melanocortin "tanning peptide" · pigmentation & sexual-function signal

Key facts & headline data.

How a melanocortin agonist works.

MC1R · melanogenesis / eumelanin pathway

MC3R / MC4R · central sexual arousal & erection

MC4R · appetite / satiety signaling

Autonomic / sympathetic activation

Nevus / pigmented-lesion change

Peripheral / MC5R & inflammatory signaling

Historical exposure architecture — not recommended protocols.

Research-model exposure bands & weight-band interpolation.

Weight-band interpolation · SC historical anchor (math only)

Hold, stop & hard-stop logic.

Surveillance & safety monitoring bundles.

If a mole changes, stop and see a dermatologist.

Visual exposure model: historical anchor only.

Reconstitution & Dose Calculator

Combining Melanotan II — mostly what to avoid.

Melanotan II vs. the melanocortin family

A genuinely risky profile; dermatologic & priapism caveats dominate.

Contraindication reference

Surveillance for anyone exposed to MT-II (research / harm-reduction framing)

Small, old human signals; no modern safety trials.

Dorr et al. 1996 — pilot Phase I tanning study (Life Sci)

Wessells et al. 1998 — erections in psychogenic ED (J Urol)

Wessells et al. 2000 — organic-risk ED crossover (Urology)

Wessells et al. 2000 — human MT-II review (Int J Impot Res)

Vemulapalli et al. 2001 — central MC-receptor erection (Neuroscience)

Mallory et al. 2021 — MT-II priapism (Sex Med) + prior cases

Hjuler 2014 & Sivyer 2013 — pigmented-lesion change & melanoma

Renal infarction & systemic toxicity case reports

Regulatory landscape — FDA / TGA / unapproved status

Afamelanotide & bremelanotide — the regulated successors

Registered vitiligo-adjunct trial (ClinicalTrials.gov)

Translational gap — no modern safety RCT

Adjacent melanocortin agents.

Every claim, graded and sourced.

More Hormone / Reproductive peptides & tools.