Melanotan II Dosage Guide

Evidence-based loading and maintenance protocols for the non-selective melanocortin agonist — tanning, sexual function, nausea management, mole monitoring, and safety.

Compiled by PeptideWiki Editorial Team·Last reviewed February 24, 2026

What Is Melanotan II?

Melanotan II (MT-II) is a synthetic cyclic lactam heptapeptide analog of alpha-melanocyte stimulating hormone (α-MSH). Its amino acid sequence is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2. MT-II was originally developed at the University of Arizona by Dr. Victor Hruby and colleagues as a potential tanning agent to reduce skin cancer risk by stimulating the body's natural melanin production without excessive UV exposure.

What makes Melanotan II unique — and controversial — is its non-selective activation of melanocortin receptors. Unlike Melanotan I (afamelanotide), which selectively targets MC1R for tanning, MT-II activates MC1R through MC5R. This broad receptor profile produces multiple effects: skin tanning via MC1R-driven melanogenesis, sexual arousal and erectile function via MC3R/MC4R activation in the hypothalamus, appetite suppression via MC4R signaling in energy homeostasis pathways, and potential fat loss through altered energy balance.

The sexual function effects of MT-II were so pronounced in early clinical trials that they led to the development of PT-141 (bremelanotide) — a derivative of MT-II specifically optimized for MC4R activation. PT-141 is now FDA-approved as Vyleesi for hypoactive sexual desire disorder (HSDD) in premenopausal women, making it the only melanocortin-based drug approved for sexual function.

Use our Peptide Dosage to calculate your exact dose based on vial size and concentration.

Important: Melanotan II is NOT FDA-approved for human use. It is classified as a research peptide. Melanotan I (afamelanotide/Scenesse) IS FDA-approved for erythropoietic protoporphyria (EPP), but that is a different peptide. All dosing information in this guide is derived from clinical studies and community protocols — not from approved pharmaceutical labeling. Consult a healthcare provider before using any research peptide.

Key Characteristics:

Non-selective melanocortin agonist — activates MC1R through MC5R, producing tanning, sexual arousal, appetite suppression, and energy homeostasis effects
Cyclic heptapeptide — Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 — cyclic structure provides enhanced receptor binding and metabolic stability
Primary effect: melanogenesis — MC1R activation stimulates melanocytes to produce eumelanin (brown/black pigment), darkening the skin with minimal UV exposure
Sexual function effects — MC3R/MC4R activation in the hypothalamus increases libido, sexual arousal, and erectile function — the basis for PT-141 development
Appetite suppression — MC4R activation in energy homeostasis pathways reduces appetite and may contribute to fat loss over time
Half-life ~2–3 hours — effects on melanogenesis are cumulative; tanning develops over days to weeks of loading

For a complete overview of its mechanism and research, see our full Melanotan II profile. Interested in the sexual function derivative? See the PT-141 Dosage Guide. New to peptides? Start with the Beginner's Guide to Peptides.

How Melanotan II Dosage Is Determined

Melanotan II dosing is derived from Phase I/II clinical trials conducted at the University of Arizona and subsequent studies, supplemented by extensive community experience accumulated over two decades of use. The loading-then-maintenance approach is well-established and reflects the pharmacodynamics of melanogenesis — melanin production must be “primed” with consistent stimulation before it can be sustained with infrequent dosing.

Clinical Dose-Response Studies

Early clinical trials at the University of Arizona demonstrated that subcutaneous MT-II at doses of 0.01–0.025 mg/kg produced measurable increases in skin melanin density (measured by reflectance spectrophotometry) within 5–14 days. Dose-dependent tanning was observed, with higher doses producing faster and darker results but also more pronounced side effects — particularly nausea. These studies established the therapeutic window: doses below 0.25 mg produce minimal tanning; doses above 1 mg per injection produce diminishing returns with substantially increased nausea and flushing.

Loading vs. Maintenance Pharmacology

Melanogenesis is not an instantaneous process. MT-II activates MC1R on melanocytes, upregulating tyrosinase and other enzymes in the melanin synthesis pathway. This “priming” requires consistent daily stimulation over 2–4 weeks to produce visible results. Once melanocytes are fully activated and melanin levels are elevated, much less frequent dosing (1–2x per week) is sufficient to maintain the tan. This biological reality is the basis for the loading/maintenance protocol.

Nausea and Side Effect Profile

Nausea is the dose-limiting side effect of MT-II. Clinical studies confirmed that nausea is caused by central melanocortin receptor activation (MC3R/MC4R) in brainstem emetic centers. It is dose-dependent and most severe during the first 3–7 days of use, after which tolerance develops. The standard practice of starting at 0.25 mg and injecting before bed was developed to minimize this initial nausea period. Some users also take an antihistamine (such as diphenhydramine or cetirizine) 30 minutes prior to injection to reduce nausea and flushing.

Strength of evidence: Moderate. MT-II has Phase I/II clinical trial data from the University of Arizona, published peer-reviewed studies on melanogenesis and sexual function, and over 20 years of community experience. However, large-scale Phase III trials were never completed, long-term safety data is limited, and the peptide has never received FDA approval. Dosing protocols are based on clinical pharmacology studies and extensive community experience.

Standard Melanotan II Dosage Ranges

Melanotan II is administered by subcutaneous injection, typically in the abdominal fat pad. Dosing follows a two-phase protocol: a daily loading phase to initiate melanogenesis, followed by a reduced-frequency maintenance phase. All doses below are in milligrams (mg), not micrograms. MT-II is dosed in the 0.25–1 mg range, which is significantly higher than most peptides dosed in micrograms.

Loading Phase

Level	Dose per Injection	Frequency	Duration	Notes
Starting / Conservative	0.25 mg	Once daily (before bed)	2–4 weeks	Recommended for all users; minimizes nausea and flushing while assessing tolerance
Standard	0.5 mg	Once daily (before bed)	2–3 weeks	Most common loading dose after initial tolerance assessment; faster results but more nausea
Aggressive	0.5–1 mg	Once daily (before bed)	1–2 weeks	For experienced users who tolerate MT-II well; significant nausea likely at 1 mg; not recommended for first-time users

Maintenance Phase

Approach	Dose per Injection	Frequency	Notes
Minimal Maintenance	0.5 mg	Once per week	Sufficient for most users to sustain tan with occasional UV exposure
Standard Maintenance	0.5–1 mg	1–2x per week	Most common; sustains a deep tan with minimal UV; good for year-round maintenance
As-Needed	0.5–1 mg	Before planned UV exposure	Some users inject only before sun or tanning sessions; less consistent but effective for seasonal use

Injection Timing

Before bed is the gold standard: Injecting 30–60 minutes before sleep allows you to sleep through the peak nausea period (30–90 minutes post-injection)
On an empty or light stomach: A full stomach can worsen nausea. Inject at least 1–2 hours after eating
UV exposure timing: For maximum tanning effect, get brief UV exposure (10–20 minutes) the day after injection or within 24 hours of the dose
Consistency during loading: Daily injection at the same time during the loading phase produces the most uniform results

Start at 0.25 mg. Nausea from MT-II is nearly universal at initiation. Starting at 0.5 mg or higher without first assessing tolerance is the most common mistake and leads to severe nausea, facial flushing, and in some cases vomiting. Start low. You can always increase after 3–5 days once tolerance has developed.

Melanotan II vs Melanotan I Comparison

Melanotan II and Melanotan I are often confused, but they are structurally and pharmacologically distinct peptides with very different receptor profiles, effects, side effects, and regulatory statuses. This comparison clarifies the key differences.

Parameter	Melanotan II (MT-II)	Melanotan I (Afamelanotide)
Structure	Cyclic heptapeptide (7 amino acids)	Linear tridecapeptide (13 amino acids)
Receptor Selectivity	Non-selective (MC1R–MC5R)	MC1R-selective (tanning only)
Tanning Effect	Strong (MC1R)	Strong (MC1R)
Sexual Function Effects	Yes (MC3R/MC4R — increased libido, erections)	Minimal to none (MC1R-selective)
Appetite Suppression	Yes (MC4R)	Minimal
Nausea	Common and significant (MC3R/MC4R)	Mild (less central receptor activation)
Facial Flushing	Common	Less common
Administration	Subcutaneous injection (daily → weekly)	Subcutaneous implant (monthly, clinical setting)
FDA Status	NOT approved (research peptide)	FDA-approved as Scenesse for EPP
Best For	Tanning + sexual function + appetite control	Tanning only, with fewer side effects

Key takeaway: If your sole goal is tanning with minimal side effects, Melanotan I (afamelanotide) is the cleaner option — it is MC1R-selective, has fewer systemic effects, and is actually FDA-approved (for EPP). If you want the combined tanning + sexual function + appetite suppression effects, Melanotan II provides all three but with a more complex side effect profile. For sexual function specifically, consider PT-141 (bremelanotide), which is MC4R-optimized and FDA-approved for HSDD.

Calculate Your Melanotan II Dose

Melanotan II is supplied as a lyophilized (freeze-dried) powder, typically in 10 mg vials. You reconstitute it with bacteriostatic water, then draw your dose using an insulin syringe. The concentration depends on how much water you add to the vial. Because MT-II is dosed in milligrams (not micrograms like most peptides), volumes are typically larger per injection.

Worked Example:

Vial size: 10 mg (10,000 mcg) of Melanotan II
Bacteriostatic water added: 2 mL
Concentration: 10 mg ÷ 2 mL = 5 mg per mL
Target dose: 0.5 mg
Volume to draw: 0.5 ÷ 5 = 0.1 mL = 10 units on an insulin syringe

Quick Reference — 10 mg Vial

Bac Water Added	Concentration	0.25 mg Dose	0.5 mg Dose	1 mg Dose
1 mL	10 mg/mL	2.5 units (0.025 mL)	5 units (0.05 mL)	10 units (0.1 mL)
2 mL	5 mg/mL	5 units (0.05 mL)	10 units (0.1 mL)	20 units (0.2 mL)
2.5 mL	4 mg/mL	6.25 units (0.0625 mL)	12.5 units (0.125 mL)	25 units (0.25 mL)
5 mL	2 mg/mL	12.5 units (0.125 mL)	25 units (0.25 mL)	50 units (0.5 mL)

Practical tip: Adding 2 mL of bacteriostatic water to a 10 mg vial gives a clean 5 mg/mL concentration, making dose calculations straightforward — 0.25 mg = 5 units, 0.5 mg = 10 units, 1 mg = 20 units. This is the most popular reconstitution volume for MT-II.

Skip the Math — Use Our

Enter your vial size, water volume, and desired dose — get instant calculations with zero manual math.

Melanotan II Dosage by Goal

Melanotan II's non-selective melanocortin receptor profile means it produces multiple simultaneous effects. The optimal protocol varies depending on whether your primary goal is tanning, sexual function enhancement, appetite suppression, or a combination. All goals share the same loading/maintenance structure, but dose emphasis and timing differ.

Skin Tanning (Primary Use)

The most common use case. MT-II activates MC1R on melanocytes, upregulating eumelanin (brown/black pigment) production. The goal is to build a deep, even tan with minimal UV exposure. Fair-skinned individuals (Fitzpatrick I–II) will need a longer loading phase; those with medium skin tones (Fitzpatrick III–IV) respond faster.

Loading dose: 0.25–0.5 mg SubQ daily for 2–4 weeks
Maintenance dose: 0.5–1 mg once or twice per week
UV exposure: 10–20 minutes of natural sun or low-intensity tanning 3–5x per week during loading; 1–2x per week during maintenance
Timing: Inject before bed; get UV exposure the following day
Timeline: Visible darkening typically within 7–14 days; full tan development at 3–4 weeks

Sexual Function Enhancement

MT-II's activation of MC3R and MC4R in the hypothalamus produces increased libido, sexual arousal, and in men, enhanced erectile function. These effects are dose-dependent and typically noticeable within 1–4 hours of injection. For users primarily seeking sexual function benefits, PT-141 (bremelanotide) may be more appropriate as it is MC4R-optimized with less tanning effect. However, some users prefer MT-II for the combined tanning + sexual function profile.

Dose: 0.5–1 mg SubQ, 1–4 hours before sexual activity
Frequency: As-needed basis, typically no more than 2–3x per week
Onset: Sexual effects typically begin 1–4 hours post-injection and can last 6–12 hours or longer
Note: Spontaneous erections are a common “side effect” during the loading phase — be aware if dosing during daytime hours

Appetite Suppression & Body Composition

MC4R activation by MT-II reduces appetite through central energy homeostasis pathways. This effect is consistent but secondary to the tanning and sexual function effects. Some users report meaningful appetite reduction and gradual fat loss over the course of an MT-II cycle. This is best viewed as a beneficial side effect rather than a primary indication — dedicated weight loss peptides like Semaglutide or Tirzepatide are far more effective for weight management.

Dose: Standard loading and maintenance protocol (0.25–0.5 mg daily loading, 0.5–1 mg 1–2x/week maintenance)
Note: Appetite suppression is dose-dependent and most pronounced during the loading phase
Note: For dedicated weight loss, consider Semaglutide, Tirzepatide, or Retatrutide — these are far more effective for this purpose

Combined Tanning + Sexual Function

Many users choose MT-II specifically for this combination. The loading phase achieves both melanogenesis initiation and provides strong sexual function enhancement. Maintenance dosing sustains the tan while providing ongoing libido benefits. This is the most common “real-world” use case.

Loading dose: 0.25–0.5 mg SubQ daily for 2–4 weeks (before bed)
Maintenance dose: 0.5–1 mg 1–2x per week — ideally timed to coincide with both UV exposure and planned sexual activity
Cycling: Some users cycle 8 weeks on, 4 weeks off; others maintain indefinitely with weekly dosing

All effects are dose-dependent. Tanning, sexual function, appetite suppression, and side effects (nausea, flushing) all increase with dose. Start conservatively at 0.25 mg and increase based on your individual response and tolerance. There is no benefit to rushing the loading phase — melanogenesis takes time regardless of dose.

Nausea Management

Nausea is the most significant barrier to Melanotan II use. It is caused by melanocortin receptor activation (MC3R/MC4R) in the central nervous system — specifically the area postrema and nucleus of the solitary tract, brain regions responsible for the vomiting reflex. Nearly every MT-II user experiences nausea during the first few injections. Proper management makes the difference between an intolerable experience and a manageable one.

Nausea is nearly universal at initiation. Do not be alarmed. It is the single most common side effect of MT-II and is expected. Tolerance develops within 3–7 days for most users. The strategies below dramatically reduce its impact.

Nausea Reduction Strategies

Start at 0.25 mg (non-negotiable) — Nausea is dose-dependent. Starting at 0.5 mg or higher dramatically increases nausea severity. Begin at 0.25 mg for the first 3–5 days, then increase to 0.5 mg once tolerance has developed.
Inject before bed — The gold standard timing. Peak nausea occurs 30–90 minutes post-injection. Injecting 30–60 minutes before sleep allows you to fall asleep before nausea peaks, effectively sleeping through the worst of it.
Inject on an empty or light stomach — A full stomach worsens nausea significantly. Inject at least 1–2 hours after your last meal. A completely empty stomach is ideal for most users.
Antihistamine pre-treatment (optional) — Taking an antihistamine (diphenhydramine 25–50 mg or cetirizine 10 mg) 30 minutes before injection can reduce both nausea and facial flushing. Diphenhydramine has the added benefit of promoting sleepiness, complementing the before-bed injection strategy.
Ginger for natural anti-nausea support — Ginger supplements (500–1,000 mg) or ginger tea taken 30 minutes before injection provide mild anti-emetic effects. Many users find this sufficient when combined with low starting doses and before-bed timing.
Gradual dose escalation — If 0.25 mg produces manageable nausea, stay at that dose for 5–7 days before increasing. If 0.25 mg produces severe nausea, try 0.1–0.15 mg for the first week. There is no rush. Slower escalation means less suffering with the same end result.

Nausea Timeline

Day	Typical Nausea Severity	Notes
Day 1–2	Most intense	Peak nausea; some users experience mild vomiting. Before-bed injection is critical.
Day 3–5	Moderate	Noticeable improvement. Nausea still present but shorter in duration and less intense.
Day 5–7	Mild	Most users have developed significant tolerance by this point. Nausea may be brief or absent.
Day 7+	Minimal or absent	Tolerance is established. Dose can be increased if desired. Nausea may briefly return when increasing dose.

If nausea persists beyond 10–14 days at the starting dose, you may be unusually sensitive to central melanocortin activation. Reduce the dose to 0.1 mg and escalate very slowly (0.05 mg increments every 5–7 days). Some individuals simply have lower tolerance for MC3R/MC4R stimulation. If nausea remains intolerable at very low doses, MT-II may not be appropriate for you — consider Melanotan I as a tanning-only alternative with less nausea.

Melanotan II Stacking Protocols

Melanotan II is most commonly used as a standalone compound, given its multi-receptor effects. However, targeted stacking can enhance specific outcomes. The most relevant combinations pair MT-II with peptides that complement its effects or address recovery and overall health.

Melanotan II + PT-141 — Enhanced Sexual Function + Tanning

For users who want maximum sexual function enhancement alongside tanning. MT-II provides broad melanocortin activation (tanning + baseline sexual function), while PT-141 (bremelanotide) adds targeted MC4R activation for on-demand sexual function. This combination is typically used during the maintenance phase, with PT-141 injected as-needed rather than daily.

Compound	Dose	Frequency	Purpose
Melanotan II	0.5–1 mg SubQ	1–2x per week (maintenance)	Sustained tanning + baseline sexual function + appetite control
PT-141	1.75 mg SubQ	As-needed, 1–4 hours before activity	On-demand MC4R activation for enhanced sexual response

Protocol note: Do not use MT-II and PT-141 on the same day. Both activate melanocortin receptors, and combining them increases the risk of nausea, flushing, and blood pressure changes. Use MT-II for your regular maintenance schedule and PT-141 on separate days when on-demand sexual function is desired.

Melanotan II + BPC-157 (Tanning + Tissue Repair)

For users combining an MT-II tanning cycle with injury recovery. BPC-157 provides localized tissue repair through angiogenesis and growth factor upregulation, operating through entirely different pathways than MT-II. There is no pharmacological interaction between the two, making this a straightforward combination.

Compound	Dose	Frequency	Purpose
Melanotan II	0.25–0.5 mg SubQ	Daily during loading; 1–2x/week maintenance	Melanogenesis, tanning, sexual function
BPC-157	250 mcg SubQ	1–2x daily (near injury site)	Localized tissue repair, angiogenesis, gut healing

Melanotan II + Ipamorelin/CJC-1295 (Tanning + GH Support)

Some users combine MT-II with growth hormone secretagogues for a comprehensive protocol covering tanning, body composition, recovery, and sleep quality. Ipamorelin + CJC-1295 provide pulsatile GH release for muscle recovery, fat metabolism, and anti-aging benefits, while MT-II handles tanning and sexual function. The peptides target entirely different receptor systems with no pharmacological overlap.

Compound	Dose	Frequency	Purpose
Melanotan II	0.25–0.5 mg SubQ	Daily (loading) or 1–2x/week (maintenance)	Tanning, sexual function, appetite suppression
Ipamorelin	200–300 mcg SubQ	1–2x daily (fasted)	GH pulse for recovery, body composition, sleep
CJC-1295 (no-DAC)	100 mcg SubQ	At each Ipamorelin injection	Amplifies and sustains GH pulse (GHRH receptor)

Timing note: MT-II is best injected before bed. Ipamorelin/CJC-1295 should be injected fasted (morning and/or before bed). If you inject both Ipamorelin and MT-II before bed, use separate syringes and injection sites. Do not mix peptides in the same syringe unless you have confirmed compatibility.

Explore more combinations with our Peptide Stack Builder or browse the Top 10 Peptide Stacks guide.

Safety, Side Effects & Contraindications

Safety Profile: Melanotan II has a more complex safety profile than most cosmetic peptides due to its non-selective melanocortin receptor activation. While acute side effects (nausea, flushing) are manageable and typically transient, the primary long-term concern is the effect on melanocytes — particularly new or changing moles. Dermatological monitoring is essential for all users. MT-II is NOT FDA-approved and long-term human safety data is limited.

Common Side Effects

Dose-dependent and generally transient:

Nausea — nearly universal at initiation. Caused by central MC3R/MC4R activation. Dose-dependent, peaks in the first 2–3 days, and typically resolves within 3–7 days as tolerance develops.
Facial flushing — very common. Warmth and redness in the face, typically 15–45 minutes post-injection, lasting 1–2 hours. Caused by MC1R effects on vasculature.
Appetite suppression — common. MC4R-mediated reduction in hunger. Most pronounced during loading phase.
Spontaneous erections (men) — common, especially during loading. Caused by MC3R/MC4R activation. Can occur hours after injection.
Increased libido — common in both men and women. MC3R/MC4R hypothalamic activation.
Injection site reactions — mild redness, itching, or localized darkening at injection site.
Fatigue and yawning — some users report sleepiness post-injection, which complements the before-bed injection strategy.

Less common but clinically significant:

New nevi (moles) — MT-II can cause new moles to appear. Any new mole requires dermatological evaluation.
Darkening or enlargement of existing moles — existing nevi may darken, enlarge, or change shape. Must be monitored by a dermatologist.
Freckle darkening — pre-existing freckles frequently darken more quickly than surrounding skin, especially in fair-skinned individuals.
Blood pressure changes — mild transient increases have been reported; relevant for those with pre-existing hypertension.
Headache — occasional, usually in the first few days of use.

Mole Monitoring — Critical Safety Requirement

This is the most important safety section in this guide. Melanotan II stimulates melanocyte activity broadly. This includes melanocytes within existing moles and the potential activation of dormant melanocytes. New or changing moles are the primary long-term safety concern with MT-II use.

Mandatory Monitoring Protocol:

Baseline skin exam before starting MT-II — Photograph all existing moles before your first injection. Use a dermatoscope app or visit a dermatologist for a baseline full-body skin exam. This provides a reference for detecting any changes.
Monthly self-exams during use — Check all moles monthly using the ABCDE criteria: Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolving (any change in size, shape, or color). Compare to your baseline photographs.
Annual dermatological screening — All MT-II users should have an annual professional skin exam by a dermatologist. Inform your dermatologist that you use Melanotan II so they can provide appropriate monitoring.
Immediate evaluation of any changes — Any new mole, or any change in an existing mole (darkening, enlargement, border irregularity, itching, bleeding), warrants immediate dermatological evaluation. Do not wait for your scheduled annual exam.

Contraindications

History of melanoma or atypical moles (dysplastic nevi) — absolute contraindication. Stimulating melanocyte activity in individuals predisposed to melanocyte malignancy is an unacceptable risk.
Family history of melanoma — strong contraindication. First-degree relatives with melanoma significantly elevates your personal risk.
Pregnancy and breastfeeding — no safety data exists. Avoid entirely. Melanocortin receptors are expressed in fetal tissue.
Active skin cancer of any type — MT-II should not be used with any active cutaneous malignancy.
Addison's disease or adrenal insufficiency — melanocortin signaling is involved in adrenal function; MT-II could complicate existing adrenal conditions.
Uncontrolled hypertension — MT-II can cause transient blood pressure elevation. Monitor carefully if used with pre-existing hypertension.
Autoimmune conditions affecting the skin — conditions like vitiligo, lupus, or dermatomyositis may be unpredictably affected by melanocyte stimulation.

When to Stop or Reduce Dose

Any new mole or change in an existing mole — stop immediately and consult a dermatologist
Severe or persistent nausea that does not improve after 10–14 days at the lowest dose (0.25 mg)
Significant uneven darkening or hyperpigmentation that concerns you
Persistent blood pressure elevation above your baseline
Severe headaches that do not resolve within the first week
Any symptom that feels unusual or concerning — err on the side of caution

Regulatory Status: Melanotan II is NOT FDA-approved for any indication. It is classified as a research peptide. Melanotan I (afamelanotide/Scenesse) IS FDA-approved for erythropoietic protoporphyria (EPP) but is a different peptide. PT-141 (bremelanotide/Vyleesi), a derivative of MT-II, IS FDA-approved for HSDD in premenopausal women. MT-II is prohibited by WADA (World Anti-Doping Agency). Regulations vary by jurisdiction — verify your local laws before purchasing.

Common Melanotan II Dosing Mistakes

Avoid these common errors to get the most out of your Melanotan II protocol:

Starting at too high a dose

The single most common mistake. Starting at 0.5 mg or higher virtually guarantees significant nausea, facial flushing, and discomfort. Always start at 0.25 mg to assess tolerance. The loading phase is not a race — you will achieve the same result whether you start at 0.25 mg or 0.5 mg; the lower dose simply involves less suffering.

Injecting in the morning or before meals

MT-II commonly causes nausea lasting 30–90 minutes. Injecting before bed allows you to sleep through the worst of it. Injecting in the morning or before meals amplifies nausea and can ruin your appetite for the day. Evening injection before bed is the gold standard timing.

Skipping UV exposure entirely

MT-II enhances melanogenesis but does not replace the UV stimulus entirely. Some UV exposure — even brief (10–20 minutes of natural sun or a low-intensity tanning session) — is needed to trigger melanocyte activation and melanin distribution. Without any UV, results will be significantly slower and less uniform.

Excessive UV exposure during loading

The opposite extreme is also a mistake. MT-II dramatically sensitizes your skin to UV, meaning you need far LESS sun exposure than normal. Spending hours in the sun or using high-intensity tanning beds while on MT-II dramatically increases your risk of sunburn and long-term UV damage. Brief, controlled UV exposure is the goal.

Ignoring new or changing moles

MT-II activates melanocytes broadly, which can cause new nevi to appear and existing moles to change. Any new mole, or any change in size, shape, color, or border of an existing mole, must be evaluated by a dermatologist. This is not optional. Failing to monitor moles is the most serious safety error with this peptide.

Using MT-II with a history of melanoma or atypical moles

MT-II is absolutely contraindicated in anyone with a personal or family history of melanoma or dysplastic nevi syndrome. Stimulating melanocyte activity in individuals predisposed to melanocyte malignancy is an unacceptable risk. No cosmetic benefit justifies this.

Not rotating injection sites

Repeated subcutaneous injection at the same site can cause localized darkening (hyperpigmentation) at the injection area, as well as lipodystrophy over time. Rotate between abdomen, thigh, and upper arm. This ensures even melanin distribution and reduces injection site complications.

Storing reconstituted MT-II at room temperature

Reconstituted MT-II must be stored in the refrigerator (2–8°C). At room temperature, the peptide degrades rapidly, losing potency within days. Properly refrigerated, reconstituted MT-II is stable for approximately 4–6 weeks. Never freeze reconstituted peptide. Unreconstituted (lyophilized) powder can be stored in the freezer for extended periods.

Expecting uniform tanning without patience

MT-II tanning is not uniform from day one. Some areas of the body (face, arms, shoulders) darken faster than others. Freckles may darken more quickly than surrounding skin initially. This unevenness typically resolves over the course of the loading phase as melanin production equilibrates. Allow 3–4 weeks of loading before judging the final result.

Frequently Asked Questions

Key Takeaways

Melanotan II is a non-selective melanocortin agonist — activating MC1R through MC5R for tanning, sexual function, and appetite suppression
Loading phase: 0.25–0.5 mg SubQ daily for 2–4 weeks — always start at 0.25 mg to manage nausea
Maintenance phase: 0.5–1 mg, 1–2x per week — sustains tan with minimal dosing and occasional UV exposure
Nausea is nearly universal at initiation — inject before bed, start low, and allow 3–7 days for tolerance to develop
Some UV exposure is required — but dramatically less than normal tanning. Brief sessions of 10–20 minutes are sufficient
Mole monitoring is mandatory — baseline skin exam, monthly self-checks, and annual dermatological screening. Stop immediately for any new or changing moles.
Absolutely contraindicated with melanoma history, atypical moles, or family history of melanoma
MT-II is NOT Melanotan I — Melanotan I (Scenesse) is MC1R-selective and FDA-approved for EPP. MT-II is non-selective and not approved for any indication.
For sexual function specifically, consider PT-141 (bremelanotide/Vyleesi) — MC4R-optimized and FDA-approved for HSDD
Not FDA-approved — classified as a research peptide. Banned by WADA for competitive athletes. Check local regulations.

This article is for educational and informational purposes only. Melanotan II (MT-II) is not approved by the FDA for human use and is classified as a research peptide. It is not intended to diagnose, treat, cure, or prevent any disease. Melanotan II can cause new or changing moles — dermatological monitoring is essential. It is absolutely contraindicated in individuals with a history of melanoma or dysplastic nevi. Consult a qualified healthcare provider before using any research peptide, especially if you have pre-existing medical conditions, are taking medications, or are pregnant or nursing. See our Medical Disclaimer.

References

Dorr RT, et al. “Effects of a superpotent melanotropic peptide in combination with solar UV radiation on tanning of the skin in human volunteers.” Arch Dermatol. 2004;140(7):827-835. PubMed
Hadley ME, Dorr RT. “Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization.” Peptides. 2006;27(4):921-930. PubMed
Wessells H, et al. “Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction: double-blind, placebo controlled crossover study.” J Urol. 1998;160(2):389-393. PubMed
Hruby VJ, et al. “Cyclic lactam alpha-melanotropin analogues of Ac-Nle4-cyclo[Asp5,D-Phe7,Lys10] alpha-melanocyte-stimulating hormone-(4-10)-NH2 with bulky aromatic amino acids at position 7 show high antagonist potency and selectivity at specific melanocortin receptors.” J Med Chem. 1995;38(18):3454-3461. PubMed
Langan EA, et al. “Melanotropic peptides: more than just 'Barbie drugs' and 'sun-tan jabs'?” Br J Dermatol. 2010;163(3):451-455. PubMed
Facchinetti F, et al. “Alpha-MSH and synthetic melanotropins: who does what?” Curr Med Chem. 2002;9(10):1023-1028.
Ugwu SO, et al. “Skin pigmentation and pharmacokinetics of melanotan-II in humans.” Int J Pharm. 1997;147(2):159-168.
Clayton AH, et al. “Bremelanotide for female sexual dysfunctions in premenopausal women: a randomized, placebo-controlled dose-finding trial.” Womens Health (Lond). 2016;12(3):325-337. PubMed
Brennan R, et al. “Melanotan II as a lifestyle drug: a preliminary investigation of users.” J Subst Use. 2014;19(1-2):52-56.
Nelson ME, et al. “Peptide hormones and sport: misuse and effect on performance.” Br J Sports Med. 2012;46(4):228-231.

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PT-141 Dosage Guide

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