Updated February 2026

Melanotan II Dosing Protocol

Comprehensive Melanotan II protocol reference covering loading and maintenance schedules, reconstitution precision, multi-receptor melanocortin effects, and current evidence boundaries.

Half-life

~1-2 hours plasma; effects persist longer

Dose range

250 mcg to 1 mg per injection

Status

Not FDA-approved

Class

Non-selective melanocortin agonist

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Quick Reference Card

Peptide Name

Melanotan II

Aliases

MT-II; MT-2; MT2; Melanotan 2; Barbie Drug

Category / Class

Non-Selective Melanocortin Receptor Agonist

Half-Life

~1-2 hours plasma; pharmacodynamic effects can persist 24-48+ hours

Dosing Frequency

Daily loading phase, then 1-2x weekly maintenance

Dose Range

250 mcg to 1 mg per injection

Common Vial Sizes

10mg

Route of Administration

Subcutaneous (SubQ); intranasal has also been studied

Regulatory Status

Not FDA-approved for any indication. Illegal to sell for human use in the US, UK, and Australia; unregulated research compound.

Developer

University of Arizona (Hruby, Hadley, Dorr et al., 1980s-1990s)

Key Stat

Placebo-controlled ED studies reported erection outcomes in 17 of 20 men and increased sexual desire in 68% vs 19% with placebo.

Peptide Name	Melanotan II
Aliases	MT-II; MT-2; MT2; Melanotan 2; Barbie Drug
Category / Class	Non-Selective Melanocortin Receptor Agonist
Half-Life	~1-2 hours plasma; pharmacodynamic effects can persist 24-48+ hours
Dosing Frequency	Daily loading phase, then 1-2x weekly maintenance
Dose Range	250 mcg to 1 mg per injection
Common Vial Sizes	10mg
Route of Administration	Subcutaneous (SubQ); intranasal has also been studied
Regulatory Status	Not FDA-approved for any indication. Illegal to sell for human use in the US, UK, and Australia; unregulated research compound.
Developer	University of Arizona (Hruby, Hadley, Dorr et al., 1980s-1990s)
Key Stat	Placebo-controlled ED studies reported erection outcomes in 17 of 20 men and increased sexual desire in 68% vs 19% with placebo.

What Is Melanotan II?

Melanotan II (MT-II) is a synthetic cyclic heptapeptide analog of alpha-melanocyte-stimulating hormone that was developed as a sunless tanning candidate and later studied for sexual-function effects. It was designed with structural changes that improve stability and receptor potency relative to endogenous alpha-MSH.

Its core melanocortin pharmacophore drives non-selective receptor agonism across MC1R, MC3R, MC4R, and MC5R. This broad receptor profile explains its mixed phenotype: tanning effects, appetite changes, and central sexual-arousal signaling.

Unlike receptor-selective descendants, MT-II remained a broad-activity research compound. Clinical studies in the 1990s and early 2000s explored both tanning and erectile-dysfunction endpoints, and those findings helped seed development of bremelanotide (PT-141), which later became FDA-approved for female HSDD.

Melanotan II itself has never received FDA approval and remains an unregulated research compound. This page is educational and research-reference only.

How Melanotan II Works: Multi-Receptor Melanocortin Agonism

MT-II acts as a non-selective melanocortin agonist, with clinically noticeable effects tied mainly to MC1R and MC3R/MC4R signaling.

MC1R and Melanogenesis

MC1R activation in melanocytes increases cAMP signaling and tyrosinase activity, driving eumelanin production and visible pigmentation changes.

MC3R and MC4R Sexual Signaling

Central melanocortin signaling in hypothalamic and related pathways can influence arousal and erectile-response patterns independent of PDE5 pathways.

MC4R Appetite Effects

Appetite suppression is commonly reported and aligns with melanocortin-system satiety signaling.

MC5R Secondary Effects

MC5R signaling in exocrine tissues may contribute to secondary response patterns, though it is generally less dominant than MC1R and MC3R/MC4R effects.

Non-Selective Profile and Side Effects

Broad receptor activity contributes to mixed outcomes: target effects plus nausea, flushing, and other dose-limiting adverse effects in sensitive users.

This multi-receptor profile differentiates MT-II from more selective compounds such as afamelanotide (MC1R-biased) and bremelanotide (MC3R/MC4R-focused).

Melanotan II Dosing Protocol and Titration Schedule

Assessment

Days 1-3

100-250 mcg daily

Tolerance check; bedtime dosing is often used to reduce nausea burden.

Loading (low)

Days 4-14

250-500 mcg daily

Escalate based on nausea and flushing tolerance.

Loading (standard)

Weeks 3-6

500-1000 mcg daily

Continue until target pigmentation is achieved; UV exposure is commonly coordinated.

Maintenance

Ongoing

500-1000 mcg, 1-2x weekly

Used to maintain pigmentation after loading phase.

ED trial dose context

As needed

0.025 mg/kg (~1.75 mg at 70 kg)

Clinical-study dose associated with higher nausea burden than typical tanning protocols.

Community low-dose sexual-function context

As needed

500 mcg to 1 mg

Community-reported range used to reduce GI burden relative to trial-level dosing.

Phase	Weeks	Weekly Dose	Notes
Assessment	Days 1-3	100-250 mcg daily	Tolerance check; bedtime dosing is often used to reduce nausea burden.
Loading (low)	Days 4-14	250-500 mcg daily	Escalate based on nausea and flushing tolerance.
Loading (standard)	Weeks 3-6	500-1000 mcg daily	Continue until target pigmentation is achieved; UV exposure is commonly coordinated.
Maintenance	Ongoing	500-1000 mcg, 1-2x weekly	Used to maintain pigmentation after loading phase.
ED trial dose context	As needed	0.025 mg/kg (~1.75 mg at 70 kg)	Clinical-study dose associated with higher nausea burden than typical tanning protocols.
Community low-dose sexual-function context	As needed	500 mcg to 1 mg	Community-reported range used to reduce GI burden relative to trial-level dosing.

Evidence Level Notice and Dosing Notes

Evidence level: There is no FDA-approved MT-II dose schedule. Current loading and maintenance models are community-derived and informed by early phase studies.

Titration rationale: Nausea is the primary dose-limiting side effect. Gradual escalation often improves tolerability over the first several doses.

Timing: Bedtime administration is commonly used to reduce perceived impact of transient nausea and flushing.

UV coordination: Pigment development is often paired with brief UV exposure windows in community workflows.

Missed dose: Missed loading doses usually have limited immediate impact because visible tanning reflects cumulative melanin deposition.

Fitzpatrick context: Fairer skin phenotypes often show faster visible changes at lower dose bands, while darker baseline phenotypes can require longer timelines.

Cycle length: Community loading windows often run 4-8 weeks, but long-term controlled safety data is limited.

Melanotan II Reconstitution Guide

Vial Size: 10 mg

BAC Water: 1.0 mL

Concentration: 10 mg/mL

250 mcg: 0.025 mL (2.5 units)

500 mcg: 0.05 mL (5 units)

750 mcg: 0.075 mL (7.5 units)

1 mg: 0.10 mL (10 units)

Vial Size: 10 mg

BAC Water: 2.0 mL

Concentration: 5 mg/mL

250 mcg: 0.05 mL (5 units)

500 mcg: 0.10 mL (10 units)

750 mcg: 0.15 mL (15 units)

1 mg: 0.20 mL (20 units)

Vial Size: 10 mg

BAC Water: 3.0 mL

Concentration: 3.33 mg/mL

250 mcg: 0.075 mL (7.5 units)

500 mcg: 0.15 mL (15 units)

750 mcg: 0.225 mL (22.5 units)

1 mg: 0.30 mL (30 units)

Vial Size: 10 mg

BAC Water: 5.0 mL

Concentration: 2 mg/mL

250 mcg: 0.125 mL (12.5 units)

500 mcg: 0.25 mL (25 units)

750 mcg: 0.375 mL (37.5 units)

1 mg: 0.50 mL (50 units)

Vial Size	BAC Water Added	Concentration	250 mcg Dose	500 mcg Dose	750 mcg Dose	1 mg Dose
10 mg	1.0 mL	10 mg/mL	0.025 mL (2.5 units)	0.05 mL (5 units)	0.075 mL (7.5 units)	0.10 mL (10 units)
10 mg	2.0 mL	5 mg/mL	0.05 mL (5 units)	0.10 mL (10 units)	0.15 mL (15 units)	0.20 mL (20 units)
10 mg	3.0 mL	3.33 mg/mL	0.075 mL (7.5 units)	0.15 mL (15 units)	0.225 mL (22.5 units)	0.30 mL (30 units)
10 mg	5.0 mL	2 mg/mL	0.125 mL (12.5 units)	0.25 mL (25 units)	0.375 mL (37.5 units)	0.50 mL (50 units)

Step-by-Step Reconstitution Instructions

Step-by-step vial preparation visual for peptide reconstitution.

Sanitize MT-II and BAC water vial stoppers with alcohol.
Draw planned BAC water volume into a sterile syringe.
Inject slowly against vial wall rather than directly onto powder.
Allow dissolution and gently swirl; avoid vigorous shaking.
Verify clear, colorless solution before use.
Label concentration and date of reconstitution.
Store refrigerated at 2-8C after mixing.

Need exact syringe units for a custom vial size or BAC water volume? Use the free Peptide Reconstitution Calculator.Open Calculator

Melanotan II Side Effects and Safety

Side effects are dose-dependent and commonly include nausea and flushing. Long-term safety remains uncertain in unregulated-use settings.

Common effects: Nausea, flushing, appetite suppression, fatigue, and yawning are frequently reported during initiation and dose escalation; severe nausea was reported in ED-dose trial contexts.

Sexual effects: Spontaneous erections and increased sexual desire can occur through central melanocortin signaling pathways.

Dermatologic concerns: Darkening of nevi/freckles and other pigment changes are reported. Dermatology monitoring is prudent in higher-risk users.

Serious events: Case reports include priapism and toxicity events at large dosing errors, including rhabdomyolysis in overdose contexts.

Contraindication context: Risk-benefit concerns are elevated in individuals with melanoma history, uncontrolled cardiovascular disease, or priapism predisposition.

Melanotan II Clinical Trial and Research Results

Dorr et al. 1996

Phase I • 2 weeks

Healthy male volunteers

Increased pigmentation with frequent nausea and spontaneous erection events at studied dose ranges.

Wessells et al. 1998

Phase II • Acute dosing

Psychogenic ED cohort

Placebo-controlled findings showed strong erection-response signals in most treated participants.

Wessells et al. 2000 (Urology)

Phase II • Acute dosing

Organic ED cohort

Observed erectile-response and rigidity-time improvements compared with placebo.

Wessells et al. 2000 (combined)

Combined analysis • Acute dosing

Mixed ED populations

Reported increases in sexual-desire outcomes and robust erection frequency with notable nausea rates.

Dorr et al. 2004

Phase I • 2 weeks

Healthy volunteers with UV exposure

MT-II plus UV showed stronger pigmentation outcomes than UV-only comparators.

Minakova et al. 2019

Preclinical • 7-14 days

Maternal immune activation mouse model

Reported social-behavior improvements with proposed MC4R-oxytocin pathway involvement.

Trial	Phase	Duration	Population	Key Result
Dorr et al. 1996	Phase I	2 weeks	Healthy male volunteers	Increased pigmentation with frequent nausea and spontaneous erection events at studied dose ranges.
Wessells et al. 1998	Phase II	Acute dosing	Psychogenic ED cohort	Placebo-controlled findings showed strong erection-response signals in most treated participants.
Wessells et al. 2000 (Urology)	Phase II	Acute dosing	Organic ED cohort	Observed erectile-response and rigidity-time improvements compared with placebo.
Wessells et al. 2000 (combined)	Combined analysis	Acute dosing	Mixed ED populations	Reported increases in sexual-desire outcomes and robust erection frequency with notable nausea rates.
Dorr et al. 2004	Phase I	2 weeks	Healthy volunteers with UV exposure	MT-II plus UV showed stronger pigmentation outcomes than UV-only comparators.
Minakova et al. 2019	Preclinical	7-14 days	Maternal immune activation mouse model	Reported social-behavior improvements with proposed MC4R-oxytocin pathway involvement.

MT-II development did not progress to large modern phase programs, but early human studies established its multi-effect profile. Regulatory pathways later advanced receptor-targeted descendants such as bremelanotide rather than native MT-II.

Storage and Handling

Lyophilized (powder)

-20C

Long-term (years)

Lyophilized (powder)

2-8C

Several months

Lyophilized (powder)

Room temperature

Shipping tolerance (weeks)

Reconstituted

2-8C

2-4 weeks

Reconstituted aliquots

-20C

3-4 months

State	Temperature	Duration
Lyophilized (powder)	-20C	Long-term (years)
Lyophilized (powder)	2-8C	Several months
Lyophilized (powder)	Room temperature	Shipping tolerance (weeks)
Reconstituted	2-8C	2-4 weeks
Reconstituted aliquots	-20C	3-4 months

Protect from light, use BAC water for multi-dose handling, and minimize freeze-thaw cycles via single-use aliquoting when freezing.

Melanotan II vs Afamelanotide vs PT-141

Structure

Melanotan II: Cyclic heptapeptide (7 AA)

Afamelanotide (MT-I): Linear tridecapeptide (13 AA)

PT-141 (Bremelanotide): Cyclic heptapeptide derivative (active metabolite lineage)

Receptor Selectivity

Melanotan II: Non-selective MC1R/3R/4R/5R

Afamelanotide (MT-I): MC1R-preferring

PT-141 (Bremelanotide): MC3R/MC4R-preferring

Plasma Half-Life

Melanotan II: ~1-2 hours

Afamelanotide (MT-I): ~0.8-1.7 hours

PT-141 (Bremelanotide): ~2.7 hours

Primary Effect

Melanotan II: Tanning + sexual + appetite effects

Afamelanotide (MT-I): Tanning and photoprotection

PT-141 (Bremelanotide): Sexual arousal/desire

Tanning Effect

Melanotan II: Strong

Afamelanotide (MT-I): Strong

PT-141 (Bremelanotide): Minimal

Sexual Function Effect

Melanotan II: Strong signal in ED studies

Afamelanotide (MT-I): Not primary

PT-141 (Bremelanotide): Primary use-case

Dosing Frequency

Melanotan II: Daily loading, then 1-2x weekly

Afamelanotide (MT-I): Implant interval strategy

PT-141 (Bremelanotide): On-demand, max 1 dose per 24 hours

Route

Melanotan II: SubQ; intranasal studied

Afamelanotide (MT-I): SubQ implant

PT-141 (Bremelanotide): SubQ injection

FDA Status

Melanotan II: Not approved

Afamelanotide (MT-I): Approved for EPP (Scenesse)

PT-141 (Bremelanotide): Approved for female HSDD (Vyleesi)

Nausea Burden

Melanotan II: High and dose-limiting

Afamelanotide (MT-I): Lower in selective context

PT-141 (Bremelanotide): Common in labeling

Unique Advantage

Melanotan II: Broad multi-effect profile

Afamelanotide (MT-I): Most targeted tanning pathway

PT-141 (Bremelanotide): Regulated on-demand sexual function indication

Feature	Melanotan II	Afamelanotide (MT-I)	PT-141 (Bremelanotide)
Structure	Cyclic heptapeptide (7 AA)	Linear tridecapeptide (13 AA)	Cyclic heptapeptide derivative (active metabolite lineage)
Receptor Selectivity	Non-selective MC1R/3R/4R/5R	MC1R-preferring	MC3R/MC4R-preferring
Plasma Half-Life	~1-2 hours	~0.8-1.7 hours	~2.7 hours
Primary Effect	Tanning + sexual + appetite effects	Tanning and photoprotection	Sexual arousal/desire
Tanning Effect	Strong	Strong	Minimal
Sexual Function Effect	Strong signal in ED studies	Not primary	Primary use-case
Dosing Frequency	Daily loading, then 1-2x weekly	Implant interval strategy	On-demand, max 1 dose per 24 hours
Route	SubQ; intranasal studied	SubQ implant	SubQ injection
FDA Status	Not approved	Approved for EPP (Scenesse)	Approved for female HSDD (Vyleesi)
Nausea Burden	High and dose-limiting	Lower in selective context	Common in labeling
Unique Advantage	Broad multi-effect profile	Most targeted tanning pathway	Regulated on-demand sexual function indication

These compounds share melanocortin ancestry but are not interchangeable due to receptor selectivity and clinical purpose differences.

MT-II has the broadest mixed-effect profile but also the broadest side-effect burden.

Afamelanotide and PT-141 advanced to regulated indications where MT-II did not.

See the PT-141 Protocol and Afamelanotide Protocol for compound-specific guides.

Melanotan II Stacking Protocols

Stack 1

Tanning and Photoprotection Stack

MT-II is sometimes paired with antioxidant-support workflows (for example glutathione strategies) to layer pigment and oxidative-stress considerations.

View protocol

Stack 2

Sexual Function Alternation

Some users alternate MT-II loading frameworks with PT-141 on-demand use to separate pigmentation and sexual-function goals.

See the compound-specific See PT-141 protocol for additional context.

View protocol

Stack 3

Body-Composition Support

Appetite-related MT-II effects are sometimes paired with GH-secretagogue frameworks in community body-composition protocols.

See the compound-specific See CJC-1295 no DAC protocol for additional context.

View protocol

Frequently Asked Questions - Melanotan II

Q1: What is the starting dose of Melanotan II?

Many users start between 100 and 250 mcg daily to assess nausea/flushing tolerance before moving toward common loading doses around 500 mcg.

Q2: What is Melanotan II's half-life?

Plasma half-life is commonly described around 1-2 hours, while visible pigmentation and other pharmacodynamic effects can persist much longer. The frequently repeated 33-hour claim is generally treated as pharmacodynamic duration confusion rather than plasma half-life.

Q3: What results can be expected for tanning?

Visible changes are often reported within 1-2 weeks during loading, with fuller tanning outcomes developing over 4-8 weeks depending on skin type and UV coordination.

Q4: How do you reconstitute Melanotan II?

A common setup is 10 mg with 2 mL BAC water (5 mg/mL), where a 500 mcg dose equals 0.10 mL or 10 units on a U-100 syringe.

Q5: Is Melanotan II FDA-approved?

No. Melanotan II is not approved by FDA, EMA, MHRA, or TGA for any indication and remains an unregulated research compound.

Q6: What are the most common side effects?

Nausea and flushing are most common, followed by appetite changes, fatigue, and yawning. Side effects are generally dose-dependent.

Q7: How does Melanotan II compare to PT-141 and afamelanotide?

MT-II is non-selective and broader-acting, while afamelanotide is more tanning-focused and PT-141 is more sexual-function-focused in regulated settings.

Q8: Melanotan II nasal spray vs injection: what is the difference?

SubQ injection is the dominant protocol format in published and community dosing workflows, while intranasal use appears in limited contexts and is generally considered less predictable for dose equivalence.

Q9: What vial size is most common?

10 mg lyophilized vials are the most common market format.

Q10: How much BAC water should I add to a 10 mg vial?

2 mL is commonly used for practical unit math at 500 mcg dosing, though 1 mL, 3 mL, and 5 mL setups are also used depending on preferred draw volume.

Q11: What is the highest dose studied?

Early clinical study ranges reached roughly 0.03 mg/kg, while overdose case reports describe severe toxicity at much higher accidental/self-administered levels.

Q12: How should reconstituted Melanotan II be stored?

Store at 2-8C and protect from light. For longer windows, single-use aliquot freezing is used to reduce freeze-thaw damage.

Q13: Why did MT-II development stop while PT-141 and afamelanotide advanced?

Development emphasis shifted toward receptor-selective descendants with clearer indication pathways and regulatory strategy fit.

Sources & Research

Dorr RT, Lines R, Levine N, et al. "Evaluation of Melanotan-II, a superpotent cyclic melanotropic peptide in a pilot phase-I clinical study." Life Sciences, 1996 PubMed.
Wessells H, Fuciarelli K, Hansen J, et al. "Synthetic melanotropic peptide initiates erections in men with psychogenic erectile dysfunction." Journal of Urology, 1998 PubMed.
Wessells H, Gralnek D, Dorr R, et al. "Effect of an alpha-melanocyte stimulating hormone analog on penile erection and sexual desire in men with organic erectile dysfunction." Urology, 2000 PubMed.
Wessells H, Levine N, Hadley ME, et al. "Melanocortin receptor agonists, penile erection, and sexual motivation: human studies with Melanotan II." International Journal of Impotence Research, 2000 PubMed.
Dorr RT, Ertl GA, Levine N, et al. "Effects of a superpotent melanotropic peptide in combination with solar UV radiation on tanning of the skin in human volunteers." Archives of Dermatology, 2004.
Nelson ME, Bryant SM, Aks SE. "Melanotan II injection resulting in systemic toxicity and rhabdomyolysis." Clinical Toxicology, 2012 PubMed.
Hjuler KF, Lorentzen HF. "Melanoma associated with the use of melanotan-II." Dermatology, 2014 PubMed.
Schulze F, Erdmann H, Hardkop LH, et al. "Eruptive naevi and darkening of pre-existing naevi 24 h after a single mono-dose injection of melanotan II." European Journal of Dermatology, 2014 PubMed.
Mallory CW, Lopategui DM, Cordon BH. "Melanotan tanning injection: a rare cause of priapism." Sexual Medicine, 2021 Link.
Habbema L, Halk AB, Neumann M, Bergman W. "Risks of unregulated use of alpha-melanocyte-stimulating hormone analogues." International Journal of Dermatology, 2017 PubMed.
Minakova E, Lang J, Medel-Matus JS, et al. "Melanotan-II reverses autistic features in a maternal immune activation mouse model of autism." Translational Psychiatry, 2019 Link.
Hadley ME, Dorr RT. "Melanocortin peptide therapeutics: historical milestones, clinical studies and commercialization." Peptides, 2006 PubMed.
Wikipedia: Melanotan II. Link.

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Disclaimer

The information on this page is for educational and research reference purposes only. Melanotan II is not approved by FDA, EMA, MHRA, or TGA for any indication and is illegal to sell for human use in the US, UK, and Australia. No compounds discussed on this site are intended for human consumption. This is not medical advice.

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