Side-by-side · Research reference

Melanotan-IIvsSemaglutide

Side-by-side comparison across mechanism, dosage, evidence, side effects, administration, and stack synergies. Citations on every claim where available.

APhase 1Reviewed9/43 cited

BFDA-ApprovedVerified15/53 cited

Melanotan-II

MC1R + MC4R agonist · Tanning + sexual response

0.25–1.0 mgPer doseDorr 1996

Phase 1Evidence levelDorr 1996

~1 hrHalf-life

SQ · Abdomen · Loading 5–7 days, then maintenance

Semaglutide

GLP-1 RA · FDA-Approved

0.25–2.4 mgWeekly doseWEGOVY (semaglutide) injection 2021

14.9%Body-weight ↓Wilding 2021

~7 daysHalf-lifeWEGOVY (semaglutide) injection 2021

SQ · Abdomen / thigh / arm · Once weekly

01Mechanism of Action

Parameter

Melanotan-II

Semaglutide

Primary target

MC1R (skin) + MC3R + MC4R (CNS sexual / appetite)Dorr 1996

GLP-1 receptor (GLP-1R)WEGOVY (semaglutide) injection 2021

Pathway

MC1R agonism → melanocyte tyrosinase → eumelanin synthesis. MC4R → autonomic sexual arousal centresDorr 1996 Simerly 2023

GLP-1R agonism → ↑glucose-dependent insulin secretion, ↓glucagon, ↓gastric emptying, ↓appetite via hypothalamic centresWilding 2021

Downstream effect

Skin darkening, photo-protection, increased sexual desire / spontaneous erectionDorr 1996

Improved glycemic control, reduced caloric intake, body-weight reduction, cardiovascular risk reductionWilding 2021

Feedback intact?

—

Glucose-dependent insulin release preserves physiological feedback

Origin

Cyclic 7-AA modified α-MSH analog; designed at University of ArizonaDorr 1996

Modified GLP-1(7-37) with two amino-acid substitutions and C-18 fatty-acid acylation for albumin binding and 168-h half-lifeWEGOVY (semaglutide) injection 2021

Antibody development

—

02Dosage Protocols

Parameter

Melanotan-II

Semaglutide

Loading phase

0.25–0.5 mg/day SQ × 5–7 daysDorr 1996

Builds up to visible tan.

—

Maintenance

0.5–1.0 mg 1–2×/week

After visible tan develops; supports with UV exposure.

—

Frequency

Daily during loading; 1–2× per week maintenance

Once weekly, same day each week

Lower / starter dose

0.1 mg / day

Conservative starter — assess tolerability for nausea.

—

Evidence basis

Phase 1 + anecdotalDorr 1996

FDA-approved · Phase 3 RCTsWilding 2021 WEGOVY (semaglutide) injection 2021

Duration

8–12 weeks per cycle

Indefinite for chronic indication

Discontinuation results in weight regain.

Reconstitution

Bacteriostatic water; protect from light

Pre-mixed pen device (commercial). Research lyophilised vial: bacteriostatic water per label.

Timing

Evening preferred (24h tan-development cycle)

Any time of day, with or without food

Half-life

~1 hour plasma; effects on melanocytes persist days

~7 days (168 h)WEGOVY (semaglutide) injection 2021

Standard dose (T2D, Ozempic)

—

0.5–1.0 mg / weekWEGOVY (semaglutide) injection 2021

Standard dose (weight, Wegovy)

—

2.4 mg / week (after 16-wk titration)WEGOVY (semaglutide) injection 2021 Wilding 2021

Titration schedule

—

0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg over 16 weeks

Mitigates GI side effects.

04Side Effects & Safety

Parameter

Melanotan-II

Semaglutide

Nausea

Common, especially loading phase

—

Flushing

Common transient

—

Spontaneous erection

Common in men — MC4R cross-effectDorr 1996

—

Increased mole / freckle pigmentation

Existing moles darken; new lesions possible

—

Melanoma risk

Theoretical concern — increased melanocyte activity; CAUTION in melanoma history

—

Appetite suppression

MC4R-mediated; mild

—

Pregnancy / OB

Contraindicated

ContraindicatedWEGOVY (semaglutide) injection 2021

GI symptoms

—

Nausea, vomiting, diarrhea, constipation (very common)Wilding 2021

Injection site reaction

—

Mild erythema, pruritus

Pancreatitis risk

—

Rare; discontinue if suspectedWEGOVY (semaglutide) injection 2021

Thyroid C-cell tumours

—

Boxed warning — contraindicated in MEN2 / personal or family MTC historyWEGOVY (semaglutide) injection 2021

Hypoglycemia

—

Low risk as monotherapy; elevated when combined with sulfonylureas / insulin

Gallbladder events

—

Increased cholelithiasis

Heart rate

—

Modest ↑ resting HR (~2-4 bpm)

Absolute Contraindications

Melanotan-II

·History of melanoma or atypical mole syndrome
·Pregnancy / breastfeeding
·Active uncontrolled hypertension

Semaglutide

·Personal or family history of medullary thyroid carcinoma
·Multiple endocrine neoplasia syndrome type 2
·Pregnancy / breastfeeding
·Hypersensitivity to semaglutide

Relative Contraindications

Melanotan-II

·Significant freckling / dysplastic nevus
·Personal or family melanoma history

Semaglutide

·Severe gastroparesis
·History of pancreatitis
·Diabetic retinopathy (may worsen with rapid glycemic improvement)

05Administration Protocol

Parameter

Melanotan-II

Semaglutide

1. Reconstitution

Add 2 mL bacteriostatic water to 10 mg vial → 5 mg/mL = 500 mcg per 0.1 mL. Light-protected.

Commercial: pre-filled pen, no reconstitution. Research vial: per-label or bacteriostatic water.

2. Injection site

SQ — abdomen. Rotate sites.

SQ — abdomen, thigh, or upper arm. Rotate sites weekly to avoid lipohypertrophy.

3. Timing

Evening preferred. UV exposure (sunlight or tanning bed) helps develop tan.

Once weekly, same day. Day can be changed if ≥2 days separate doses.

4. Storage

Lyophilised: refrigerate, light-protected. Reconstituted: refrigerate ≤30 days.

Pen: refrigerate 2–8 °C unopened; room temp ≤30 °C up to 56 days after first use.

5. Needle

29–31G insulin syringe.

Pen-supplied 31–34G needle. Research vial: 27–31G insulin syringe.

06Stack Synergy

Melanotan-II

— no documented stacks

Semaglutide

+ Tirzepatide

Weak

View Tirzepatide →

Combining two GLP-1 RA-class drugs is not clinically validated and risks additive GI toxicity. Tirzepatide's GIP component already provides complementary mechanism vs pure GLP-1; stacking with semaglutide adds receptor saturation but no synergy. NOT recommended.

Note: Stack not recommended — choose one GLP-1 RA
Primary benefit: (none — additive toxicity, no synergy)