Side-by-side · Research reference

GLP-1 (7-37)vsMelanotan-II

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

AHuman-MechanisticHUMAN-REVIEWED16/43 cited

BPhase 1HUMAN-REVIEWED9/43 cited

GLP-1 (7-37)

Incretin Hormone · Native Peptide

~2 minHalf-lifeAlavi 2021 Ding 2017

3297.7 DaMolecular weightAlavi 2021

1922Discovery year

Research use only · IV/SC in experimental settings

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

01Mechanism of Action

Parameter

GLP-1 (7-37)

Melanotan-II

Primary target

GLP-1 receptor (class B GPCR)Koole 2015

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

Pathway

GLP-1R activation → cAMP production → PKA signaling → insulin secretion (pancreatic β-cells)Lu 2025 Koole 2015

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

Downstream effect

Glucose-dependent insulin release, glucagon suppression, delayed gastric emptying, reduced food intakeLu 2025 Ding 2017

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

Feedback intact?

Yes — physiological secretion and degradation preserved

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Origin

Endogenous peptide cleaved from proglucagon in intestinal L cells; secreted postprandially

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

Antibody development

—

02Dosage Protocols

Parameter

GLP-1 (7-37)

Melanotan-II

Clinical use

None — native GLP-1 not used therapeutically

Engineered analogues (semaglutide, liraglutide) used clinically.Friedman 2024

—

Research dosing

Variable — 0.1–10 nmol/kg in animal models

Used as reference standard for analogue comparison.

—

Half-life

~2 minutes (plasma)Alavi 2021 Ding 2017

Requires continuous infusion for sustained effect.

~1 hour plasma; effects on melanocytes persist days

Modified analogues

t½ extended to 13 h (liraglutide), 165 h (semaglutide)

Via DPP-4 resistance + fatty acid acylation.

—

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

Lower / starter dose

—

0.1 mg / day

Conservative starter — assess tolerability for nausea.

Evidence basis

—

Phase 1 + anecdotalDorr 1996

Duration

—

8–12 weeks per cycle

Reconstitution

—

Bacteriostatic water; protect from light

Timing

—

Evening preferred (24h tan-development cycle)

03Metabolic / Fat Loss Evidence

Parameter

GLP-1 (7-37)

Melanotan-II

Mechanism

GLP-1R activation in hypothalamic satiety centers (arcuate nucleus) reduces food intakeLu 2025

Effect demonstrated with long-acting analogues (liraglutide).Lu 2025

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Native GLP-1 efficacy

Minimal — rapid degradation prevents sustained appetite suppression

—

Gastric emptying

Delayed in animal models, contributing to satiety

—

Body weight impact

Not observed with native GLP-1 — requires analogue formulations

—

04Side Effects & Safety

Parameter

GLP-1 (7-37)

Melanotan-II

Native GLP-1

Well-tolerated in research settings; no prolonged exposure data

—

Hypoglycemia risk

Low — insulin secretion is glucose-dependent

—

Analogue side effects

Nausea, vomiting, diarrhea (GLP-1R agonists)

Not applicable to native GLP-1 due to non-therapeutic use.

—

GLP-1 resistance

High glucose-induced PKCβ overexpression may reduce GLP-1 responsiveness in endothelial cellsPujadas 2016

—

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

Absolute Contraindications

GLP-1 (7-37)

—

Melanotan-II

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

Relative Contraindications

GLP-1 (7-37)

—

Melanotan-II

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

05Administration Protocol

Parameter

GLP-1 (7-37)

Melanotan-II

1. Research use only

Native GLP-1(7-37) is not formulated for therapeutic use. Administered IV or SC in experimental protocols to study GLP-1R pharmacology and as reference standard for analogue development.

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

2. Storage

Lyophilised peptide stored at -20°C or below. Reconstituted solutions should be prepared fresh and used immediately due to rapid degradation.

SQ — abdomen. Rotate sites.

3. Clinical alternatives

For therapeutic GLP-1R activation, use FDA-approved long-acting analogues: semaglutide (once weekly), liraglutide (once daily), dulaglutide (once weekly), or exenatide (twice daily or once weekly).

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

4. Storage

—

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

5. Needle

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29–31G insulin syringe.