Side-by-side · Research reference

GHRP-6vsMelanotan-II

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

APhase 1Reviewed10/36 cited

BPhase 1Reviewed9/43 cited

GHRP-6

Hexapeptide GHRP · Strong appetite stimulant

100–200 mcgPer doseBowers 1990

Phase 1Evidence levelBowers 1990

~15 minHalf-lifeMalagón 1999

SQ · Multiple sites · 1–3×/day

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

GHRP-6

Melanotan-II

Primary target

Ghrelin receptor (GHS-R1a)Bowers 1990

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

Pathway

GHS-R1a → Gαq → Ca²⁺ → GH release; central appetite driveBowers 2002

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

Downstream effect

GH pulse + strong appetite stimulation; modest IGF-1 elevationBowers 2002

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

Feedback intact?

—

Origin

Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990

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

Antibody development

—

02Dosage Protocols

Parameter

GHRP-6

Melanotan-II

Standard dose

100–200 mcg per injectionBowers 1990

—

Frequency

1–3× per day

Daily during loading; 1–2× per week maintenance

Lower / starter dose

50 mcg per dose

0.1 mg / day

Conservative starter — assess tolerability for nausea.

Evidence basis

Phase 1 + clinical practiceBowers 1990

Phase 1 + anecdotalDorr 1996

Duration

8–12 weeks on / 4 off

8–12 weeks per cycle

Reconstitution

Bacteriostatic water

Bacteriostatic water; protect from light

Timing

Pre-meal preferred for appetite support

Evening preferred (24h tan-development cycle)

Half-life

~15 minMalagón 1999

~1 hour plasma; effects on melanocytes persist days

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.

04Side Effects & Safety

Parameter

GHRP-6

Melanotan-II

Hunger

Pronounced — defining feature vs ipamorelin

—

Cortisol elevation

Mild

—

Prolactin elevation

Mild

—

Injection site reaction

Mild

—

Cancer risk

Contraindicated in active malignancy

—

Pregnancy / OB

Avoid

Contraindicated

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

Absolute Contraindications

GHRP-6

·Active malignancy
·Pregnancy / breastfeeding

Melanotan-II

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

Relative Contraindications

GHRP-6

·Severe insulin resistance (appetite-driven caloric load)

Melanotan-II

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

05Administration Protocol

Parameter

GHRP-6

Melanotan-II

1. Reconstitution

Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL.

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

2. Injection site

SQ — abdomen. Rotate sites.

3. Timing

Pre-meal for appetite support; pre-sleep for GH alignment.

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

4. Storage

Lyophilised: room temp. Reconstituted: refrigerate ≤30 days.

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

5. Needle

29–31G, 4–8 mm insulin syringe.

29–31G insulin syringe.