Side-by-side · Research reference

GHRP-2vsMT-1

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

APhase 2HUMAN-REVIEWED15/42 cited

BFDA-ApprovedHUMAN-REVIEWED9/51 cited

GHRP-2

Hexapeptide GHRP · Phase 2 (clinical diagnostic)

100–300 mcgPer doseBowers 1990

Phase 2Evidence levelBowers 1990 Sigalos 2018

~30 minHalf-lifeMalagón 1999

SQ · Multiple sites · 1–3×/day

MT-1

α-MSH Analogue · FDA-Approved

16 mgImplant dose

13 AAPeptide lengthChawathe 2026

2019FDA approval

SQ Implant · 60-Day Release

01Mechanism of Action

Parameter

GHRP-2

MT-1

Primary target

Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 1990

Melanocortin-1 receptor (MC1R) on melanocytesLangan 2010

Pathway

GHS-R1a → Gαq → Ca²⁺ → GH vesicle exocytosisBowers 2002

α-MSH analogue → MC1R activation → cAMP elevation → MITF transcription → eumelanin synthesis

Downstream effect

Strong GH pulse + IGF-1 elevation; appetite increase via ghrelin agonismBowers 2002

Increased melanogenesis, photoprotection, reduced UV sensitivityLangan 2010

Feedback intact?

Yes, with somatostatin feedback active

Yes — exogenous MC1R agonism does not suppress endogenous α-MSH production

Origin

Synthetic hexapeptide; developed by Bowers/Tulane group in the 1980sBowers 1990

Synthetic 13-AA peptidomimetic with norleucine (position 4) and D-phenylalanine (position 7) substitutions for metabolic stabilityChawathe 2026

Antibody development

—

02Dosage Protocols

Parameter

GHRP-2

MT-1

Standard dose

100–300 mcg per injectionBowers 1990

16 mg subcutaneous implant

FDA-approved formulation (Scenesse).

Frequency

1–3× per day

Every 60 days

Sustained release implant — no daily administration required.

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 2 + clinical diagnostic useBowers 1990

Phase 3 RCT / FDA-approved orphan drug

Duration

8–12 weeks on / 4 off (anecdotal)

Seasonal use (spring–autumn typical)

Aligned with peak UV exposure months.

Reconstitution

Bacteriostatic water

—

Timing

Pre-sleep + fasted preferred

—

Half-life

~30 minMalagón 1999

—

Indication

—

Erythropoietic protoporphyria (EPP)

Narrow FDA approval — not licensed for cosmetic tanning.

Route

—

Subcutaneous implant — upper arm or abdomen

Stability

—

Norleucine/D-Phe substitutions enhance peptidase resistance

Modified structure vs endogenous α-MSH (Met⁴, L-Phe⁷).

04Side Effects & Safety

Parameter

GHRP-2

MT-1

Cortisol elevation

Mild but measurableBowers 1990

—

Prolactin elevation

Mild but measurable

—

Hunger

Strong appetite increase

—

Injection site reaction

Mild erythema

—

IGF-1 elevation

Strong; monitor with chronic high-dose use

—

Cancer risk

Contraindicated in active malignancy

—

Pregnancy / OB

Avoid

—

Nausea

—

Common (>10%) — mild, transient

Implant site reaction

—

Erythema, bruising, tenderness at insertion site

Hyperpigmentation

—

Generalised tanning (therapeutic effect), darkening of freckles/neviLangan 2010 Habbema 2017

Expected melanogenic response — complicates pigmented lesion surveillance.

Melanocytic changes

—

Rapid pigmentation of existing nevi; new melanocytic lesions reported with unregulated useHabbema 2017

Requires dermatologic monitoring; theoretical melanoma concern with chronic stimulation.

Headache

—

Occasional (MC1R-independent melanocortin effects)

Photosensitivity (paradoxical)

—

Rare phototoxic reactions despite melanin increase

Contamination risk (unregulated)

—

Impurity, infection, blood-borne virus transmission from illicit melanotan productsLangan 2010 Habbema 2017

Applies to internet/gym-sourced 'melanotan' — not FDA-approved Scenesse.

Absolute Contraindications

GHRP-2

·Active malignancy
·Pregnancy / breastfeeding

MT-1

·Hypersensitivity to afamelanotide or excipients
·Hepatic impairment (no safety data)
·Renal impairment (no safety data)

Relative Contraindications

GHRP-2

·Untreated diabetes

MT-1

·History of melanoma or atypical nevi (melanocortin receptor stimulation concern)Habbema 2017
·Pregnancy/lactation (insufficient data)
·Photosensitive dermatoses (other than EPP)

05Administration Protocol

Parameter

GHRP-2

MT-1

1. Reconstitution

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

Performed by trained healthcare provider. Sterile technique. Small incision in upper arm (triceps) or lower abdomen using trocar. 16 mg rod (4 mm × 1.5 cm) inserted subcutaneously.

2. Injection site

SQ — abdomen or thigh. Rotate sites.

Pressure applied post-insertion. Sterile dressing × 24 hrs. Avoid strenuous activity for 24–48 hrs to prevent extrusion.

3. Timing

Pre-sleep + fasted preferred.

Slow biodegradable polymer matrix releases afamelanotide over 60 days, maintaining therapeutic plasma levels without daily dosing.

4. Storage

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

New implant every 60 days during high UV season (spring–autumn in temperate climates). Rotate implant sites to avoid scarring.

5. Needle

29–31G, 4–8 mm insulin syringe.

Baseline and periodic dermatologic exams to document pigmented lesions. Patient education on self-examination for new/changing nevi.

06Stack Synergy

GHRP-2

+ CJC-1295 (no DAC)

Strong

View CJC-1295 (no DAC) →

GHRP-2 + CJC-1295-no-DAC is a higher-amplitude alternative to the ipamorelin + CJC-1295 stack. GHRP-2 produces a stronger pulse but with cortisol + prolactin signal — choose when maximum GH amplitude is the goal and the side-effect tolerance is acceptable.

GHRP-2: 100–200 mcg SQ · pre-sleep
CJC-1295 (no DAC): 100 mcg SQ · same injection
Primary benefit: High-amplitude GH pulse, body composition

Bowers 1990 Teichman 2006

MT-1

— no documented stacks