Side-by-side · Research reference

GHRP-2vsGHRP-6

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

APhase 2Reviewed15/42 cited

BPhase 1Reviewed10/36 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

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

01Mechanism of Action

Parameter

GHRP-2

GHRP-6

Primary target

Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 1990

Ghrelin receptor (GHS-R1a)Bowers 1990

Pathway

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

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

Downstream effect

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

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

Feedback intact?

Yes, with somatostatin feedback active

—

Origin

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

Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990

Antibody development

—

02Dosage Protocols

Parameter

GHRP-2

GHRP-6

Standard dose

100–300 mcg per injectionBowers 1990

100–200 mcg per injectionBowers 1990

Frequency

1–3× per day

Lower / starter dose

50 mcg per dose

Evidence basis

Phase 2 + clinical diagnostic useBowers 1990

Phase 1 + clinical practiceBowers 1990

Duration

8–12 weeks on / 4 off (anecdotal)

8–12 weeks on / 4 off

Reconstitution

Bacteriostatic water

Timing

Pre-sleep + fasted preferred

Pre-meal preferred for appetite support

Half-life

~30 minMalagón 1999

~15 minMalagón 1999

04Side Effects & Safety

Parameter

GHRP-2

GHRP-6

Cortisol elevation

Mild but measurableBowers 1990

Mild

Prolactin elevation

Mild but measurable

Mild

Hunger

Strong appetite increase

Pronounced — defining feature vs ipamorelin

Injection site reaction

Mild erythema

Mild

IGF-1 elevation

Strong; monitor with chronic high-dose use

—

Cancer risk

Contraindicated in active malignancy

Pregnancy / OB

Avoid

Absolute Contraindications

GHRP-2

·Active malignancy
·Pregnancy / breastfeeding

GHRP-6

·Active malignancy
·Pregnancy / breastfeeding

Relative Contraindications

GHRP-2

·Untreated diabetes

GHRP-6

·Severe insulin resistance (appetite-driven caloric load)

05Administration Protocol

Parameter

GHRP-2

GHRP-6

1. Reconstitution

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

2. Injection site

SQ — abdomen or thigh. Rotate sites.

SQ — abdomen. Rotate sites.

3. Timing

Pre-sleep + fasted preferred.

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

4. Storage

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

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

5. Needle

29–31G, 4–8 mm insulin syringe.

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

GHRP-6

— no documented stacks