Side-by-side · Research reference

GHRP-6vsSermorelin

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 3Reviewed14/43 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

Sermorelin

GHRH 1-29 fragment · Short-acting

100–500 mcgPer doseMolteno 2013

Phase 3Evidence levelWalker 1994 Molteno 2013

~12 minHalf-lifeMolteno 2013

SQ · Pre-sleep · 1×/day

01Mechanism of Action

Parameter

GHRP-6

Sermorelin

Primary target

Ghrelin receptor (GHS-R1a)Bowers 1990

Pituitary GHRH receptorWalker 1994

Pathway

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

GHRH-R → Gαs → cAMP → PKA → GH vesicle exocytosisWalker 1994

Downstream effect

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

Pulsatile GH release; subsequent IGF-1 elevationMolteno 2013

Feedback intact?

—

Yes — short pulse preserves feedback

Origin

Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990

Unmodified active 29-AA fragment of human GHRH (1-44)Walker 1994

Antibody development

—

02Dosage Protocols

Parameter

GHRP-6

Sermorelin

Standard dose

100–200 mcg per injectionBowers 1990

100–500 mcg per injectionMolteno 2013

Frequency

1–3× per day

Once daily, pre-sleep

Lower / starter dose

50 mcg per dose

100 mcg per dose

Evidence basis

Phase 1 + clinical practiceBowers 1990

Phase 3 (Geref pediatric); clinical practiceWalker 1994 Molteno 2013

Duration

8–12 weeks on / 4 off

8–12 weeks per cycle

Reconstitution

Bacteriostatic water

Timing

Pre-meal preferred for appetite support

Pre-sleep, fasted preferred

Half-life

~15 minMalagón 1999

~12 min (plasma)Molteno 2013

Shorter than tesamorelin (~26 min) — simpler GHRH analogue.

04Side Effects & Safety

Parameter

GHRP-6

Sermorelin

Hunger

Pronounced — defining feature vs ipamorelin

—

Cortisol elevation

Mild

—

Prolactin elevation

Mild

—

Injection site reaction

Mild

Mild erythema, transient pain

Cancer risk

Contraindicated in active malignancy

Contraindicated in active malignancy (GH/IGF-1 axis)

Pregnancy / OB

Avoid

Flushing / headache

—

Common transient effect

IGF-1 elevation

—

Modest at standard doses

Glucose handling

—

Generally neutral

Absolute Contraindications

GHRP-6

·Active malignancy
·Pregnancy / breastfeeding

Sermorelin

·Active malignancy
·Pregnancy / breastfeeding
·Disrupted hypothalamic-pituitary axis

Relative Contraindications

GHRP-6

·Severe insulin resistance (appetite-driven caloric load)

Sermorelin

·Untreated diabetes

05Administration Protocol

Parameter

GHRP-6

Sermorelin

1. Reconstitution

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

Add 2 mL bacteriostatic water to 5 mg vial → 2.5 mg/mL = 250 mcg per 0.1 mL.

2. Injection site

SQ — abdomen. Rotate sites.

SQ — abdomen or thigh. Rotate sites.

3. Timing

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

Pre-sleep, fasted.

4. Storage

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

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

5. Needle

29–31G, 4–8 mm insulin syringe.

06Stack Synergy

GHRP-6

— no documented stacks

Sermorelin

+ Ipamorelin

Strong

View Ipamorelin →

Sermorelin (GHRH analogue) and ipamorelin (selective GHRP) form the prototypical GHRH+GHRP dual-axis stack at the lowest cost. Both peak within 30 min and produce a sharp physiological GH pulse without cortisol/prolactin elevation.

Sermorelin: 200–300 mcg SQ · pre-sleep
Ipamorelin: 200–300 mcg SQ · same injection
Primary benefit: Pulsatile GH stimulation, recovery, body composition

Raun 1998 Walker 1994