Side-by-side · Research reference

GHRP-6vsGLP-1 (7-37)

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

APhase 1HUMAN-REVIEWED10/36 cited

BHuman-MechanisticHUMAN-REVIEWED16/43 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

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

01Mechanism of Action

Parameter

GHRP-6

GLP-1 (7-37)

Primary target

Ghrelin receptor (GHS-R1a)Bowers 1990

GLP-1 receptor (class B GPCR)Koole 2015

Pathway

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

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

Downstream effect

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

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

Feedback intact?

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Yes — physiological secretion and degradation preserved

Origin

Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990

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

Antibody development

—

02Dosage Protocols

Parameter

GHRP-6

GLP-1 (7-37)

Standard dose

100–200 mcg per injectionBowers 1990

—

Frequency

1–3× per day

—

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 1 + clinical practiceBowers 1990

—

Duration

8–12 weeks on / 4 off

—

Reconstitution

Bacteriostatic water

—

Timing

Pre-meal preferred for appetite support

—

Half-life

~15 minMalagón 1999

~2 minutes (plasma)Alavi 2021 Ding 2017

Requires continuous infusion for sustained effect.

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.

Modified analogues

—

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

Via DPP-4 resistance + fatty acid acylation.

03Metabolic / Fat Loss Evidence

Parameter

GHRP-6

GLP-1 (7-37)

Mechanism

—

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

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

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

GHRP-6

GLP-1 (7-37)

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

—

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

Absolute Contraindications

GHRP-6

·Active malignancy
·Pregnancy / breastfeeding

GLP-1 (7-37)

—

Relative Contraindications

GHRP-6

·Severe insulin resistance (appetite-driven caloric load)

GLP-1 (7-37)

—

05Administration Protocol

Parameter

GHRP-6

GLP-1 (7-37)

1. Reconstitution

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

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.

2. Injection site

SQ — abdomen. Rotate sites.

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

3. Timing

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

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).

4. Storage

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

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5. Needle

29–31G, 4–8 mm insulin syringe.

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