Side-by-side · Research reference

GHRP-6vsHumanin

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

BAnimal-StrongHUMAN-REVIEWED14/52 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

Humanin

Mitochondrial-Derived Peptide · Cytoprotective

24-AAPeptide lengthZhu 2022

mtDNAEncoded originZhu 2022 Shahzaib 2026

Bax/BimPrimary targetZhu 2022 Morris 2021

SQ · Experimental

01Mechanism of Action

Parameter

GHRP-6

Humanin

Primary target

Ghrelin receptor (GHS-R1a)Bowers 1990

Intracellular: Bax, Bim, tBid (pro-apoptotic Bcl-2 family). Extracellular: FPRL1/2 G-protein-coupled receptorsZhu 2022 Lue 2021

Pathway

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

Humanin binds Bax/Bim → inhibits mitochondrial outer membrane permeabilization (MOMP) → blocks cytochrome c release → prevents caspase activation → cell survival

Downstream effect

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

Suppression of apoptosis, mitochondrial stabilization, reduced oxidative stress, preservation of germ cells and neurons under stressZhu 2022 Lue 2021 Velentza 2024

Feedback intact?

—

Not applicable — peptide acts as anti-apoptotic signal, not hormonal axis

Origin

Synthetic hexapeptide; first-generation GHRP from Bowers groupBowers 1990

Encoded by short open reading frame in mitochondrial 16S rRNA gene (MTRNR2). 24-28 amino acids. 13 homologous variants (MTRNR2L1-L13) identified.Zhu 2022 Shahzaib 2026

Antibody development

—

Not reported in animal models

02Dosage Protocols

Parameter

GHRP-6

Humanin

Standard dose

100–200 mcg per injectionBowers 1990

—

Frequency

1–3× per day

Daily (IP)

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 1 + clinical practiceBowers 1990

Animal models (rat, mouse)Huang 2025 El 2022 Velentza 2024

Duration

8–12 weeks on / 4 off

8–12 weeks in animal studies

Reconstitution

Bacteriostatic water

—

Timing

Pre-meal preferred for appetite support

—

Half-life

~15 minMalagón 1999

—

Standard experimental dose (HNG)

—

4 mg/kg IP (rat)

Most common dose in rodent models.

Ex vivo bone culture

—

1 µg/mL

Protective against venetoclax-induced bone growth retardation.

Human data

—

None — no clinical trials reported

Analog (HNG)

—

Gly[14]-humanin — more potent variant

Substitution at position 14 enhances cytoprotective activity.

03Metabolic / Fat Loss Evidence

Parameter

GHRP-6

Humanin

Direct fat loss evidence

—

None

Mechanism overlap

—

Mitochondrial health may indirectly influence metabolic efficiency, but no quantified effect

04Side Effects & Safety

Parameter

GHRP-6

Humanin

Hunger

Pronounced — defining feature vs ipamorelin

—

Cortisol elevation

Mild

—

Prolactin elevation

Mild

—

Injection site reaction

Mild

Not reported in animal studies (IP route)

Cancer risk

Contraindicated in active malignancy

—

Pregnancy / OB

Avoid

—

Animal model safety

—

Well-tolerated in rat and mouse studies at 4 mg/kg for 8–12 weeks

Human safety data

—

None — no clinical trials

Theoretical fibrillation risk

—

Induces amyloid-like fibrillation of Bax/BID. Long-term sequelae unknown.

Reproductive safety

—

Protective in POI model (cyclophosphamide-induced), no adverse effects on fertility notedHuang 2025

Absolute Contraindications

GHRP-6

·Active malignancy
·Pregnancy / breastfeeding

Humanin

·Unknown — no human data

Relative Contraindications

GHRP-6

·Severe insulin resistance (appetite-driven caloric load)

Humanin

·Active malignancy (theoretical risk of anti-apoptotic effect on tumour cells)

05Administration Protocol

Parameter

GHRP-6

Humanin

1. Reconstitution

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

Intraperitoneal (IP) in animal models. Subcutaneous route untested. No human protocols exist.

2. Injection site

SQ — abdomen. Rotate sites.

Synthetic peptide reconstituted in sterile saline or PBS. No commercial formulation available.

3. Timing

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

Daily administration in animal studies. Optimal timing not characterized.

4. Storage

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

Lyophilised powder: -20 °C. Reconstituted: 4 °C, use within 7 days. Avoid freeze-thaw cycles.

5. Needle

29–31G, 4–8 mm insulin syringe.

No FDA approval, no IND, no clinical trials. Experimental research tool only.

06Stack Synergy

GHRP-6

— no documented stacks

Humanin

+ MOTS-c

Multi-pathway

View MOTS-c →

Both are mitochondrial-derived peptides. MOTS-c enhances metabolic efficiency and insulin sensitivity via AMPK activation, while humanin prevents mitochondrial apoptosis. Combined, they address mitochondrial function (MOTS-c) and survival signaling (humanin), supporting cellular resilience under metabolic and oxidative stress.

Humanin: 4 mg/kg IP · daily (animal model)
MOTS-c: 5 mg/kg IP · daily (animal model)
Frequency: Once daily
Primary benefit: Mitochondrial health, metabolic efficiency, anti-apoptotic signaling