Side-by-side · Research reference

GHRP-2vsHumanin

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

BAnimal-StrongHUMAN-REVIEWED14/52 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

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-2

Humanin

Primary target

Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 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 vesicle exocytosisBowers 2002

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

Downstream effect

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

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

Feedback intact?

Yes, with somatostatin feedback active

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

Origin

Synthetic hexapeptide; developed by Bowers/Tulane group in the 1980sBowers 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-2

Humanin

Standard dose

100–300 mcg per injectionBowers 1990

—

Frequency

1–3× per day

Daily (IP)

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 2 + clinical diagnostic useBowers 1990

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

Duration

8–12 weeks on / 4 off (anecdotal)

8–12 weeks in animal studies

Reconstitution

Bacteriostatic water

—

Timing

Pre-sleep + fasted preferred

—

Half-life

~30 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-2

Humanin

Direct fat loss evidence

—

None

Mechanism overlap

—

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

04Side Effects & Safety

Parameter

GHRP-2

Humanin

Cortisol elevation

Mild but measurableBowers 1990

—

Prolactin elevation

Mild but measurable

—

Hunger

Strong appetite increase

—

Injection site reaction

Mild erythema

Not reported in animal studies (IP route)

IGF-1 elevation

Strong; monitor with chronic high-dose use

—

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-2

·Active malignancy
·Pregnancy / breastfeeding

Humanin

·Unknown — no human data

Relative Contraindications

GHRP-2

·Untreated diabetes

Humanin

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

05Administration Protocol

Parameter

GHRP-2

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 or thigh. Rotate sites.

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

3. Timing

Pre-sleep + fasted preferred.

Daily administration in animal studies. Optimal timing not characterized.

4. Storage

Lyophilised: room temp, light-protected. 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-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

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