Side-by-side · Research reference

GHRP-2vsMazdutide

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

BPhase 3HUMAN-REVIEWED19/62 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

Mazdutide

GLP-1/Glucagon Dual Agonist · Oxyntomodulin Analogue · Phase 3

9 mgWeekly doseJi 2026

12.4%Weight lossAzam 2026

Phase 3Status (China)

SQ · Abdomen · Once WeeklyJi 2026

01Mechanism of Action

Parameter

GHRP-2

Mazdutide

Primary target

Ghrelin receptor (GHS-R1a) on anterior pituitaryBowers 1990

GLP-1 receptor and glucagon receptorAbdul 2026 Elmendorf 2026

Pathway

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

Dual agonism: GLP-1R → satiety, insulin secretion, gastric emptying delay; GCGR → hepatic lipolysis, energy expenditure, thermogenesisElmendorf 2026 Abulehia 2026

Downstream effect

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

Weight loss via appetite suppression (GLP-1 axis) and increased energy expenditure (glucagon axis); improved glycemic control in T2D

Feedback intact?

Yes, with somatostatin feedback active

Yes — physiological receptor-mediated signaling preserved

Origin

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

Synthetic oxyntomodulin analogue — endogenous peptide with dual GLP-1/glucagon activity

Antibody development

—

02Dosage Protocols

Parameter

GHRP-2

Mazdutide

Standard dose

100–300 mcg per injectionBowers 1990

—

Frequency

1–3× per day

Once weeklyJi 2026 Luo 2026

Lower / starter dose

50 mcg per dose

—

Evidence basis

Phase 2 + clinical diagnostic useBowers 1990

Phase 2 RCT / Phase 3 ongoingJi 2026 Luo 2026

Duration

8–12 weeks on / 4 off (anecdotal)

—

Reconstitution

Bacteriostatic water

—

Timing

Pre-sleep + fasted preferred

—

Half-life

~30 minMalagón 1999

—

Phase 2 studied dose

—

9 mg / weekJi 2026

Highest efficacy dose in obesity trial (BMI ≥30 kg/m²).Ji 2026

Route

—

SubcutaneousJi 2026

Dose escalation

—

3 mg → 6 mg → 9 mg (titration schedule in trials)

Gradual escalation to minimize GI side effects.

Duration (trials)

—

24–48 weeks

Population

—

Non-diabetic adults BMI ≥30 kg/m² or ≥27 kg/m² with comorbidities

Phase 3 comparator

—

Semaglutide 1 mg/week (DREAMS-3 trial)Luo 2026

03Metabolic / Fat Loss Evidence

Parameter

GHRP-2

Mazdutide

Percentage body weight loss

—

12.4% (pooled meta-analysis, 9 mg dose)

95% CI: -16.15% to -8.68%, random-effects model.Azam 2026

Absolute weight loss

—

9.8 kg (mean)Azam 2026

95% CI: -13.15 to -6.37 kg.Azam 2026

Responder rate (≥10% loss)

—

Not explicitly reported in available abstracts

Mechanism

—

Appetite suppression (GLP-1) + energy expenditure (glucagon)Elmendorf 2026

BMI reduction

—

Significant reduction in Chinese adults BMI ≥30 kg/m²Ji 2026

Visceral fat

—

Expected benefit from glucagon-mediated lipolysis (not quantified in abstracts)

Glycemic improvement

—

HbA1c reduction in T2D cohort (Phase 3 DREAMS-3)

Comparator efficacy

—

Head-to-head vs semaglutide 1 mg (Phase 3 pending publication)Luo 2026

Key publications

—

Ji et al. Med 2026 · Azam et al. Diab Obes Metab 2026 · Luo et al. Contemp Clin Trials 2026

04Side Effects & Safety

Parameter

GHRP-2

Mazdutide

Cortisol elevation

Mild but measurableBowers 1990

—

Prolactin elevation

Mild but measurable

—

Hunger

Strong appetite increase

—

Injection site reaction

Mild erythema

—

IGF-1 elevation

Strong; monitor with chronic high-dose use

—

Cancer risk

Contraindicated in active malignancy

—

Pregnancy / OB

Avoid

—

Gastrointestinal symptoms

—

Nausea, vomiting, diarrhea (most common, GLP-1 effect)

Injection site reactions

—

Erythema, pruritus, local discomfort

Hypoglycemia

—

Low risk in non-diabetic cohort; monitor in T2D with insulin or sulfonylureas

Cardiovascular effects

—

Increased heart rate (glucagon effect, transient)

Pancreatitis risk

—

Theoretical (incretin class effect); monitor amylase/lipase if abdominal pain

Thyroid C-cell tumors

—

Black box warning for GLP-1 class (rodent data); human relevance unclear

Gallbladder disease

—

Cholelithiasis, cholecystitis (rapid weight loss effect)

Tolerability

—

Generally well-tolerated; GI effects diminish with dose titration

Absolute Contraindications

GHRP-2

·Active malignancy
·Pregnancy / breastfeeding

Mazdutide

·Personal or family history of medullary thyroid carcinoma
·Multiple endocrine neoplasia syndrome type 2 (MEN 2)
·Hypersensitivity to mazdutide or excipients
·Pregnancy

Relative Contraindications

GHRP-2

·Untreated diabetes

Mazdutide

·History of pancreatitis
·Severe gastroparesis or GI motility disorders
·Diabetic retinopathy (monitor, risk of worsening with rapid glycemic change)
·Renal impairment (limited data, use with caution)

05Administration Protocol

Parameter

GHRP-2

Mazdutide

1. Reconstitution

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

Supplied as pre-filled pen or reconstituted vial (per manufacturer instructions). Inspect solution — should be clear, colorless to pale yellow. Discard if cloudy or particulate matter present.

2. Injection site

SQ — abdomen or thigh. Rotate sites.

Subcutaneous — abdomen preferred, also thigh or upper arm. Rotate sites weekly. Avoid areas with scarring, moles, or active inflammation.

3. Timing

Pre-sleep + fasted preferred.

Once weekly, same day each week. May be taken with or without food. If dose missed, administer within 3 days; if >3 days, skip and resume next scheduled dose.

4. Storage

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

Refrigerate 2–8 °C. Do not freeze. May be kept at room temperature (<25 °C) for up to 14 days if needed. Protect from light.

5. Needle

29–31G, 4–8 mm insulin syringe.

Use supplied needle or compatible insulin syringe (if reconstituting). Pinch skin, inject at 90° angle. Hold 5–10 seconds before withdrawing needle to prevent leakage.

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

Mazdutide

— no documented stacks