Side-by-side · Research reference

MazdutidevsSermorelin

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

APhase 3HUMAN-REVIEWED19/62 cited

BPhase 3HUMAN-REVIEWED14/43 cited

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

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

Mazdutide

Sermorelin

Primary target

GLP-1 receptor and glucagon receptorAbdul 2026 Elmendorf 2026

Pituitary GHRH receptorWalker 1994

Pathway

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

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

Downstream effect

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

Pulsatile GH release; subsequent IGF-1 elevationMolteno 2013

Feedback intact?

Yes — physiological receptor-mediated signaling preserved

Yes — short pulse preserves feedback

Origin

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

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

Antibody development

—

02Dosage Protocols

Parameter

Mazdutide

Sermorelin

Phase 2 studied dose

9 mg / weekJi 2026

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

—

Frequency

Once weeklyJi 2026 Luo 2026

Once daily, pre-sleep

Route

SubcutaneousJi 2026

—

Dose escalation

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

Gradual escalation to minimize GI side effects.

—

Evidence basis

Phase 2 RCT / Phase 3 ongoingJi 2026 Luo 2026

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

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

—

Standard dose

—

100–500 mcg per injectionMolteno 2013

Lower / starter dose

—

100 mcg per dose

Duration

—

8–12 weeks per cycle

Reconstitution

—

Bacteriostatic water

Timing

—

Pre-sleep, fasted preferred

Half-life

—

~12 min (plasma)Molteno 2013

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

03Metabolic / Fat Loss Evidence

Parameter

Mazdutide

Sermorelin

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

Mazdutide

Sermorelin

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

—

Injection site reaction

—

Mild erythema, transient pain

Flushing / headache

—

Common transient effect

IGF-1 elevation

—

Modest at standard doses

Cancer risk

—

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

Pregnancy / OB

—

Avoid

Glucose handling

—

Generally neutral

Absolute Contraindications

Mazdutide

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

Sermorelin

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

Relative Contraindications

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)

Sermorelin

·Untreated diabetes

05Administration Protocol

Parameter

Mazdutide

Sermorelin

1. Preparation

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.

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

2. Injection site

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

SQ — abdomen or thigh. Rotate sites.

3. Timing

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.

Pre-sleep, fasted.

4. Storage

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.

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

5. Needle technique

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.

29–31G, 4–8 mm insulin syringe.

06Stack Synergy

Mazdutide

— 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