Mazdutide side effects and risks

Reported side effects

• Vomiting: GLORY 2 9 mg: 53.1% vs 1.3% placebo., moderate (source)
• Nausea: GLORY 2 9 mg: 46.9% vs 3.2% placebo., moderate (source)
• Diarrhea: GLORY 2 9 mg: 39.4% vs 6.5% placebo., moderate (source)
• Constipation: Early 16 mg cohorts: 16.7% and 33.3%; placebo: 12.5%., moderate (source)
• Fatigue: Early 16 mg cohorts: 25.0% and 75.0%; placebo: 0%., moderate (source)
• Low blood sugar: Phase 2 diabetes: 10% pooled mazdutide vs 8% placebo., moderate (source)
• Injection site reaction: Phase 2 obesity: 4.8%/1.6%/3.3% at 3/4.5/6 mg; placebo: 6.5%., mild (source)
• Heart rate increase: Observed in early trials; incidence depends on how the event was defined., moderate (source)
• Pancreatitis, severe allergy or dehydration-related kidney injury: Class concerns; available trials cannot establish reliable rare event rates., serious (source)

Stop and get help if

• Severe or persistent belly pain, especially into the back: Stop dosing and get urgent medical assessment.
• Trouble breathing; swelling of lips, tongue or throat: Call emergency services now.
• Chest pain, fainting or a sustained racing heart: Seek emergency care.
• Sudden vision loss or a major vision change: Seek urgent eye/emergency assessment.
• Confusion, seizure or low blood sugar that does not resolve: Call emergency services; do not take another dose.
• Repeated vomiting, inability to keep fluids down or very little urine: Get urgent care for dehydration or kidney injury.
• Belly swelling with vomiting and inability to pass stool or gas: Seek urgent medical assessment.
• Fever or spreading redness, heat or swelling after an injection: Get urgent medical care for possible infection.

Who should avoid it

• pregnant: Excluded from trials; no established pregnancy safety.
• breastfeeding: No established infant safety; avoid exposure while breastfeeding.
• tryingToConceive: Plan stopping and contraception with a clinician; no verified compound-specific washout is given here.
• under18: Pediatric safety and dosing remain limited.
• mtcOrMen2: Personal/family medullary thyroid cancer or MEN2 was excluded. Human thyroid-cancer risk is not established.
• eatingDisorderHistory: Appetite suppression may worsen restrictive eating; this is a precautionary screen.
• pancreatitisHistory: Review prior pancreatitis before exposure; this is also a GLP-1 class precaution.
• gallbladderDisease: Gallbladder symptoms need review during substantial weight loss.
• gastroparesis: Delayed stomach emptying can worsen severe stomach-motility problems.
• diabeticRetinopathy: Rapid glucose improvement can worsen existing eye disease; direct long-term risk is uncertain.
• kidneyDisease: Vomiting and diarrhea can cause dehydration and kidney injury. Special-population data are incomplete.
• liverDisease: Advanced liver disease needs specialist review; trial findings do not establish self-dosing.
• heartCondition: Heart rate rose in early trials; review rhythm problems and symptoms.
• uncontrolledBloodPressure: Review uncontrolled pressure before use; blood pressure changes and dehydration need monitoring.
• surgeryPlanned: Tell the anesthesia team about use; delayed stomach emptying can raise aspiration risk.
• other: Prior severe reaction to this compound or its ingredients should stop re-exposure.
• testedAthlete: No named 2026 prohibition found. China approval changes the S0 analysis; confirm with the anti-doping authority.

Interactions

• Insulin: Additive low-glucose risk; insulin doses may need clinician adjustment.
• Sulfonylureas: Additive low-glucose risk; review dose and glucose checks.
• Other GLP-1 or related appetite injections: Overlapping actions may worsen stomach symptoms and dehydration. No verified home stack has a tested dose.
• Narrow-window oral medicines: Slower stomach emptying or vomiting may alter exposure. Monitoring needs are medicine-specific.
• Oral contraception: Vomiting may reduce pill reliability. A tirzepatide-specific backup rule cannot be assumed for this drug.
• Oral anticoagulants: Illness and poor intake may change anticoagulation. No direct interaction magnitude is established here.

Product quality risks

• No independent published assay series of online mazdutide products was found.
• Indirect evidence: online semaglutide samples had 7%–14% purity and 29%–39% excess content; one had elevated endotoxin.
• FDA names this compound in warnings about unapproved research-labeled GLP-1 products of unknown quality.
• Wrong identity, wrong amount, contamination and counterfeit packaging are separate risks.