Weight Loss Injections: What's FDA-Approved, What's Not, and the Risks of Each
Weight loss injections include several FDA-approved GLP-1 receptor agonists, the dual GIP/GLP-1 agonist tirzepatide, and a growing range of compounded or research-grade peptides marketed online. The approved medicines carry boxed warnings and labelled risks. The unapproved injections lack regulator-reviewed human safety data. This page is a regulator-sourced overview, not medical advice.
FDA-approved weight-loss injections are Wegovy (semaglutide), Zepbound (tirzepatide), and Saxenda (liraglutide). They share a boxed warning for thyroid C-cell tumours and labelled risks for pancreatitis, kidney injury, gallbladder disease, and hypoglycaemia with insulin. Compounded or research-grade peptides sold as weight-loss injections are not FDA-approved and lack controlled human safety data.
Key Takeaways
- Three FDA-approved injectable medicines are indicated for chronic weight management: Wegovy (semaglutide), Zepbound (tirzepatide), and Saxenda (liraglutide).
- All three carry an FDA boxed warning for thyroid C-cell tumours and labelled warnings for pancreatitis, gallbladder disease, acute kidney injury, hypersensitivity, and hypoglycaemia with insulin or sulfonylureas.
- Mounjaro (tirzepatide) and Ozempic (semaglutide) are FDA-approved for type 2 diabetes, not weight management. Their use for weight loss is off-label.
- Compounded semaglutide and tirzepatide products have been the subject of FDA and TGA warnings about purity, dosing errors, and counterfeit ingredients.
- Research-grade peptides marketed as weight-loss injections (e.g. AOD-9604, MOTS-c, retatrutide) are not FDA-approved and are not characterised by controlled human safety data.
Which weight loss injections are FDA-approved?
Three injectable products are FDA-approved for chronic weight management as of mid-2026:
| Brand | Generic | Class | Approval |
|---|---|---|---|
| Wegovy | Semaglutide 2.4 mg weekly | GLP-1 receptor agonist | FDA-approved for chronic weight management; CV risk reduction in adults with CVD and obesity |
| Zepbound | Tirzepatide 5-15 mg weekly | Dual GIP/GLP-1 agonist | FDA-approved for chronic weight management |
| Saxenda | Liraglutide 3 mg daily | GLP-1 receptor agonist | FDA-approved for chronic weight management in adults and adolescents 12+ |
All three carry an FDA boxed warning for thyroid C-cell tumours based on rodent studies, and are contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia type 2 (MEN2). Read the per-drug FDA-label summaries linked above.
What about compounded semaglutide and tirzepatide?
During and after the supply shortages of branded semaglutide and tirzepatide, compounding pharmacies offered "compounded" versions. The FDA has issued multiple warning notices about compounded GLP-1 products, citing dosing errors, unverified active-ingredient identity, and counterfeit material. The TGA has issued similar warnings in Australia. The FDA position is that compounded versions of an FDA-approved drug are only appropriate when the approved drug is on the FDA shortage list, and even then with strict controls.
What about research-grade peptides marketed for weight loss?
A range of peptides marketed for weight loss are not FDA-approved and not regulator-reviewed for human use. They include:
- AOD-9604: fragment of the growth hormone molecule; failed phase II weight-loss trials.
- Retatrutide: an investigational triple GIP/GLP-1/glucagon agonist in late-stage trials. Not approved.
- MOTS-c: a mitochondrial-derived peptide. Not approved. WADA-prohibited.
- Tesamorelin (Egrifta): FDA-approved only for HIV-associated lipodystrophy. Off-label weight-loss use is not characterised by FDA-supported data.
These products are not pharmaceutical-grade. Their purity, potency, and sterility are not guaranteed. Speak to your doctor before considering any of them.
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Common Questions
As of 2026, three injectables are FDA-approved for chronic weight management: Wegovy (semaglutide 2.4 mg weekly), Zepbound (tirzepatide), and Saxenda (liraglutide 3 mg daily). Mounjaro and Ozempic are approved for type 2 diabetes, not weight loss, so weight-loss use of those products is off-label.
The FDA and TGA have issued public warnings about compounded GLP-1 products, citing dosing errors, unverified ingredients, and counterfeit material. Compounded versions of an approved drug are only intended for use when the approved drug is on the FDA shortage list, with strict controls. Discuss any compounded option with your doctor and pharmacist.
All three FDA-approved weight-loss injections (Wegovy, Zepbound, Saxenda) carry the same boxed warning for thyroid C-cell tumours, based on rodent studies. They are contraindicated in patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2.
Several peptides marketed for weight loss (e.g. AOD-9604, MOTS-c, retatrutide outside trials) are not FDA-approved. Their legal status depends on jurisdiction. Sale through unlicensed channels may be illegal. They are not regulator-supported therapeutics.
Per the FDA labels of Wegovy, Zepbound, and Saxenda, gastrointestinal symptoms dominate: nausea, vomiting, diarrhoea, constipation, abdominal pain. Serious labelled risks include pancreatitis, gallbladder disease, kidney injury, and hypersensitivity. See the per-drug pages for details.
References
- U.S. Food & Drug Administration. Wegovy (semaglutide) prescribing information. Source.
- U.S. Food & Drug Administration. Zepbound (tirzepatide) prescribing information. Source.
- U.S. Food & Drug Administration. Saxenda (liraglutide) prescribing information. Source.
- U.S. Food & Drug Administration. FDA warning on compounded semaglutide and tirzepatide. Source.
- Therapeutic Goods Administration (Australia). Compounded GLP-1 medicines. Source.