Weight-loss drugs such as Wegovy and Zepbound have dominated headlines, yet roughly 17% of users see little or no benefit, prompting a search for alternatives. One experimental candidate, retatrutide, has already attracted attention despite lacking FDA approval.
What is retatrutide?
Retatrutide is a triple-agonist medication that targets three hormone receptors—GLP-1, GIP and glucagon—whereas Wegovy activates only GLP-1 and Zepbound engages GLP-1 and GIP. The added receptor activity is intended to boost weight-loss effects.
In phase-three trials, participants on the highest dose lost an average of 28.7% of their body weight over 68 weeks. By comparison, tirzepatide trials reported 15% to 22.5% loss over 72 weeks, and semaglutide studies showed 10% to 15% loss in a similar timeframe.
The drug is administered once a week by injection and works by curbing appetite and slowing digestion, mechanisms shared with other GLP-1 agents. Dr. Mir Ali of MemorialCare Surgical Weight Loss Center describes it as “the first one in the pipeline to work on three different receptors.”
Although Eli Lilly, the maker of both retatrutide and Zepbound, has not yet submitted trial data to the FDA, some online vendors are already offering the compound at reduced prices. These sources often involve compounding pharmacies preparing the medication without formal approval.
Dr. Ali says the drug is “not really available” outside clinical trials. There is no set timeline for when it will hit the market, given that clinical trial results have not yet been submitted to the FDA.
Physicians warn that the allure of a potent, unapproved drug can be dangerous. “People should wait to take medications until they are approved by the FDA to maximize safety,” says Dr. Richard Siegel, co-director of the Diabetes and Lipid Center at Tufts Medical Center.
Regulatory concerns
The FDA issued a press release in early February stating that selling retatrutide, or the related experimental drug cagrilintide, is illegal. The agency highlighted that these substances are not components of any FDA-approved product and have not been proven safe.
Following the announcement, the FDA sent warning letters to multiple companies that were distributing the drug without authorization. The agency’s statement noted that at least three firms received such letters.
Compounding pharmacies have become a gray area. While they can legally produce and sell their own versions of popular medications when FDA-approved versions are in shortage, the FDA clarified that once a medication is no longer in shortage, compounding it without approval violates federal law. Retatrutide and cagrilintide cannot be used in compounding under federal law.
Dr. Siegel adds that compounded drugs lack the rigorous oversight applied to approved medicines, raising the risk of inconsistent potency or contaminants. “While these medications may be safe, there is less oversight in their production,” he explains.
Dr. Ali cautions that patients could receive an unsafe or ineffective product. He recommends obtaining any medication through a qualified healthcare provider rather than an unverified source.
For individuals who have not responded to existing GLP-1 therapies, specialists suggest a wide-ranging approach that pairs medication with nutrition counseling, regular aerobic activity and resistance training.
Alternative solutions for non-responders
For individuals who have not responded to existing GLP-1 therapies, Dr. Ali recommends consulting an obesity medicine specialist. These specialists are more knowledgeable about various treatment options and can help patients find a suitable alternative.
