An experimental weight loss drug, known as retatrutide or "Triple G," is being made available to a limited number of patients before its official U.S. Food and Drug Administration (FDA) approval. The drug mimics three hormones involved in appetite and metabolism – GLP-1, GIP, and glucagon – a mechanism that has led to substantial weight loss in clinical trials.
In a study lasting 80 weeks, participants taking retatrutide lost up to 28% of their body weight. Some individuals experienced such rapid and significant weight loss that they withdrew from the trial. For comparison, semaglutide (Ozempic, Wegovy) mimics one hormone and has shown roughly 15% weight loss, while tirzepatide (Mounjaro, Zepbound) mimics two hormones and can result in around 20% weight loss.
In addition to weight loss, the latest trial data for retatrutide indicated a reduction in A1C levels by up to 1.6%, suggesting benefits for individuals with type 2 diabetes. Eli Lilly, the drug's manufacturer, stated that a primary goal for retatrutide is to help patients with type 2 diabetes improve blood sugar control and lose weight, addressing the historical difficulty in treating obesity in this population.
Eli Lilly plans to submit retatrutide for FDA approval in early 2027. The FDA's review process typically takes up to a year, meaning the drug could be available on the market by late 2027 at the earliest.
In the interim, Eli Lilly is expanding access to the drug through its “compassionate use” program. This program allows certain patients with serious or life-threatening conditions to access investigational drugs outside of clinical trials. Following media reports of a patient receiving the drug through this program, the company has provided more specific, though still vague, eligibility criteria. Eligible patients must be 18 or older, have refractory obesity despite maximal approved obesity therapies, have at least two serious or life-threatening obesity-related complications, and be unable to participate in ongoing clinical trials.
Refractory obesity is defined as the inability to lose and maintain more than 5% of body weight despite treatment with the highest approved doses of weight loss medications. However, the company has not specified which obesity-related complications would qualify, leaving some doctors seeking further clarification.
Doctors must submit requests to Eli Lilly on behalf of eligible patients, and the company states it is actively reviewing these submissions.
Regulatory and Classification Disputes
Eli Lilly is also engaged in a dispute with the FDA regarding the classification of retatrutide. The company advocates for the drug to be classified as a biologic, which would provide 12 years of market exclusivity. The FDA, however, views it as a peptide, which would grant only five years of protection. A biologic classification would also present greater obstacles for compounding pharmacies to create alternative versions of the drug, a concern given that approximately 1.5 million people use compounded versions of GLP-1 medications.
The debate occurs as unverified versions of retatrutide are already being sold online by peptide companies. These products are often labeled for research purposes only and lack verified content, potency, and purity. Reports indicate that at least 14 individuals have been hospitalized after using these unregulated versions of retatrutide.