GLP-3 is one of the most searched terms in weight loss right now, and the name is a nickname rather than an official drug class. There is no GLP-3 receptor. The term attached itself to retatrutide, a once-weekly injection that mimics three naturally occurring hormones involved in appetite, blood sugar, and energy use. A great deal of what is written about it online comes from sellers rather than clinicians, and Body Works would rather you get the accurate version from a provider in Franklin or Nolensville.
When people search for GLP-3, they are almost always describing retatrutide. The nickname followed a logical-looking pattern: if semaglutide acts on one receptor and tirzepatide acts on two, then the compound acting on three must be the third generation. The naming is intuitive and it is not how drug classification works.
Retatrutide is a triple agonist. It acts on the GIP receptor, the GLP-1 receptor, and the glucagon receptor. Note that GLP-1 is genuinely one of its three pathways, which is part of why the numbering confusion persists. There is no receptor called GLP-3 involved anywhere in its mechanism.
The interest in the compound people call a GLP-3 comes from that third target. GIP and GLP-1 agonism work largely through appetite regulation, insulin response, and gastric emptying. Glucagon receptor agonism is different: it is associated with increased energy expenditure, meaning the potential to affect the output side of the equation rather than only intake.
That is a genuinely different mechanism from what current approved medications do, and it is why the compound has drawn so much clinical attention. It is also why it should be discussed carefully. A more powerful set of mechanisms is not automatically a better fit for an individual patient.
Early studies suggest weekly retatrutide (GLP-3) injections can reduce cravings, assist with appetite control, and curb general hunger. It mimics three naturally occurring hormones involved in appetite, blood sugar, and energy use, which lets patients feel full sooner by slowing stomach emptying while the added glucagon activity is associated with higher energy expenditure. In the 48-week phase 2 trial in the New England Journal of Medicine, participants on the highest dose lost an average of 24.2% of their body weight, and the first phase 3 results, published in The Lancet in June 2026, showed 11.5% to 15.3% weight loss over 40 weeks in adults with type 2 diabetes.
In the latest trials, the most common side effects are gastrointestinal: bloating, loose stool, nausea, and vomiting. An increase in resting heart rate has also been noted. These symptoms are typically mild to moderate, are dose-related, and were eased in the phase 2 trial by starting at a lower dose. Only 2% to 5% of phase 3 participants stopped treatment because of side effects.
Curious how retatrutide (GLP-3) could work for you on your weight loss journey? Schedule a Free Consultation to meet with one of our medical providers. Weight loss care at Body Works differs from other Middle Tennessee weight loss clinics: we pair the medication with patient education, written nutrition and symptom guidance, and dose adjustments made by a physician who is watching your progress, because that combination is what produces lasting results.
Please note that the FDA has not yet approved retatrutide for medical use; it remains in the lengthy clinical trial and approval process. Body Works is fully committed to providing our patients with alternatives should we not be able to offer these weight loss injections in the future. If a previous medication stalled or was not tolerated, that is a conversation worth having now. Read how switching from tirzepatide to retatrutide is timed and dosed, or start with the retatrutide (GLP-3) therapy page.
Patients and providers most often turn to retatrutide (GLP-3) for these benefits:
Individual results vary. Ask your provider whether retatrutide (GLP-3) fits your goals and health history.
Explore the full peptide therapy and medical weight loss programs at Body Works in Franklin and Nolensville, including retatrutide (GLP-3) in Franklin, retatrutide (GLP-3) in Nolensville, and retatrutide (GLP-3) for Nashville patients.
Body Works Franklin
1113 Murfreesboro Rd Suite 307
Franklin, TN 37064
(615) 790-2548
By appointment Monday through Friday
Body Works Nolensville
210 Burkitt Commons Ave
Nolensville, TN 37135
(615) 941-1000
By appointment Monday through Friday
GLP-3 is an informal nickname rather than an official medical or regulatory drug class. There is no GLP-3 receptor. The term is used online to describe retatrutide, an investigational compound that acts on three receptors: GIP, GLP-1, and glucagon.
The nickname refers to retatrutide, yes, but the name itself is inaccurate. Retatrutide is a triple agonist targeting GIP, GLP-1, and glucagon receptors. GLP-1 is genuinely one of its three pathways, which is part of why the numbering confusion took hold.
The difference is the number of pathways and, more importantly, which ones. GLP-1 medications such as semaglutide work through appetite regulation, insulin response, and gastric emptying. The compound called a GLP-3 adds glucagon receptor agonism, which is associated with increased energy expenditure rather than reduced intake alone.
Not yet. Retatrutide, the compound the nickname refers to, is still in the clinical trial and approval process, with phase 3 results now being published. Body Works is committed to providing patients with supervised alternatives should these injections not be available in the future. Be cautious of any online seller offering a product under the GLP-3 name.
Bring it to a consultation. A provider at Body Works in Franklin or Nolensville will review your history, your goals, and any medication you are already on, and build the plan from there. If you are on tirzepatide and have plateaued, the guide to switching from tirzepatide to retatrutide covers how the change is timed.
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