Triple Agonists (GLP-1/GIP/Glucagon): How to Select the Right Agent Within the Class

Is any triple agonist FDA-approved?

No. Retatrutide activates the GIP, GLP-1 and glucagon receptors and has been tested in a published Phase 2 trial [1], but no retatrutide product is FDA-approved. FDA states it cannot be used in compounding under federal law and has not been found safe and effective for any condition [2]. Compounded drugs are not reviewed by FDA for safety, effectiveness or quality [2].

So the practical question is not which triple agonist, but which approved drug fits the patient.

What the retatrutide trial showed

The trial was double-blind, randomized and placebo-controlled: 338 adults with obesity or overweight took weekly retatrutide 1, 4, 8 or 12 mg or placebo for 48 weeks [1]. At 48 weeks, mean weight change was -24.2% on 12 mg versus -2.1% on placebo, and 83% of the 12 mg group lost at least 15% versus 2% on placebo [1]. Gastrointestinal events were the most common adverse events, dose-related, and mostly mild to moderate [1]. The trial had no semaglutide or tirzepatide arm, so it does not rank retatrutide against any approved drug [1].

What the approved head-to-head data show

SURMOUNT-5 compared tirzepatide (10 or 15 mg) with semaglutide (1.7 or 2.4 mg) for 72 weeks in 751 adults with obesity and no diabetes: mean weight change was -20.2% versus -13.7%, and waist circumference fell 18.4 cm versus 13.0 cm [4].

SURPASS-2 compared tirzepatide 5, 10 and 15 mg with semaglutide 1 mg in 1,879 adults with type 2 diabetes over 40 weeks: HbA1c fell 2.01, 2.24 and 2.30 percentage points versus 1.86, and weight fell 1.9, 3.6 and 5.5 kg more than semaglutide [5].

Tirzepatide is labeled a GIP and GLP-1 receptor agonist, a dual agonist rather than a triple agonist [3].

What approved drugs offer on liver and heart outcomes

Wegovy injection holds an accelerated-approval indication for noncirrhotic MASH with moderate to advanced fibrosis (F2 to F3), based on improvement of MASH and fibrosis [6]. Separately, in SELECT, 17,604 adults with established cardiovascular disease and a BMI of 27 or higher but no diabetes were followed for a mean of 39.8 months; cardiovascular death, heart attack or stroke occurred in 6.5% on semaglutide 2.4 mg versus 8.0% on placebo (hazard ratio 0.80) [7].

Safety considerations for approved options

The Wegovy and Foundayo labels do not recommend use with another GLP-1 receptor agonist [6][8]. Retatrutide has no FDA-approved prescribing label [2].

The Wegovy label carries a boxed warning on rodent thyroid C-cell tumors, with human relevance unknown, and the Foundayo label carries a boxed warning with different wording (orforglipron was not pharmacologically active in rodents); both contraindicate the drug in people with a personal or family history of medullary thyroid carcinoma or MEN 2 [6][8]. Both labels also warn about acute pancreatitis, severe gastrointestinal reactions, kidney injury from volume depletion, gallbladder disease, and hypoglycemia with insulin or a sulfonylurea [6][8].

Bottom line

Nothing inside the triple-agonist class can be selected yet. The choice is between approved agents: tirzepatide where the head-to-head weight and HbA1c differences above matter [4][5]; Wegovy injection where its MASH indication is the point [6]; and semaglutide 2.4 mg where cardiovascular risk reduction is the point, based on SELECT [7].