Best GLP-1 for weight loss

Which GLP-1 produced the most weight loss in a head-to-head trial?

Tirzepatide. SURMOUNT-5 randomized 751 adults with obesity but without type 2 diabetes to the maximum tolerated dose of tirzepatide (10 or 15 mg) or semaglutide (1.7 or 2.4 mg) once weekly for 72 weeks [1]. Mean weight change was 20.2% with tirzepatide versus 13.7% with semaglutide, and waist circumference fell 18.4 cm versus 13.0 cm [1]. The trial was open-label and funded by Eli Lilly, which makes tirzepatide, so the result is strong but not independent [1].

What did each drug show against placebo?

In SURMOUNT-1, 72 weeks of tirzepatide produced mean weight loss of 15.0% at 5 mg, 19.5% at 10 mg and 20.9% at 15 mg, versus 3.1% with placebo [2]. In STEP 1, 68 weeks of semaglutide 2.4 mg produced 14.9% weight loss versus 2.4% with placebo, and 86.4% of participants lost at least 5% of body weight [3]. The populations and durations differ, so these numbers should not be compared directly across trials.

Does "best" just mean the biggest number?

No. Foundayo, approved in 2026, is a once-daily tablet taken with or without food, which matters to people who will not inject [4]. Gastrointestinal side effects were the most common adverse events on both drugs in SURMOUNT-5, mostly during dose escalation [1]. Coverage, price and prior-authorization rules differ by drug and plan, so the best GLP-1 is often the one a person can tolerate, afford and stay on. See semaglutide vs tirzepatide for the mechanism differences.