Which Injectable GLP-1 is Best for Weight Loss?

Based on current clinical data, the answer depends on how you define “best.” For maximum average weight loss, tirzepatide (Zepbound) is the most effective injectable GLP-1 medication. However, semaglutide (Wegovy) remains a top choice with a strong, well-established efficacy and safety profile.

Tirzepatide (Zepbound): The Most Effective for Weight Loss

Tirzepatide is a dual GIP/GLP-1 receptor agonist, meaning it targets two hormones instead of one . This dual action is believed to contribute to its greater weight loss effects .

• Superior Head-to-Head Results: In the SURMOUNT-5 trial, which directly compared the two drugs at their maximum doses, tirzepatide produced significantly greater weight loss. Participants on tirzepatide lost an average of 20.2% of their body weight, compared to 13.7% for those on semaglutide .
• Highest Overall Efficacy: An updated network meta-analysis and a comprehensive systematic review both identified tirzepatide as producing the greatest placebo-subtracted weight loss among commercially available therapies, with reductions of up to -19.0% . It also showed the greatest reduction in fat mass in a separate analysis .

Semaglutide (Wegovy): A Powerful, Well-Established Option

Semaglutide is a GLP-1 receptor agonist that has been a leader in the weight loss space.

• Substantial Weight Loss: The standard 2.4 mg dose produces an average weight loss of about 15% . A higher dose (7.2 mg) has also been approved, offering the potential for greater weight loss .
• Additional Health Benefits: Unlike tirzepatide, semaglutide (Wegovy) is also FDA-approved to reduce the risk of major cardiovascular events in certain high-risk patients and to treat MASH (a serious liver disease) .
• Slight Ranking Variance: While one updated network meta-analysis ranked semaglutide 2.4 mg first by a very narrow margin over tirzepatide 15 mg (P-score 0.97 vs. 0.93), the authors noted that the head-to-head SURMOUNT-5 trial still demonstrated superior weight reduction with tirzepatide .

Other Injectable Options

• Liraglutide (Saxenda): This is an older GLP-1 medication. It is less effective than both semaglutide and tirzepatide, producing an average weight loss of 5-10% . It requires a daily injection, unlike the weekly injections for the others .

Summary Comparison

Ultimately, the “best” medication for you is a decision to be made with a healthcare provider, who can consider your specific health profile, goals, and tolerance for side effects.