Ozempic
Semaglutide · GLP-1 Agonist
FDA Approved (T2D)
GLP-1SemaglutideWeekly
Semaglutide by Novo Nordisk. GLP-1 receptor agonist -- suppresses appetite, slows gastric emptying, improves insulin secretion. Max dose 2mg weekly. FDA approved for T2D; widely used off-label for weight loss.
Semaglutide calculator →
Mounjaro
Tirzepatide · GLP-1 + GIP Dual Agonist
FDA Approved (T2D + Obesity)
GLP-1GIPTirzepatideWeekly
Tirzepatide by Eli Lilly. Dual GIP/GLP-1 agonist -- activates both receptors, enhancing fat oxidation in adipose tissue beyond GLP-1 alone. Max dose 15mg weekly. FDA approved for T2D (Mounjaro) and obesity (Zepbound).
Tirzepatide calculator →
Verdict
Mounjaro (tirzepatide) produces more weight loss than Ozempic (semaglutide) in every head-to-head comparison. The dual GIP + GLP-1 mechanism drives additional fat oxidation in adipose tissue that semaglutide alone cannot match. If maximum weight loss is the goal and you can tolerate either, tirzepatide wins. Ozempic has the advantage on cardiovascular outcomes data (SELECT trial showing 20% CV event reduction) and is more established for pure T2D glycemic control. For most weight loss-focused users, Mounjaro is the superior choice today.
Frequently Asked Questions
What is the difference between Ozempic and Mounjaro?
Ozempic is semaglutide (GLP-1 agonist only). Mounjaro is tirzepatide (GLP-1 + GIP dual agonist). The extra GIP activation enhances fat oxidation in adipose tissue and improves insulin sensitivity beyond what GLP-1 alone achieves, resulting in greater average weight loss.
Which causes more weight loss, Ozempic or Mounjaro?
Mounjaro. SURMOUNT-1 data shows tirzepatide at 15mg produces 22.5% body weight loss at 72 weeks. Semaglutide at comparable doses produces roughly 9--15%. The SURPASS-2 head-to-head confirmed tirzepatide superiority.
Does Mounjaro have worse side effects than Ozempic?
Side effect profiles are similar -- nausea, vomiting, diarrhea, constipation, especially at dose increases. Some data suggests tirzepatide feels slightly more tolerable. Both improve substantially after the first 4--8 weeks as the body adapts.
Can I switch from Ozempic to Mounjaro?
Yes. A common reason to switch is Ozempic response plateau. Start tirzepatide at a low dose (2.5mg) to re-establish GI tolerance, even if you were at higher semaglutide doses. Talk to your provider about the specific transition protocol.
Is Mounjaro approved for weight loss?
Yes. Tirzepatide received FDA approval for chronic weight management as Zepbound in November 2023. Mounjaro is the T2D branded name. Both contain tirzepatide at the same doses.