Tirzepatide vs Semaglutide
Full head-to-head comparison of tirzepatide and semaglutide: mechanism, trial data, dosing, side effects and cost.
Mechanism difference
Semaglutide is a single GLP-1 receptor agonist. Tirzepatide adds GIP receptor agonism, which improves insulin sensitivity and appears to blunt some GLP-1 side effects while increasing weight loss.
Weight-loss data
In pivotal trials, semaglutide 2.4 mg produced roughly 15% mean body-weight reduction at 68 weeks, while tirzepatide 15 mg reached roughly 21% at 72 weeks. Individual response varies widely.
Dosing and cost
Both are weekly subcutaneous injections with four-week titration steps. Cost depends heavily on insurance coverage and whether a compounded or branded product is used.
Frequently asked questions
Which produces more weight loss?
Trial data favours tirzepatide (about 21% at 15 mg over 72 weeks) over semaglutide (about 15% at 2.4 mg over 68 weeks).
Can you switch from semaglutide to tirzepatide?
Switching is common in practice; most protocols restart tirzepatide at 2.5 mg rather than matching the prior dose level.
Are side effects different?
Both cause dose-dependent GI effects. Nausea rates are broadly similar, with tirzepatide often reported as better tolerated at equivalent weight-loss levels.