Switching GLP-1s

Switching GLP-1s means moving from one of these medications to another — usually semaglutide to tirzepatide, occasionally the reverse, and increasingly between an injection and a tablet. People switch for three reasons: results have stalled, side effects are intolerable, or insurance changed its preferred product.

If the reason is results, there is now direct evidence. SURMOUNT-5 randomized 751 adults with obesity to tirzepatide or semaglutide for 72 weeks and found average weight change of −20.2% versus −13.7%. That is a meaningful gap, though it describes group averages, not a guarantee that any individual will do better after a switch.

The mechanics are the part people underestimate. There is no universal conversion table, because the drugs are not equipotent and the labels do not publish cross-brand equivalents. What the labels do specify is narrower and worth knowing: Wegovy’s label gives instructions for switching between its own injection and tablet forms, and states that patients on 2.4 mg injection may move to a specified tablet dose. The Rybelsus label warns that Rybelsus and Ozempic tablets — both oral semaglutide — are not substitutable on a milligram-to-milligram basis. If two forms of the same molecule need a conversion rule, so does a change of molecule.

The common mistake is assuming you resume at an equivalent dose. Most prescribers restart the new drug at or near its own starting dose and re-escalate, which means a temporary step backward in appetite control and a repeat of the early nausea. Expecting that in advance makes it tolerable.

Ask what starting dose the new drug will use, how long re-escalation will take, whether any overlap or gap is intended, and whether the switch needs a fresh prior authorization. Our brand-switch calculator and switching guide map the steps.