Evidence-graded answer
How long do GLP-1 side effects last?
Most GI side effects (nausea, constipation, reflux) peak in weeks 1-2 after each dose increase and resolve within 4 weeks. If you stay on a stable dose without further titration, side effects typically fade for ≥80% of patients by week 12.
Predictable pattern: side effects spike for 5-10 days after each dose step, then taper to baseline.
Persistent severe nausea past week 4 at maintenance dose is uncommon — talk to your prescriber about slower titration or dose reduction.
A small subset (~5-10%) cannot tolerate the maintenance dose long-term; switching molecules (semaglutide ↔ tirzepatide) resolves it for some.