Almost everyone gets something in the first weeks after each dose increase. Most of it fades in 2–4 weeks. A small set of symptoms should never be waited out.
| Side effect (trial rate, drug vs placebo) | Wegovy 2.4 mg | Zepbound 15 mg | Saxenda 3.0 mg |
|---|---|---|---|
| Nausea | 44% vs 17% | 31% vs 10% | 40% vs 15% |
| Diarrhea | 32% vs 16% | 23% vs 7% | 21% vs 9% |
| Vomiting | 25% vs 7% | 12% vs 2% | 16% vs 4% |
| Constipation | 23% vs 10% | 12% vs 6% | 20% vs 9% |
| Stopped drug because of side effects | 7% vs 3% | 6% vs 3% | 10% vs 4% |
| Gallbladder events | 2.6% vs 1.2% | ≈1% | ≈2–3% |
STEP 1, SURMOUNT-1, SCALE. Oral semaglutide 25 mg shows the same pattern as the injection. Rates are from separate placebo-controlled trials, not head-to-head.
Food timing and size. Four or five small meals beats three normal ones. Protein first on the plate. Fluids between meals rather than with them.
Injection timing. Many people inject in the evening so the peak nausea window overlaps with sleep. Same day each week; a missed weekly dose can be taken within 4 days (Wegovy) or 4 days (Zepbound), otherwise skip — check your label.
Constipation kit. Psyllium or a fibre supplement, magnesium citrate at night, and an actual walk. If nothing for 3+ days, tell your prescriber; osmotic laxatives are commonly used.
Nausea kit. Ginger, small bland carbs (crackers, toast), cold food smells less. Prescribers sometimes add an anti-nausea medication for the titration weeks.
Dehydration is the sneaky one. Less hunger means less thirst cue and less water from food. Headache and fatigue on a GLP-1 are usually fluid before anything else.
Before surgery or a procedure under sedation, tell the anaesthetist you are on a GLP-1; slowed stomach emptying changes the fasting rules.
Personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia type 2. Pregnancy, and planning pregnancy within about 2 months (stop before trying). Prior serious reaction to the drug class.
Use with extra caution and a real conversation: history of pancreatitis, gallbladder disease, gastroparesis or severe GI disease, diabetic retinopathy, kidney impairment, and anyone with a history of an eating disorder.