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Yes, ~10-15% of users report fatigue, especially first 4-8 weeks. Causes: reduced caloric intake, GI side effects, sleep disruption from nausea. Usually resolves by month 3.
Fatigue on Wegovy is common — 10-15% of users in STEP-1 trial. Mechanisms: (1) Reduced caloric intake (often -500 to -1000 kcal/day) during titration leaves body without usual energy supply. (2) GI side effects disrupt sleep. (3) Dehydration from reduced food/water intake. (4) Possibly direct GLP-1 effect on sleep architecture. Timing: peaks weeks 1-4, resolves by month 3 for most. Mitigation: adequate protein (1.4g/kg/day), iron + B12 + vitamin D check if persistent, electrolyte awareness (sodium loss), slower titration if severe. Persistent fatigue past month 3: rule out anemia, thyroid changes, sleep apnea.
Editorial answer reviewed by a board-certified clinician. Not medical advice. Coordinate treatment decisions with your prescriber.