Wegovy is FDA approved, which means FDA judged its benefits to outweigh its risks for the populations described on its label. It also carries a boxed warning, which is the strongest warning FDA applies.
Boxed warning: risk of thyroid C-cell tumors. In rodent studies, semaglutide caused thyroid C-cell tumors. It is not known whether it causes these tumors, including medullary thyroid carcinoma, in humans. Wegovy must not be used by anyone with a personal or family history of medullary thyroid carcinoma (MTC), or by anyone with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
Do not use Wegovy if you have had a serious allergic reaction to semaglutide or any of its ingredients, or if either boxed warning condition applies. Tell your prescriber if you are pregnant, planning pregnancy or breastfeeding.
Serious risks in the prescribing information include pancreatitis, gallbladder problems including gallstones, low blood sugar (particularly with insulin or a sulfonylurea), serious allergic reactions, acute kidney injury from dehydration, worsening of diabetic retinopathy in people with type 2 diabetes, increased heart rate, depression or thoughts of suicide, and food remaining in the stomach during general anesthesia or deep sedation, which you must disclose to any surgeon or anesthesiologist before a procedure.
The most common side effects are nausea, diarrhea, vomiting, constipation, abdominal pain, headache, fatigue, indigestion, dizziness, abdominal distension, burping, flatulence, gastroenteritis and heartburn (Novo Nordisk, Wegovy prescribing information). This is a summary, not the full label. Read the complete prescribing information and medication guide, and our Wegovy safety information.
Does Wegovy make you tired?
Yes, fatigue is a recognized side effect. It is listed among the common adverse reactions in the Wegovy prescribing information and was reported more often by participants taking semaglutide than by those on placebo. It is usually most noticeable in the first weeks and after each dose increase, and it usually eases.
The likely contributors are worth knowing because most of them are addressable: eating substantially less, which produces tiredness on its own; dehydration, because appetite suppression tends to reduce fluid intake as well as food intake; low protein intake, which is easy to slip into when you are not hungry; poor sleep from gastrointestinal symptoms, particularly reflux at night; and low blood sugar, which is mainly a risk if you also take insulin or a sulfonylurea.
Practical steps: keep fluids up deliberately rather than by thirst, prioritize protein in the meals you do eat, and do not cut calories below what your clinician has set. Fatigue that is severe, that does not improve after the first few weeks, or that comes with dizziness, a racing heart or shortness of breath should be reported to your clinician rather than absorbed.