Does Wegovy make you tired?

Tiredness is a listed side effect. In the adult weight-reduction trials, fatigue or weakness was reported by 11% on Wegovy 2.4 mg versus 5% on placebo.

Does Zepbound cause fatigue?

Yes. In the weight-reduction trials, fatigue and related terms were reported by 5% to 7% depending on dose, against 3% on placebo.

Does Mounjaro cause fatigue?

The Mounjaro label reports fatigue in 10% of people in its heart outcomes trial, which compared it with dulaglutide. Fatigue is not in its main placebo table.

Could tiredness on a GLP-1 be low blood sugar?

It can be one cause. The leaflets list drowsiness, weakness and dizziness among low blood sugar signs and say the risk is higher with insulin or a sulfonylurea.

Fatigue on GLP-1 Medicines: What the Labels Report

Short answer: Yes, tiredness is a listed side effect. In the adult weight-loss trials, fatigue was reported by 11% on Wegovy 2.4 mg versus 5% on placebo, and 5% to 7% on Zepbound versus 3%. Mounjaro's heart outcomes trial reported fatigue in 10%. The labels do not explain why it happens. Some other listed side effects, such as low blood sugar, low blood pressure and dehydration, can also leave people feeling weak or drained.

What the labels report

Fatigue in trials, from each US label
Medicine and trials	On the medicine	Comparison
Wegovy 2.4 mg, adults, weight reduction	11%	5% on placebo
Wegovy 7.2 mg trials	11% on 7.2 mg, 9% on 2.4 mg	5% on placebo
Zepbound 5, 10 and 15 mg, weight reduction	5%, 6% and 7%	3% on placebo
Mounjaro, heart outcomes trial (SURPASS-CVOT)	10%	Trial compared against dulaglutide; label gives no comparison rate for fatigue
Ozempic, type 2 diabetes	Listed among other side effects above 0.4%	No rate given

The Wegovy figures count "fatigue and asthenia" (asthenia means weakness), and the Zepbound figures count asthenia, fatigue, lethargy and malaise together. The patient leaflets say "tiredness (fatigue)" for Wegovy and "feeling tired" for Zepbound.

The trials differ in who took part and for how long, and the labels say rates cannot be directly compared between drugs.

Other listed side effects that can feel like fatigue

The labels list several effects that overlap with feeling tired or weak. Telling them apart is a job for your provider, but knowing they exist helps you describe what you feel.

Low blood sugar. The leaflets list confusion or drowsiness, weakness, dizziness and headache among its signs, and say the risk is higher when the medicine is used with insulin or a sulfonylurea. See low blood sugar on GLP-1 medicines.
Low blood pressure. In the Zepbound weight-reduction trials, low blood pressure was reported in 1.6% versus 0.1% on placebo, more often in people on blood pressure medicines. In the Wegovy trials it was 1.3% versus 0.4%.
Dehydration. The labels say nausea, vomiting and diarrhea can cause fluid loss, and to tell your provider if those do not go away.

Timing and what the labels leave open

The labels do not say when fatigue tends to start, how long it lasts, or whether it is linked to eating less. They give stomach side effects a clear timing (mostly while the dose is being raised) but say nothing similar for tiredness.

That leaves room for many causes. Tiredness has plenty of explanations unrelated to the medicine, so a log that shows whether it follows your dose day or a dose increase, or appears no matter when you dose, is more useful to a prescriber than a general sense of being worn out.

What to note

Which days you feel tired, counted from your dose day, and whether it began after a dose increase.
Roughly how much you ate and drank that day, and any nausea, vomiting or diarrhea.
Blood sugar readings if you check them, especially if you also take insulin or a sulfonylurea.
Dizziness on standing, and any blood pressure readings.
Sleep, illness or other new medicines.

Dose Track lets you rate how you feel each day next to your dose log, so the pattern is easy to show at your next visit.

General education drawn from labels, public health agencies and published studies, not personal medical advice. Your prescriber, pharmacist and the label that came with your medicine are the final word. Questions for other users? Ask in the Dose Track community.

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