GLP-1 Fatigue: What the Labels Say About Feeling Tired

Short answer: Fatigue appears on the labels of Wegovy® (semaglutide), Zepbound® (tirzepatide) and Foundayo® (orforglipron). In weight-reduction trials, 11% of Wegovy patients reported it versus 5% on placebo, and the Zepbound and Foundayo labels list it too. Feeling tired has many possible causes, and the labels do not explain why it happened in the trials. This page reports the figures and what MedlinePlus says about fatigue. It cannot tell you why you feel tired.

How often was fatigue reported in trials?

These are the labels’ own figures from placebo-controlled weight-reduction trials, as listed on DailyMed on October 30, 2026. The trials differ in design, so do not compare them directly.

Label	Placebo	Treated patients
Wegovy injection (2.4 mg)	5%	11%
Zepbound (three strengths studied)	3%	5%, 6%, 7%
Foundayo (three strengths studied)	4%	6%, 7%, 9%

Treated figures run from the lowest strength studied to the highest. Wegovy’s table counts “fatigue and asthenia” (weakness) together. Your prescriber chooses what fits you.

Could tiredness be something else?

Quite possibly. MedlinePlus, the NIH patient-information site, defines fatigue as “a feeling of weariness, tiredness, or lack of energy” and lists many causes: certain medicines, not getting enough sleep, depression and anxiety, long-lasting diseases such as diabetes, and heart, liver, kidney and thyroid disease.

Two label topics are worth knowing about because they can overlap with feeling unwell:

• Low blood sugar. MedlinePlus lists drowsiness, weakness, dizziness, shakiness, sweating and hunger among the signs and symptoms of low blood sugar, which it describes in the semaglutide precautions. The Wegovy and Zepbound labels both say the medicine “lowers blood glucose and can cause hypoglycemia,” with a higher risk when it is used with insulin or insulin secretagogues such as sulfonylureas. Your prescriber manages that.
• Dehydration. The Wegovy and Zepbound labels say stomach and bowel reactions such as nausea, vomiting and diarrhea can lead to dehydration. See GLP-1 nausea and vomiting and GLP-1 constipation and diarrhea.

What does MedlinePlus say about when to get help for fatigue?

It says: “If you have been feeling tired for weeks, contact your health care provider.” It also says to call your provider if fatigue “does not get better after several weeks.”

How can you track how you feel?

A short note with each shot date and how your energy was that day, such as “slept badly” or “low energy,” helps your provider see whether tiredness lines up with anything else. Weeko, a shot tracker coming to iPhone and Android, is being built around that kind of simple log. It is a logbook, not medical guidance.

For the full list of effects, see GLP-1 side effects: a plain-language guide. For another effect that can show up during weight loss, see GLP-1 and hair loss.

When to call your doctor

Contact your health care provider if tiredness lasts for weeks, keeps getting worse, or comes with other symptoms. MedlinePlus says to call your doctor immediately for fainting or dizziness, a rapid or pounding heartbeat, decreased urination, or vision changes while using semaglutide. Do not stop or change a prescribed medicine on your own.