Does Wegovy Make You Tired? GLP-1 Fatigue in the FDA Labels

Does Wegovy Make You Tired? Fatigue Rates by Drug, Dose and Trial

Each label prints fatigue as one row in its adverse reaction table. A reaction only makes a table if it clears that table's cut-off: for example, at least 2% and more common than placebo in Wegovy Table 3 and Zepbound Table 1, or at least 5% in Foundayo Table 1. Here is every row, with the population it came from.

Wegovy (Table 3 and Table 4)

In the three trials behind Table 3, 11% of adults on Wegovy 2.4 mg reported fatigue against 5% on placebo. The table's footnote reads "Includes fatigue and asthenia." Asthenia is the clinical word for weakness or lack of energy. The Wegovy Medication Guide also lists "tiredness (fatigue)" among the most common side effects.

Table 4 covers the newer 7.2 mg dose, from two 72-week trials that ran placebo, 2.4 mg and 7.2 mg arms side by side. Fatigue there was 5%, 9% and 11%. Table 4 has its own entry rule: a reaction is listed only if it was reported in at least 2% on 7.2 mg and more often than on both 2.4 mg and placebo, so every row in it shows 7.2 mg ahead. The table reports that gap; it does not test whether it is meaningful. The 9% for 2.4 mg in Table 4 and the 11% in Table 3 come from different groups of people, so the two figures don't contradict each other.

Zepbound (Table 1)

The Zepbound label pools Study 1 and Study 2: fatigue in 3% on placebo, then 5%, 6% and 7% at 5, 10 and 15 mg. Its footnote names four terms: asthenia, fatigue, lethargy and malaise. About a quarter of the pool had type 2 diabetes. One detail matters for reading the columns: Study 2 randomized only to 10 mg, 15 mg or placebo, so the 5 mg column comes from Study 1 alone. That makes the 5 mg figure a poor base for any dose trend. More on tirzepatide's wider profile is in the Zepbound side effects guide.

Foundayo (Table 1)

Foundayo, the once-daily orforglipron tablet, reports fatigue in 4% on placebo and 6%, 7% and 9% at 5.5, 9 and 17.2 mg across Trials 1 and 2. The footnote reads "Includes other related terms." Fatigue is also in the label's Highlights list of reactions seen in at least 5% of treated patients. The label notes the trials used an investigational orforglipron formulation, presented at equivalent Foundayo doses. Dose steps are covered in the Foundayo dosage chart.

Ozempic and Mounjaro

Neither diabetes brand has a placebo-controlled fatigue row. The Ozempic label lists fatigue, dysgeusia and dizziness among other adverse reactions with a frequency above 0.4%, with no percentage. The Mounjaro label mentions fatigue once, in a sentence about its cardiovascular outcomes trial: "In a CV outcomes trial of 6,647 adults with type 2 diabetes mellitus and established CV disease exposed to MOUNJARO, adverse reactions reported with MOUNJARO were similar with the exception of dysesthesia (0.7%), decreased appetite (17%), constipation (13%), vomiting (12%), abdominal pain (10%), and fatigue (10%)." That sentence has no comparator, and fatigue is not a row in Mounjaro's Table 1, so the 10% should not sit next to Zepbound's numbers. The NHS lists feeling tired among the common side effects of both semaglutide and tirzepatide.

How to Read These Numbers

Prescribing information carries a standard caution that adverse reaction rates from one drug's trials can't be directly compared with rates from another drug's trials. These three tables show why. The share of people with type 2 diabetes differs (19%, 25% and 31%), the treatment periods differ (up to 68 weeks versus up to 72), and each label bundles different terms into its fatigue row.

The gap over placebo can still be stated as plain arithmetic: 6 percentage points for Wegovy 2.4 mg in Table 3, 4 for Zepbound 15 mg, and 5 for Foundayo 17.2 mg. Don't read those gaps as a ranking; each comes from its own set of trials. For the Wegovy pill, the label says the common adverse reactions in the 25 mg tablet trial were similar in type and frequency to Table 3, and it gives no separate tablet fatigue rate. The Wegovy pill side effects page covers that tablet trial in detail.

What the Labels Do Not Say About GLP-1 Fatigue

The labels count. They don't explain. In the Wegovy label, fatigue appears in four places: the Highlights list of reactions at 5% or more, Table 3, Table 4 and the Medication Guide. None of those gives an onset, a duration or a cause. The Zepbound label gives the rate in Table 1 with its footnote, lists fatigue in Highlights, and its Patient Information names "feeling tired" among the most common side effects. None of those gives an onset, a duration or a cause either. The Ozempic label gives no fatigue rate, only a frequency threshold of above 0.4%.

So questions people often search, such as how long it lasts and whether it fades, are not answered by any of these documents. That gap is about what labels cover. It tells you nothing either way about how long tiredness lasts.

Clinical experience fills some of the gap. It's opinion, though, not trial evidence. In the video below, obesity physician Dr. Spencer Nadolsky says no one knows the exact mechanism. He describes patients who feel tired without eating less or losing weight. For some it eases over time; others feel it for a day or two after each weekly shot. His explanations for why are hypotheses, and this page doesn't treat them as facts.

A physician's view, not trial data. Dr. Spencer Nadolsky covers fatigue as the fifth of five GLP-1 side effects; the video starts at that segment.

Label-Documented Problems Worth Checking

Neither the Wegovy nor the Zepbound label lists tiredness as a sign of kidney injury. For low blood sugar, the Wegovy Medication Guide and the Zepbound Patient Information list signs that include weakness and confusion or drowsiness, along with dizziness, sweating, shakiness and hunger. Both issues are documented in the labels, so both are fair to raise when tiredness shows up.

Dehydration After Nausea, Vomiting or Diarrhea

Both the Wegovy label (section 5.5) and the Zepbound label (section 5.3) carry an acute kidney injury warning. Each says most of the reported cases happened in patients whose nausea, vomiting or diarrhea led to dehydration. Prescribers are told to monitor kidney function in patients reporting reactions that could deplete fluids, especially while the dose is being started and raised. The practical point: if gut side effects are keeping fluids down, that is already a reason to call. Practical steps for nausea are in our semaglutide nausea guide.

Low Blood Sugar With Insulin or a Sulfonylurea

The Wegovy (section 5.4) and Zepbound (section 5.7) labels both warn that taking them with insulin or an insulin secretagogue, such as a sulfonylurea, may raise the risk of hypoglycemia, including severe hypoglycemia. Wegovy's Table 3 lists hypoglycemia at 6% versus 2% on placebo in one trial of adults with type 2 diabetes not on insulin (Study 3). In Zepbound's type 2 diabetes trial (Study 2), it was 4.2% versus 1.3%, and 10.3% in people also on a sulfonylurea against 2.1% in those who weren't. In Study 1, which enrolled people without diabetes, 0.3% had a reading below 54 mg/dL, though the label says hypoglycemia wasn't systematically captured there. None of this means low blood sugar explains the tiredness. It is a checkable possibility, mainly for people with diabetes.

Tiredness With Hair Shedding, and Lab Work

Tiredness that arrives alongside hair shedding is covered in does semaglutide cause hair loss, and the GLP-1 blood work guide explains what the labels do and don't ask for in testing.

A Counterpoint: Tirzepatide in Sleep Apnea

One group runs against the tiredness story. A 2026 post-hoc analysis of SURMOUNT-OSA, which enrolled adults with obesity and moderate-to-severe obstructive sleep apnea, found tirzepatide was associated with greater improvements than placebo on patient-reported outcomes. In Study 1, tirzepatide-treated participants who were fatigued at baseline had a numerically larger SF-36v2 Vitality improvement over placebo than those who were not.

Read that narrowly. The authors include Eli Lilly employees, the analysis was post hoc, and everyone in it had sleep apnea, so the result says nothing about people without it. It is not an analysis of fatigue as a side effect. Context on the trial is in our tirzepatide sleep apnea page and the tirzepatide hub.

When to Talk to Your Prescriber About Wegovy Fatigue

Ordinary tiredness and a warning sign can feel alike. These are the situations that point to a call rather than waiting:

Dose changes, pauses and supplements are your prescriber's decision. Retatrutide is still investigational and is not covered on this page; the retatrutide half-life guide covers its trial data. People also trade experiences online, collected in our semaglutide Reddit roundup.