Fatigue in each Ozempic® document
The three regulators describe the same molecule from overlapping trials, but each sets its own threshold for what goes in a table. That is why the US label has no fatigue percentage while the Canadian monograph does.
| Document and trial pool | Comparator | Ozempic® 0.5 mg | Ozempic® 1 mg |
|---|---|---|---|
| US label, placebo-controlled pool (section 6.1) [1] | not given | listed among reactions above 0.4% | listed among reactions above 0.4% |
| EU summary, section 4.8, phase 3a pool [2] | — | common (1 in 100 to 1 in 10) | common (1 in 100 to 1 in 10) |
| Canadian monograph, Table 2: 7 placebo- or active-controlled trials, fatigue and asthenia combined [3] | 1.4% | 2.6% | 3.3% |
What those numbers can and cannot tell you
The Canadian figures come from about 4,800 people across seven phase 3a trials of 30 or 52 weeks. The comparison group mixed placebo with three active diabetes medicines, and the percentages were adjusted for differences between trials [3]. Fatigue in that table also includes reports coded as asthenia, which means weakness or lack of strength.
The gap is real but small: roughly one or two extra people in every hundred reported tiredness on Ozempic®. None of the documents says when in treatment fatigue tended to appear, how long it lasted or whether it led anyone to stop. The Canadian monograph does say most nausea, vomiting and diarrhoea came during dose escalation and that people with lower body weight tended to have more stomach side effects [3].
Published reports on semaglutide and tiredness
Beyond the trial tables, published evidence on fatigue specifically with Ozempic® is limited. One 2025 case report describes a 74-year-old man with type 2 diabetes whose tiredness and walking endurance worsened over two years on semaglutide, during which he lost 8 kg and showed reduced muscle bulk and strength [4]. After other causes were ruled out, his doctors suspected muscle loss (sarcopenia) linked to the weight change; his fatigue improved after they reduced the semaglutide dose and started a strength-focused exercise programme.
A single case cannot show that a medicine causes a symptom or how often it happens. It does illustrate why clinicians may look at muscle strength and weight change, particularly in older adults, when tiredness persists.
Three ways Ozempic® could leave you tired
Low blood sugar, which the label documents. In the US monotherapy trial no severe low blood sugar occurred on Ozempic®, but section 5.5 warns that the risk rises when it is combined with a sulfonylurea or insulin [1]. In the US data, documented symptomatic low blood sugar occurred in 17.3% on 0.5 mg and 24.4% on 1 mg alongside a sulfonylurea [1]. The Medication Guide lists weakness, drowsiness, confusion and dizziness among the possible signs [1].
Fluid loss, which the label also documents. Section 5.6 describes kidney injury in people who became dehydrated after nausea, vomiting or diarrhoea, and the Medication Guide stresses drinking fluids [1]. Cleveland Clinic notes that dehydration itself can cause fatigue [6].
Eating less, a plausible link that has not been measured. Decreased appetite was reported in 6.3% on 0.5 mg and 7.2% on 1 mg against 2.0% on comparators in the Canadian pool [3]. Whether smaller meals explain any of the tiredness was not studied.
Other common causes
Fatigue is one of the least specific symptoms in medicine. MedlinePlus and Cleveland Clinic list many causes that are unrelated to Ozempic® [5][6]:
- Anaemia and iron deficiency, and low vitamin D or vitamin B12.
- An underactive or overactive thyroid.
- Sleep problems such as insomnia or obstructive sleep apnoea, and shift work.
- Depression, grief and ongoing stress.
- Other medicines, including sedatives, some antidepressants, antihistamines, blood pressure medicines, steroids and water pills.
- Infections, and long-term conditions including diabetes itself.
What general sources suggest
For fatigue without a medical cause, MedlinePlus suggests regular sleep, a balanced diet with enough fluids through the day, regular exercise, ways to relax, a manageable schedule and avoiding alcohol and nicotine [5]. It adds that caffeine and other stimulants do not treat fatigue and can make it worse when stopped, and that no medicine should be stopped or changed without first talking to a clinician.
Cleveland Clinic recommends seeing a clinician to rule out infections, vitamin deficiencies and other conditions, and talking through current medicines to see whether any of them could be responsible [6]. Neither source offers advice specific to Ozempic®, and the label does not describe a way to manage fatigue.
Ozempic® context for your notes
Ozempic® is injected once a week and is prescribed to adults with type 2 diabetes. Its label begins at 0.25 mg and raises the dose in steps of at least four weeks, up to 2 mg where needed [1]. Section 7.1 notes that a prescriber may consider lowering a sulfonylurea or insulin dose when Ozempic® is started, to reduce the chance of low blood sugar [1]. If tiredness appears around the start of treatment, a dose step or a change in your other diabetes medicines, those dates are worth recording.
Ozempic® is a registered trademark of Novo Nordisk A/S. PepLabo is not affiliated with or endorsed by Novo Nordisk.
When to get help
| Sign | Who to contact | How fast | Source |
|---|---|---|---|
| Tiredness with chest pain, shortness of breath, or a heartbeat that is unusually fast or slow | Emergency services | Emergency | Cleveland Clinic [6] |
| Confusion, fits or passing out, especially if you also use a sulfonylurea or insulin | Emergency services; these can be signs of severe low blood sugar | Emergency | Ozempic® Product Monograph [3] |
| Thoughts of harming yourself | Your provider or emergency services right away | Emergency | MedlinePlus [5] |
| Fatigue with very little urine, new swelling, or vomiting or diarrhoea that will not stop | Your prescriber, the same day | Today | Ozempic® Medication Guide [1], MedlinePlus [5] |
| Weakness, drowsiness, sweating or shakiness that keeps coming back | Your prescriber, to talk about low blood sugar | Today | Ozempic® Medication Guide [1] |
| Fatigue lasting more than a few days, starting suddenly, without a clear reason, or with weight loss | Your clinician | At your next appointment | Cleveland Clinic [6] |
