Does Wegovy make you tired?

Yes, Wegovy can make you feel tired. Fatigue is listed as a very common side effect in the official Wegovy product information, meaning it may affect more than 1 in 10 people taking the medication.

However, feeling tired while taking Wegovy doesn’t necessarily mean the medication itself is the only cause. Eating less, dehydration, changes in your blood sugar, and other lifestyle or health factors may also affect your energy levels.

In this guide, we’ll look at why Wegovy may make you tired, what you can do to manage fatigue, and when it’s worth speaking to a healthcare professional.

Why does Wegovy make you tired?

Fatigue is a recognised side effect of Wegovy, but there may be more than one reason why you feel tired during treatment. Changes to how much you’re eating, dehydration, and other side effects can all potentially affect your energy levels.

“If tiredness is affecting your day-to-day life, don’t assume you simply have to put up with it. Small changes to your diet, hydration, sleep, and activity may help, but speak to your clinical team if you’re concerned or it isn’t improving.”

Niya MansuriPrescribing Pharmacist

You may be eating less

Wegovy helps you feel fuller and less hungry, which can naturally lead to eating less. However, if your appetite drops significantly, you may find it more difficult to eat enough or get the nutrients your body needs.

Try to make the food you do eat count by choosing balanced, nutrient-dense meals where possible. If you’re struggling to eat enough, read our guide on how to eat when your appetite is low.

You may be dehydrated

Nausea, vomiting, and diarrhoea are common side effects of Wegovy and can cause dehydration. Dehydration is also listed as a potential complication of gastrointestinal side effects in the official Wegovy product information.

Dehydration can leave you feeling tired, so keeping on top of your fluid intake is important, particularly if you’re experiencing digestive side effects. Additionally, drinking water may also help you in your weight loss journey. Read our guide on the benefits of hydration for more information.

Other side effects may be affecting your energy

Feeling sick, vomiting, or experiencing other digestive symptoms can make it harder to eat and drink normally, which may contribute to feeling tired.

If nausea is affecting what you can eat or drink, our guide on how to stop feeling sick on Wegovy has practical advice for managing it.

Could blood sugar be making you feel tired on Wegovy?

If you have type 2 diabetes, low blood sugar (hypoglycaemia) could be another reason you feel tired. The Wegovy product information warns that the risk of hypoglycaemia is higher when Wegovy is used alongside insulin or certain other diabetes medicines.

Symptoms of low blood sugar can include:

• tiredness
• weakness
• dizziness
• sweating
• shaking
• difficulty concentrating
• feeling hungry

If you have diabetes and experience these symptoms, check your blood glucose if you’ve been advised to monitor it and follow the guidance given by your healthcare team.

Speak to your healthcare team if you’re experiencing repeated episodes of low blood sugar, as your diabetes medication may need to be reviewed.

How to manage tiredness on Wegovy

If Wegovy is making you feel tired, some simple changes to your diet and daily routine may help support your energy levels.

Prioritise nutrient-dense foods

When you’re eating less, it’s particularly important to make the most of the food you can manage. Aim for a balanced diet that includes nutrient-dense foods and enough protein to support your body while losing weight.

Our Wegovy diet guide goes in-depth into how and what to eat (or avoid) to feel your best while taking your medication.

Maintain good sleep habits

Tiredness isn’t always caused by Wegovy. Poor-quality sleep can also leave you feeling fatigued during the day. The HSE recommends keeping regular sleep and wake times and developing a consistent bedtime routine to support better sleep.

Keep moving where you can

Physical activity might feel less appealing when you’re tired, but staying active remains an important part of looking after your health while losing weight. Choose activities that feel manageable and build up gradually rather than pushing yourself when your energy levels are low.

Don’t take supplements without checking first

Low levels of nutrients such as iron or vitamin B12 can cause tiredness, but that doesn’t mean you should automatically take supplements if you feel fatigued. Speak to your healthcare team if you’re concerned about a nutritional deficiency, particularly if your tiredness is persistent. They can advise whether further assessment or supplementation is appropriate.

How long does tiredness from Wegovy last?

There’s no set timeframe for how long tiredness from Wegovy will last. However, the official Wegovy product information states that feeling weak or tired is mainly seen while your dose is being increased and usually improves over time. Side effects can affect everyone differently, and how you feel may also depend on other factors such as your diet, hydration, sleep, and overall health.

If your tiredness is mild, focus on eating well, staying hydrated, getting enough sleep, and keeping active where you can. If it persists, gets worse, or is affecting your everyday life, speak to your healthcare team. They can help determine whether Wegovy or something else may be contributing to how you feel.

When should you speak to a doctor about tiredness?

Feeling tired occasionally isn’t usually a cause for concern, but speak to your doctor or healthcare team if your fatigue:

• persists or continues to get worse
• is affecting your everyday life
• comes with other unexplained symptoms
• is accompanied by symptoms of low blood sugar if you have diabetes

Seek medical advice promptly if you’re struggling to eat or drink enough, particularly if you’re experiencing persistent vomiting or diarrhoea.

Tiredness can have many causes, including nutritional deficiencies and other medical conditions, so don’t assume that Wegovy is responsible if your symptoms are persistent or severe.

Get support with your Wegovy side effects

Side effects can be frustrating, particularly when they start to affect your everyday life. You can learn more about what to expect and how to manage common symptoms in our guide to Wegovy side effects.

And, if you’re struggling with tiredness or any other symptoms during treatment, you don’t have to manage them on your own. myBMI treatment plans include ongoing clinical support throughout your weight loss journey, including side effects support and medication.

Sources

• Wegovy Product Information. (2026) EMA. [Accessed 2 October 2026]
• Hypoglycaemia (hypos) - type 2 diabetes. (2024) HSE. [Accessed 2 October 2026]
• Sleep problems. (2025) HSE. [Accessed 2 October 2026]
• Iron deficiency anaemia. (2021) HSE. [Accessed 2 October 2026]
• Vitamin B12 or folate deficiency anaemia. (2024) HSE. [Accessed 2 October 2026]