Does Wegovy Make You Tired? Why It Happens and What Helps (UK)

Is tiredness a side effect of Wegovy? What the leaflet says

Yes. The UK leaflet for Wegovy FlexTouch lists “feeling weak or tired” among the very common side effects (more than 1 in 10 people), along with headache, nausea, vomiting, diarrhoea, constipation and stomach pain, and says these usually go away over time. The prescribing information adds that fatigue was mainly seen during the dose-escalation period. The NHS also lists feeling tired as a common side effect of semaglutide.

Other listed side effects can drain your energy too:

Wegovy vs Mounjaro: which makes you more tired?

On paper, Wegovy. Its leaflet puts feeling weak or tired in the very common group (more than 1 in 10), while the Mounjaro leaflet lists fatigue as common (up to 1 in 10) for weight management. These come from separate trials, so it isn’t a head-to-head comparison, and many people on either medicine feel fine. See does Mounjaro make you tired?

Why Wegovy can make you tired

The leaflet doesn’t give one cause. The likely contributors:

• Eating a lot less. Wegovy acts on appetite areas in the brain so you feel fuller and less hungry. Fewer calories can mean less energy, especially if meals become very small. See tired after eating if the slump comes after meals.
• Dehydration. The leaflet warns that nausea, vomiting and diarrhoea can cause loss of fluids and says to drink enough to prevent it. The NHS lists feeling tired and dizzy among the signs of dehydration.
• Low blood sugar. The risk is higher if you also take a sulfonylurea (such as gliclazide) or insulin. The leaflet lists feeling sleepy or weak, sweating, shaking and confusion as warning signs.
• Dizziness and low blood pressure. Some people feel dizzy, mainly in the first 3 months.
• Poor sleep. Night-time nausea or reflux can break up your nights. See can’t sleep on Mounjaro or Wegovy? and sleep and weight loss.
• Nutrient gaps and muscle loss. A 2025 joint advisory from four US nutrition and obesity societies lists nutrient deficiencies from eating less, and loss of muscle and bone, among the challenges of GLP-1 treatment.

Everyday causes still count too: see why am I always tired?

How long does Wegovy tiredness last?

For most people it’s temporary. The leaflet says the very common side effects, feeling weak or tired included, usually go away over time, and the prescribing information says fatigue was mainly seen while the dose was being increased. So expect it most in the first weeks and for a while after each step up.

Tired the day after the injection?

Some people notice a dip in the day or two after their weekly dose, often with nausea, though the leaflet doesn’t describe this pattern. Keep a short diary of injection day, meals, fluids and energy to share with your prescriber. The NHS says you can change your injection day as long as it’s been at least 3 days since your last injection, so ask whether a different day would suit your week.

If you’ve been tired for a few weeks and it isn’t improving, or it affects daily life, the NHS advises seeing a GP.

What helps tiredness on Wegovy

1. Eat regular small meals, even when you’re not hungry, built around protein, vegetables and whole grains, and follow any diet advice from your prescriber or dietitian. See how much protein do I need?
2. Drink enough fluids, little and often if you feel sick. See how much water should I drink? and electrolytes.
3. Skip alcohol. The NHS says it’s best not to drink on semaglutide because it can make feeling or being sick worse.
4. Keep moving. The advisory recommends strength training to help protect muscle while you lose weight. A short walk can lift an afternoon dip: see afternoon slump.
5. Protect your sleep: regular bed and wake times, and no late caffeine.
6. Ask about blood tests if tiredness lasts. Signs of low iron, vitamin B12 or vitamin D are in our guides to iron deficiency, vitamin B12 deficiency and vitamin D deficiency.
7. Never change or stop your dose on your own. The leaflet says not to stop Wegovy without talking to your doctor.

When to get advice or urgent help

Severe, persistent stomach pain can be a sign of acute pancreatitis, which the leaflet calls serious and potentially life-threatening. If you think you’re having a serious side effect, the NHS says to call 111. You can report side effects through the MHRA Yellow Card scheme.

Pregnancy: the NHS says semaglutide isn’t used in pregnancy or while breastfeeding, and to stop it at least 2 months before trying for a baby. We don’t recommend our products during pregnancy or breastfeeding.

Supplements on Wegovy: check first

No supplement treats Wegovy side effects. The NHS asks you to tell your doctor or pharmacist about any herbal remedies, vitamins or supplements before you use semaglutide, so check with your GP or pharmacist before adding anything. See magnesium on Mounjaro or Wegovy and magnesium and weight loss.

Our pick

Magnesium Glycinate Sleep Complex

Magnesium Glycinate Sleep Complex is a berry drink powder with 290mg of magnesium (77% NRV) per 4.75g serving, from bisglycinate and citrate, plus glycine and L-theanine. Magnesium contributes to a reduction of tiredness and fatigue. It doesn’t override a medicine side effect, so ask your pharmacist first and how far apart to take it from other medicines.

Add Magnesium Glycinate Sleep Complex to bag See ingredients and reviews

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• Reishi Mushroom Adaptogenic Complex is a reishi hot chocolate: per 8g serving, 0.5g reishi, 0.5g maca and 0.3g cinnamon with cacao. It contains a little natural caffeine, so have it before mid-afternoon.
• Sleep CBD Oil is our evening oil: broad spectrum CBD with 70mg of passionflower extract per half pipette. On the 500mg bottle, half a pipette (0.35ml) gives 17.5mg of CBD; about 0.2ml on the 500mg (0.1ml on the 1,000mg) gives 10mg. The FSA advises people taking any medication not to take CBD unless under medical direction, so speak to your prescriber first.

The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.

iIf you take any regular medicines, check with your GP or pharmacist first. We don’t recommend our products during pregnancy or breastfeeding. All three are vegan, made in the UK and for adults (18+) only.