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Does Wegovy (semaglutide) make you tired?

Tiredness on weight loss injections like Wegovy is pretty common. Here’s why it happens and how you can try to relieve it.

iconPublished: 24th March 2025
Research-Based Guide

Have you noticed that since starting Wegovy weight loss injections, you feel more tired than usual? It’s not just you—tiredness is a pretty common side effect of the medicine. Usually though, it’s nothing serious and goes away on its own.

We don’t know exactly why Wegovy, which uses the active ingredient semaglutide, causes fatigue. But from what we know about how the medicine works, there are a few possible explanations.

So if you’re wondering why you’re suddenly so exhausted on Wegovy (and want to know what you can do about it) read on. We’ve laid it all out below.

Can semaglutide cause fatigue?

Yes, it can. In fact, tiredness is one of the most commonly reported side effects.

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How common is fatigue on Wegovy?

Roughly, it’s estimated that over one in 10 people will experience fatigue while on Wegovy.

In three clinical trials that included a total of 2,116 people using Wegovy for weight loss, around 11% reported fatigue or feeling weak.

Why does taking semaglutide make you tired?

We don’t have enough scientific evidence to say for sure. Though based on what we know about how Wegovy acts on the body, there are a few possible reasons.

Your blood sugar is too low (hypoglycaemia)

One way that Wegovy works is by increasing your insulin levels when you eat. This signals to the brain that you’re full and keeps your blood sugar levels in check. But if you are also using another medicine that controls your blood sugar, these effects could combine and your levels might dip too low. This can make you feel tired.

You’re eating less

Wegovy is an appetite suppressant: stimulating insulin production is one way it makes you feel full. It also slows your digestion and keeps your cravings at bay.

That means you eat less (and, therefore, lose weight). But when you take in less calories, you might feel more fatigued.

You aren’t drinking enough water

If you don’t drink enough water to top up the fluids lost, you can get dehydrated—which can make you tired.

You’re losing muscle

When you lose weight, you don’t necessarily just lose fat. You might also lose water or muscle—and it’s the latter that you want to try and avoid.

Among other things, losing muscle can disrupt your metabolism and reduce the amount of energy your body uses. And this can bring on fatigue.

Eating enough protein, strength training regularly, and losing weight gradually rather than quickly (for example, through a crash diet) can all help to preserve muscle.

Your symptoms are messing with your sleep

Other side effects of Wegovy, including constipation, diarrhoea, nausea, and stomach pain, can all make it difficult to get a good night’s sleep.

How long does fatigue last on semaglutide?

If you’re reading this through Wegovy tiredness—we see you. And we want to reassure you that symptoms typically clear up over time. 

FYI: side effects tend to come on when you either just start Wegovy or increase your dose. And they usually go away as your body gets used to the medicine.

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Learn more about Wegovy as a weight loss treatment to make an informed decision.
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Science backed programme
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Personalised support
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Trusted by 65,000 customers across the UK

How to manage fatigue on semaglutide?

There are plenty of ways to boost your energy levels while taking Wegovy.

Get a good night’s rest

We’re starting off with the most obvious piece of advice: get a good night’s sleep. It’s recommended that you get between 7-9 hours each night. Here, it’s all about building a relaxing bedtime routine and sticking with it. For example, try to go to bed at the same time each night and do something calming beforehand that will help you wind down. It’s easier to fall asleep when it’s dark, quiet, and cool—so you might try wearing earplugs or an eye mask (we’re personally fans of both).

Build healthy habits

Taking good care of your body can help you feel more energised.

That includes making sure your diet has enough essential nutrients to keep your body working at its best. Reaching for foods that break down more gradually in the body, like wholegrain foods, can also provide you with a steadier supply of energy compared to foods that break down fast (like refined carbs) and give you an energy rush.

And don’t forget to work out. Exercising regularly can improve your metabolism and increase the amount of energy your body uses. Not to mention dampen stress, which might in turn make it easier to sleep. It’s recommended that you do two strength sessions and 150 minutes of moderate-intensity exercise each week.

Get to a healthy weight

When you reach a healthy weight, your metabolism improves and your body learns to use energy more efficiently, which can help tackle your tiredness.

Plus, healthy weight loss can help you get better sleep and improve your mood.

When to see a doctor

Feeling tired sometimes is totally normal. Though if you’re tired all the time, your fatigue isn’t going away or getting better, or if your tiredness is affecting your day-to-day life, it’s a good idea to speak with your doctor.

If you have other symptoms as well, such as mood changes or if you’ve been told that you’re making choking or gasping noises while sleeping, that’s also a reason to get checked—as these are not common side effects of Wegovy.

Sometimes, tiredness might be a sign of another medical condition, such as anemia. Your provider will know what to look for and can help you get to the bottom of what’s going on.

Your weight loss journey

Feeling tired on Wegovy certainly isn’t fun, but in most cases, it’s nothing serious and will clear up.

Through our weight loss programme, our team of clinicians and coaches will be on hand to answer all your questions, including about side effects, staying motivated, and how to build lifestyle habits that stick. We know it can be scary to take the leap and try something new—but we’re here for you, and we know you’ve got this.

We’ll also post weight loss medication to you each month. Take our short quiz to see if you’re eligible, it won’t take more than five minutes.

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FAQ

FAQ: Does semaglutide make you tired?

Dr Earim Chaudry, MBBS
DisclaimerAt Voy, we ensure that everything you read in our blog is medically reviewed and approved. However, the information provided is not meant to replace professional medical advice, diagnosis, or treatment. It should not be relied upon for specific medical advice.
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