Wegovy vs Mounjaro and Sleep

Posted on October 16, 2026 by Sally-Anne Turner

What You Need To Know When Starting GLP-1s

Let’s talk about sleep.

Sleep is something that everyone does each day. On average, a person will spend 9,496 days of their life sleeping.

Why do we sleep? That’s not exactly clear. However, if you have ever had insomnia or been sleep-deprived, you will know the awful feelings that can come with that. Irritability, difficulty concentrating and even physical symptoms like headaches and abdominal pain become more common.

So, if you are looking to start your weight loss journey with a GLP-1 like Mounjaro UK, you may be worried about the stories of sleep issues that come with them. This goes beyond a simple Wegovy vs Mounjaro comparison and makes this process more daunting. Especially if you have a mental health issue or a gastrointestinal issue, which may already impact your sleep.

If you already have sleep-related issues, you will need clinical oversight to keep your sleep hygiene in top condition. At the Bodyline Clinic, our dedicated clinical team can help you get those much-needed 40 winks a night, while also helping you to lose weight using one of our GLP-1 medications. With nearly 20 years of experience, we know what it takes to keep your health in top shape as you hit your weight loss goals.

Here, we will look at how taking either of these GLP-1’s may impact your sleep and how our team can help you manage those symptoms.

Why is Sleep Important?

We can run through this quickly.

According to the Sleep Foundation, sleep is important as it supports brain function, helps to regulate hormones, restores the body and helps to maintain overall health and wellbeing.

Worryingly, there are estimates from the Sleep Review in 2026 that highlight as many as 60% of people in the UK aren’t getting enough sleep. Indeed, less than 7 hours of sleep most nights is considered a lack of sleep. Having persistent short cycles of sleep is linked to a higher body mass index (BMI), weight gain and a higher obesity risk. Indeed, a study from 2020 noted that you are at a 41% higher risk of having a higher BMI if you are regularly sleeping less than 7 hours.

You may have read that when you are trying to lose weight (either by altering diet or with medication), sleep is a crucial part of this process.

But why?

Poor Sleep= Appetite

Sleep directly affects the brain chemicals linked to appetite.

For example, a study published in Appetite in 2026 from Loughborough University looked at 27, 263 adults. This self-report study found that people who had frequent periods of bad sleep had a higher chance of emotional eating. Almost three times higher!

Poor sleep was also noted to be linked to energy-dense food consumption. An earlier study published in Nutrition 2023 found that when young adults were allowed only six hours of sleep each night, compared to the control group, they consumed 34% more calories on average.

Hormone Imbalances

If you are sleep-deprived, what’s happening chemically?

In short, a lot!

Hormones like ghrelin increase with sleep deprivation. This causes you to feel hungry. Then, leptin may also decrease. Leptin is linked to satiety, and with GLP-1s, ones like tirzepatide (Mounjaro) have been found to have a direct impact on both. Indeed, leptin is a hormone that is released from fat cells and suppresses appetite. So, if that drops, hunger spikes.

Cortisol also increases with sleep deprivation. This can then cause a negative feedback loop (pun intended!). Stress reduces sleep and can then cause cortisol to continue to increase. Cortisol has been noted to suppress hormones such as insulin-like growth factor 1 (IGF-1), which is linked to a higher level of fat storage.

Cognitive Impact

Have you ever been tired and made a bad choice? We all have!

Lack of sleep impacts the way the brain works and can impact decision-making. In turn, this can make it harder to make healthy food choices. We have spoken in the past about dopamine. And if you are sleep-deprived, this reward pathway can go into overdrive and create a cyclic effect relating to eating and getting higher dopamine hits, impacting diet. As you are also likely to have lower levels of impulse control when tired, that bowl of ice cream will look more appealing than skinless chicken.

If you are going to start GLP-1medications, the idea of them impacting your beauty sleep can seem counterintuitive. But do these medications impact sleep directly?

Why Do GLP-1’s Impact Sleep?

So, what side effects of Mounjaro vs Wegovy may impact sleep quality?

Acid Reflux

Acid reflux is that horrible burning sensation that happens if you lie down too soon after eating.

However, it can also present as-.

1. Difficulty swallowing.
2. Coughing.
3. Lump in throat sensation.
4. Sour taste.
5. Nausea.
6. Burning in the chest.

Acid reflux has been noted in as many as 1 in 10 people taking Mounjaro or Wegovy. For this, you may need to be prescribed antacids. However, slower gastric emptying (a core part of any GLP-1 treatment) can heighten acid reflux.

Feeling Cold

This is an interesting one.

Feeling cold in bed is nothing new, especially in the cooler months or when you are unwell. However, when you are taking a GLP-1, there may be other reasons why you feel a bit nippy in bed.

Eating less means your body expends less energy. This can make you feel colder due to decreased thermogenesis. GLP-1s also impact brown adipose tissue (BAT). This can also reduce heat generation and has been noted more frequently with tirzepatide (Mounjaro). GLP-1s can also impact vascular responses, which can cause you to have colder hands and feet. If you are diabetic and taking either medication, you run a higher risk of developing hypoglycaemia, which can cause vasoconstriction and prompt cold feet and hands.

As always, if you feel cold excessively at night when taking a GLP-1, be sure to report this. A check of your thyroid and your blood sugar will likely be required to rule out medical causes.

Insomnia

No one likes insomnia.

You are tired, but you cannot go to sleep. You toss and turn, but sleep remains elusive.

Is this directly linked to GLP-1’s? No. However, if you have underlying mental health issues and you are no longer comfort eating to manage those issues, conditions like depression and anxiety can suddenly appear to be more intense. This can lead to sleepless nights or frequent waking.

Let’s break this down.

For Wegovy (2.4 mg) in the STEP trials:

1. STEP 1- 2% noted insomnia (28 people out of 1,306).
2. STEP 2- 2% reported insomnia (seven people out of 404).
3. STEP 3- 5% noted insomnia (19 people out of 407).

For Mounjaro, an analysis of the SURMOUNT 1, SURMOUNT 2 and SURMOUNT 3 trials found:

1. 81 people out of 2,806 reported insomnia (2.89%).
2. This was related to falling asleep and staying asleep rather than prolonged wakefulness.
3. This equates to 3 in every 100 people taking Mounjaro having insomnia, compared to 2 in 100 in the placebo groups.

Data from the trials suggest that insomnia may occur with either Mounjaro or Wegovy treatments. However, these trials cannot say definitively that Wegovy or Mounjaro increase insomnia compared to placebo groups.

Those who took part in these studies were screened prior to participating, and no significant mental health issues were reported. Having mental health conditions such as anxiety or depression is likely to skew these numbers.

However, extreme fatigue has also been noted in those taking Wegovy and Mounjaro. Fatigue linked to Mounjaro was noted in 10.5% of users in the SURPASS CVOT study. In the STEP-1 study, it was noted that 11% of those taking 2.4mg of Wegovy experienced extreme fatigue.

If you are experiencing insomnia or excess fatigue since starting ANY medication, you need to report this to your GP and any specialists who may be prescribing you the medication.

Sleep Apnoea

When you are overweight or obese, you are at a higher risk of developing sleep apnoea.

The NHS notes that this can present as:

1. Loud snoring.
2. Breathing that repeatedly stops and starts during sleep.
3. Gasping, choking or snorting noises while sleeping.
4. Waking up frequently throughout the night.
5. Feeling excessively tired during the day.
6. Difficulty concentrating or remembering things.
7. Waking up with a headache.
8. Mood swings and irritability.
9. Feeling sleepy during everyday activities, including work.
10. Waking up with a dry mouth.

When you start to lose weight, it is safe to assume that sleep apnoea will reduce. Yet, studies into this condition and GLP-1’s have not found this to be the case. Fat around the throat and mouth reduces slowly, prolonging sleep apnoea. So, the condition may reduce, but it may never fully vanish.

Why Choose the Bodyline Clinic for Weight Loss

Insomnia is not something that many people think of as a side effect of weight loss medication.

However, if you have depression or anxiety, you may need more support relating to your mental health and using GLP-1s.

When you come to the Bodyline Clinic, we will assess you in full and look into any medication you may be taking for depression, anxiety or another mental health issue that can impact sleep. We can also discuss your Mounjaro dosage, where relevant, and review any side effects that may be affecting your sleep as part of your ongoing treatment.

What makes us different? We offer help for people who may have:

1. Cardiovascular issues (heart disease)
2. Gastrointestinal diagnoses (Crohn’s disease)
3. Advanced age. We offer GLP-1 treatments to certain people over the age of 75.
4. Mental health issues, such as depression and anxiety.

We don’t provide a quick consultation and sign-off. We create an entire clinical picture of everyone we help.

Do you want something more than a quick meeting and GLP-1s in the post? Contact our team today for a consultation.

Bodyline Works. Bodyline Cares.

FAQ

Does Mounjaro Make You Tired?

Fatigue or feeling tired when taking Mounjaro was noted in 10.5% of users in clinical trials. Real-world users also report fatigue. Possible causes are often linked to a reduction in caloric intake, metabolic changes or dehydration.

Does Wegovy Make You Tired?

When taking injectable semaglutide or the Wegovy pill, the STEP-1 study noted that 11% of those taking 2.4mg noted fatigue. As with Mounjaro, this may be due to caloric intake reduction, as well as changes to metabolism and dehydration.

Can I Take Mounjaro at Night Before Bed?

Yes, Mounjaro can be taken before bed at night, as timing does not impact absorption, efficacy or worsen side effects. If you suffer from minor gastrointestinal side effects when taking Mounjaro, taking this injection before bed may help you sleep through them.