Mounjaro makes you feel full by acting like two of the body’s natural hunger hormones, GLP-1 and GIP. Because one way it does this is by slowing your digestion, its side effects are mostly to do with the gut.
Yet some people using it report having insomnia, where they regularly have trouble sleeping.
Does Mounjaro affect sleep?
Mounjaro weight loss injections aren’t known to directly disturb sleep; there’s no official Mounjaro sleep side effects.
However, some people taking it do report having issues getting to sleep. Though this doesn’t appear to be common: in a scientific review of social media posts, around 1% described experiencing insomnia while on weight loss medicines such as Mounjaro. Here, sleep troubles might be a knock-on effect from other symptoms, like constipation or mental health side effects.
On the other hand, tiredness is a Mounjaro side effect. That means that Mounjaro might actually make you feel sleepy! There’s also research suggesting that it could help with sleep apnoea (more on this later).
Is insomnia a side effect of Mounjaro?
Not officially. Insomnia has not been reported in clinical studies. But as we mentioned earlier, it might be brought on by other Mounjaro side effects.
For instance, Mounjaro can cause vomiting, indigestion, constipation, and diarrhoea, which could all keep you from a quality night of shut-eye. There are also reports that it can affect your mental health—and this can mess with your sleep, too.
Side effects support at Voy
"If you're using Voy and you experience any side effects, rest assured that our expert clinicians are just a message or phone call away. They can adjust your dose, prescribe medication to ease your symptoms, or simply offer reassurance.
Everyone responds differently to weight loss treatment and we'll help you find what feels right for you."

Mounjaro and mental health side effects
A small number of people on Mounjaro have reported mental health side effects. And this may in turn affect their night’s rest. Both depression and anxiety are potential causes of insomnia.
However, experiencing depression and anxiety on Mounjaro is rare. The Medicines and Healthcare products Regulatory Agency (MHRA) has found no evidence of a link between GLP-1 agonists and the risk of depression, suicidal thoughts and self-harm.
However, data is limited and we need more research to fully understand the link between Mounjaro and mental health.
Anecdotally, some people say they’ve experienced brain fog on Mounjaro. Again, this isn’t an official side effect, but it can happen when you’re tired or sleep-deprived.
How long does Mounjaro insomnia last?
But does Mounjaro insomnia go away? Mounjaro side effects tend to come on when you start the medicine or increase your dose. They’re usually mild and tend to resolve on their own.
So, if your insomnia is being brought on by symptoms like nausea or vomiting, it should clear within a few days or weeks. Check in with your provider if your symptoms don’t go away or are getting worse.
Tips to manage Mounjaro sleep issues
Still can’t sleep on Mounjaro? These tips might help.
Healthy sleep habits
Building a good sleep routine is the best way to get a solid night’s rest. That includes putting aside at least an hour to wind down before bed and turning in at the same time every night.
Eat a balanced diet
Eating a nutritionally rich, balanced diet may reduce your risk of insomnia. Not getting enough fruit and veg, and having too many foods that are high in fat and sugar have all been associated with worse sleep.
Move your body
Regular exercise can help relieve insomnia and improve the quality of your sleep. Aim to do at least 150 minutes of moderate-intensive movement and two strength sessions per week.
Can Mounjaro help with sleep apnoea?
It might. Sleep apnoea is when your breathing stops and starts while you’re asleep. Being overweight increases your risk of developing it—and losing weight can help to treat it.
So, by supporting weight loss, Mounjaro may be able to help. Clinical trials show that Mounjaro improves sleep apnoea scores in some people.
However, research on medicines like Mounjaro (such as Wegovy weight loss injections, that work by acting like GLP-1) has sometimes been conflicting, so we need more evidence to understand how weight loss medication could be used for sleep apnoea.
When to talk to your doctor
If you’ve tried to change your sleeping habits but it hasn’t helped, or if your symptoms have hung around for months and are affecting your day-to-day life, it’s time to check in with your doctor.
They will try to find the root cause of your insomnia and help you get the right treatment.
Your weight loss journey
Mounjaro side effects are usually nothing to worry about—and your provider will only prescribe it if it’s safe for you to take. So please don’t let the above put you off exploring your options.
As part of our weight loss programme, we’ve got a dedicated side effect support line that you can ring with any questions. You’ll also get monthly weight loss medication, like Mounjaro, Wegovy, or Saxenda weight loss injections, or orlistat weight loss pills—plus one-to-one support from our coaches and clinicians.
Take our quiz to find out if you’re eligible. It won’t take more than a few minutes.