Mounjaro and depression: side effects, low mood, and what to do

Studies of Mounjaro show that there is no significant evidence that Mounjaro causes depression. The evidence that shows Mounjaro does not cause depression comes from the SURMOUNT trials, which were used to show that Mounjaro is a safe and effective medication. There were 4 different studies done that included results from 1,000’s of patients, and no mental health or mood changes were reported as side effects while taking tirzepatide for up to 72 weeks.

However, this does not mean depression cannot affect people taking Mounjaro. It just means that it’s not proven that Mounjaro is definitely the cause of depression in people who experience it while on treatment.

It is possible that someone could experience depression as a result of taking Mounjaro. It may also be that the evidence linking Mounjaro and depression becomes clearer over time as more people use the medication and more studies are done on Mounjaro side effects.

Depression is not listed as a known side effect of Mounjaro in the patient information leaflet that comes with the medication or in the clinical studies carried out on the medication for regulatory approval. That means there is not enough clinical evidence to say for sure that Mounjaro can cause depression as a side effect. It does not mean that it’s impossible for someone to experience depression when taking Mounjaro.

One study showed that just over 1 in 100 people report some kind of mental health side effect while using weight loss injections. Of these people, over half will experience depression as a mental health side effect. However, it’s also important to be aware that mental health can change at any time, so it’s difficult to know for sure if this is linked to Mounjaro use or something else.

Studies also show that Mounjaro can cause a related side effect – fatigue. Fatigue is not exactly the same as depression, since it causes tiredness but does not necessarily cause low mood. Still, fatigue and depression are closely linked, and it’s not always easy to tell them apart if you’re experiencing them. Fatigue affects up to 1 in 10 people who use Mounjaro.

Although mood changes are not listed as a known side effect of Mounjaro, there are a few other ways that Mounjaro might indirectly affect your mood, including:

• low blood sugar or energy from eating less
• hormone level changes
• effect on reward pathways in the brain
• changes to the digestive system
• rapid weight loss and changes to body shape

Low blood sugar or energy from eating less

Not only can Mounjaro cause low blood sugar as a side effect (usually if taken with other diabetes medications), but it also reduces appetite. This means you might find it harder to eat enough to keep your energy and blood sugar levels up, which can lower your mood. Dieting is an important part of weight loss treatment, but it can be hard to get the balance right, and it’s important to still eat enough even when you’re looking to lose weight.

Hormone level changes

Mounjaro can cause significant changes to the level of hormones in your body. Hormonal changes can be closely linked to your mood, and it’s possible these changes affect the way you feel. As the levels of these hormones go up and down, it’s possible to experience mood swings as a result.

Effect on reward pathways in the brain

Part of how Mounjaro reduces appetite is by making it less satisfying to eat food. This can help people avoid overeating, but it also means people can find food less comforting and rewarding. If enjoying food is a way of coping emotionally, then losing that may have a negative effect on your mental health.

Changes to the digestive system

Digestive health and mental health are closely linked. Weight loss injections like Mounjaro can cause a number of digestion-related side effects and might disrupt the bacteria that already live in your gut. As a result, this can have an impact on your mood.

Rapid weight loss and changes to body shape

Losing weight fast can put a lot of strain on your body. Some people may also notice their appearance changing drastically, which can be distressing. The so-called ‘Mounjaro face’ or Mounjaro hair loss are examples of how GPL-1 medications can have a noticeable impact on the way you look, which can impact your mood.

It is possible for Mounjaro to have a negative impact on people who already have depression. While there has not been extensive research done on the effects of Mounjaro on people who already have depression, the evidence shows at least 1% of people who take GLP-1 medications like Mounjaro do experience depressive symptoms. It is not clear exactly how many people who have depression might get worse symptoms from taking Mounjaro, though.

Since a number of possible side effects of Mounjaro can affect mood or be difficult to manage, these can then make existing depression worse. Also, because Mounjaro affects reward pathways, it can reduce the amount of pleasure you feel, especially when eating. Anhedonia (reduced feelings of pleasure) is a common factor in depression for many people who experience it.

It is also possible that Mounjaro could improve symptoms of depression. One study looking at the SURMOUNT trials focused on the impact on depression. This research actually shows a slight improvement in depression scores following Mounjaro treatment. There are a number of reasons why this could be the case, including:

• more stable levels of dopamine and serotonin – research shows GLP-1 medications can have several benefits for brain function, like reduced inflammation, better neuron activity, and increased levels of neurotransmitters related to pleasure and happiness
• the physical health benefits of weight loss – GLP-1 injections are known to improve insulin resistance, metabolism, gut health, and increase mobility through weight loss, which can all link to improved mental health and mood
• the positive mental health impact of weight loss – losing weight itself can lead to more motivation, better mood, lower fatigue, improved self-image, less food noise, and less anxiety about food and weight

It is possible that any mood-related side effects do improve over time. Most side effects of Mounjaro appear when you first start treatment or when you increase your dose. Within a few weeks, many common side effects improve or go away entirely.

It could be that any low mood or depressive symptoms you might get when starting Mounjaro also go away. It is also possible that these symptoms do not improve and you have to consider how to manage them long term.

If you’re taking Mounjaro and you experience low mood or symptoms of depression, it can understandably be worrying. But there are steps you can take to improve things for yourself, and you may not need to stop your treatment.

If you are experiencing low mood while taking Mounjaro:

• consider other factors that might be causing your low mood – remember Mounjaro is not known to cause depression or low mood, so there may be other more likely causes
• remember that side effects usually improve over time – if you have just started treatment or increased your dose, things may improve in a few weeks
• think about reducing your dose – dropping to a lower dose of Mounjaro can improve side effects, and it’s still possible to lose weight taking a lower dose long term
• make sure you’re eating properly – if you do not eat enough or get enough nutrients in your food, it can impact your mood, so make sure to follow a good Mounjaro diet plan

The NHS provides advice on how to manage low mood, including:

• contacting Samaritans
• getting peer support through Mind
• practicing mindfulness

You should consider talking to a doctor if you have any concerns about your medication or your mood. They can help you manage your medication, diet and exercise plan, so you can get the most out of your treatment. In particular, it’s important to contact your GP if you:

• have had low mood for 2 weeks or more
• feel like you’re struggling to cope with your low mood
• have tried to improve your mood on your own and it is not working
• would like to get a referral from a GP to specialist mental health services

What is ‘Mounjaro anhedonia’?

Anhedonia means losing the ability to feel pleasure. The phrase ‘Mounjaro anhedonia’ could refer to the reduced pleasure you experience from eating, which is part of the effect Mounjaro has on the reward pathways in your brain to reduce appetite.

It could also refer to a more general feeling of reduced pleasure, which is not specific to eating. While anhedonia is not a known side effect of Mounjaro, it may be possible that you can experience it during treatment.

Does Mounjaro lower dopamine production?

Mounjaro does not lower overall dopamine production. In fact, it’s possible that Mounjaro can actually improve dopamine levels. However, Mounjaro does reduce the reward pathway around eating. This means your body may release less dopamine in response to food, making it feel less pleasurable to eat.

Will my antidepressant still work on Mounjaro?

Mounjaro has not been shown to interact directly with any antidepressants. However, it is possible that the effect Mounjaro has on your digestive system affects how well your antidepressants are absorbed. Slower digestion may cause them to be absorbed more slowly, while any side effects like diarrhoea or vomiting may stop them being absorbed properly.

Can a higher dose of Mounjaro cause more depression?

There is no evidence that Mounjaro causes depression, even at higher doses. However, other side effects that may affect mood can become more intense at higher doses. This is most likely to happen when you first increase your dose, and the effects may go away. However, it is possible that your mood is affected long-term on a higher dose of Mounjaro.

Is there a link between Mounjaro usage and suicide?

There is no evidence to show a link between Mounjaro and suicidal thoughts or behaviour. One study found that Mounjaro has a lower rate of suicidal thoughts and behaviours compared to other weight loss medications. Still, suicide does happen even for people using medications, although that does not mean the medication is the cause.

You may encounter news stories or articles online that emphasise a link between Mounjaro and other weight loss medications and suicide. Often, when a person commits suicide while taking medication, or if there are any other factors that people might believe are related, this gets focused on in media coverage.