Women have reported terrifying mental health side effects after taking Mounjaro—the popular weight-loss injection used by thousands of people in the UK.

Some describe sudden panic attacks, crippling anxiety and a sensation of ‘tugging in the brain’ after starting the drug.

Mounjaro, along with similar treatments such as Ozempic and Wegovy, can help dieters lose up to 15 per cent of their body weight in a year.

An estimated 1.5million Britons used weight-loss jabs in March 2025 alone—and the new wave of jabs have been hailed as a breakthrough in the fight against obesity.

But growing numbers of patients say they have experienced unexpected mental health symptoms—including insomnia, tremors, shortness of breath and tinnitus.

Although these are not currently listed as official side effects for any of the three major jabs in the UK, an online support group for users suffering such symptoms has attracted more than 2,800 members.

Three members—speaking anonymously to The Times—described the onset of debilitating anxiety, sleeplessness and panic attacks after starting Mounjaro.

One said the anxiety felt like a kind of ‘terror’ she had never experienced before.

The cases have prompted fresh questions over the safety profile of the medications as their use becomes more widespread.

The ingredient tirzepatide, available as Mounjaro, has been hailed the 'King Kong' of slimming jabs and a breakthrough in the war on obesity

The ingredient tirzepatide, available as Mounjaro, has been hailed the ‘King Kong’ of slimming jabs and a breakthrough in the war on obesity

Charlotte Lloyd, 37, a social media manager from London and member of the online group, had anxiety symptoms so bad she found herself in A&E, The Times reported.

Last autumn she gained weight during her fertility treatment, so she had a BMI high enough to qualify for the prescription weight-loss jab Mounjaro.

While NHS access to the weight loss jab remain limited, the Mounjaro jab is widely available through online doctors and private clinics.

To be eligible you must have a BMI of 30 or more, or a BMI between 27 and 30 (overweight) and a weight-related health condition such as prediabetes.

Ms Lloyd said it was a simple process to access the jab privately through Asda Online Doctor by Zava—requiring her medical history, weight, height and some photographs.

But her nightmare began within days of taking her first weekly 2.5mg dose, when she ‘almost immediately’ lost her appetite and started having difficulty sleeping.

The next week after her second dose, she said ‘the wheels fell completely off’ when she ‘stopped sleeping all together’.

‘I tried sleeping pills, antihistamines—nothing worked. I may as well have been eating sweets. After two nights awake I started to feel like I was losing my mind,’ she said.

It is estimated a 1.5 million people in the UK used weight-loss jabs, which have been hailed the solution to the obesity epidemic, in March 2025

It is estimated a 1.5 million people in the UK used weight-loss jabs, which have been hailed the solution to the obesity epidemic, in March 2025 

It wasn’t just difficulty sleeping, three days after she started experiencing symptoms, she went to A&E when her ‘heart was pounding nonstop’.

In the hospital an ECG revealed her heart was above the normal resting heart rate for adults, which is between 60 and 100 beats per minute.

But while it was 105bpm compared to her normal resting heart rate of 70bpm, the rhythm wasn’t irregular, so she was discharged.

‘I explained I hadn’t slept in days and they basically told me to go home and have a bath,’ she said.  

Despite still struggling to sleep, her GP was unable to help, as she had ‘reached the limit of what she could prescribe’.

Things got worse when she was hit by a series of panic attacks and tremors for five weeks—which she likened to ‘swallowing an earthquake’.

Although she had noted in her application for the medication she had experienced some anxiety and insomnia in the past, it was still approved.

But the anxiety she now experienced she described as ‘a physical terror I’ve never known. Like a switch had been flipped in my brain.

Things got worse when she was hit by a series of panic attacks and tremors for five weeks—which she likened to 'swallowing an earthquake'

Things got worse when she was hit by a series of panic attacks and tremors for five weeks—which she likened to ‘swallowing an earthquake’

‘I went into a constant state of fight-or-flight—like a bad drug trip that wouldn’t end. I couldn’t see how I was going to be able to survive it.’

Initially signed off work unable to ‘do anything’ or even ‘follow a conversation’, she later resigned with her relationship ending that same week.

The woman who said her life ‘just fell apart’, said: ‘The way I see it, it’s a roll of the dice as to how you’re going to react to these drugs.

‘If people knew that they could have potentially catastrophic mental and physical side-effects, they could make a more informed decision about taking them.’

Ms Lloyd isn’t the only one experiencing psychological side effects—another woman also found herself in A&E after taking the jab.

Maria Edwards, ended up in hospital last year only 48 hours after taking her first dose of the Mounjaro jab.

When her BMI was over 30, so she too qualified for the weight loss jab which got from the online doctor, MedExpress. 

‘I thought I was having a heart attack,’ she said, but her scans, x-trays and bloods taken, all came back clear.

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She said: ‘I’ve never had any mental health problems. I’ve never had a panic attack or anxiety. I’ve always been a laid-back person and now it’s like everything is stressful. 

‘I get this thing that we’ve termed ‘air hunger’ where it’s like I can’t take a deep breath. If I’d have known Mounjaro could have mental health side-effects I never would have taken it.’

The third woman, Julie Peters, a 31 year-old mother from Birmingham had a similar experience after getting the jab.

She had a panic attack that lasted two hours on January 11, after taking the lowest dose, 2.5mg, of Mounjaro, once a week for two months.

The mother went to A&E also thinking she was having a heart attack, but similarly she said: ‘tests on my heart, kidneys, and for pancreatitis all came back clear.

Ms Peters also described experiencing tremors, a ‘tugging’ sensation in her brain’ and tinnitus—’The ringing in my ears has been constant, sometimes with multiple ringing sounds. 

‘The pressure and heaviness in my brain make me feel dull, disconnected and nauseous, and I also have a sensitivity to motion.

‘I recently requested a brain MRI, and while the results came back normal, I am relieved yet uncertain about what to do next. It’s incredibly suffocating,’ she said.

It follows a study published in January last year in the International Journal of Clinical Pharmacy which found 481 psychiatric events were linked to weight loss jabs.

The ‘seriousness of the adverse events warrants additional research’ to explore the causual relationship,’ said lead authors, Hajer Elkout and Mansour Tobaiqy.

This was despite psychiatric events only accounting for 1.2 per cent of total reports associated with the active ingredients in weight loss medications.

Anxiety, depression nor insomnia were listed as potential side effects by Asda Online Doctor by Zava or in the patient leaflet they refer patients to. 

The clinical governance team at the private pharmacist who stressed patient safety told The Times all applicants are required to give their medical history. 

This includes their GP details which they said enables the GP to inform them ‘of any discrepancies or concerns they have with the prescription’. 

They added there are studies evidencing mental health can be improved with treatment, and no clinical-based-evidence of a negative impact ‘they are aware of’.

Last year a study published in the journal of Natural Medicine found taking semaglutide for weight loss or diabetes reduced the incidence of suicidal ideation.

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However, a more recent study found Ozempic and Mounjaro can raise the risk of depression and suicidal thoughts.

However, Asda Online Doctor by Zava added: ‘Our doctors, of course, will provide suitable advice to any particular patients of concern or who are managing complex mental health issues and may not be able to use the treatment appropriately alone. 

‘These patients, where necessary, will be signposted to their GPs for further support to manage their weight.’

The manufacturers of Mounjaro, Eli Lilly, and of both Ozempic and Wegovy, Novo Nordisk told The Times patient safety was their top priority.

‘We take any reports about patient safety seriously and actively monitor, evaluate and report safety information for all our medicines,’ said Eli Lilly.

With Novo Nordisk adding it welcomes: ‘Independent research investigating the safety, efficacy and clinical utility of our products.’

The two drug companies both highlighted that the UK regulatory agency had assessed the risk and benefits approving their respective drugs.

Novo Nordisk added that independent analysis ‘did not find an association between use of GLP-1RA medicines and the occurrence of increased risk of suicidal thoughts or actions.’

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