The ultimate guide to Mounjaro hacks that promise to supercharge your weight loss - experts' verdict on which work... and the ones to avoid at all costs

Doctors are warning against dangerous weight-loss jab 'hacks' spreading online, as patients chase ways to supercharge results.

More than a million Britons are now injecting themselves weekly with drugs such as Mounjaro and Wegovy – bought online or through private clinics – lured by promises of rapid results.

Known collectively as GLP–1s, they can help users lose up to a fifth of their body weight in a year and have upended the obesity treatment playbook.

But as demand surges, so too does the spread of unverified tips and tricks – ranging from combining the jabs with other medications to extreme diets and punishing workout regimes.

Some methods are backed by science – and promise a way to assure the greatest weight loss while minimising side effects.

Others are not just ineffective, but could pose a serious risk to health.

With the help of top doctors and obesity experts, we separate the facts from the fads...

Less is more when it comes to Mounjaro

Most people on weight–loss jabs don't need the highest doses to see dramatic results, new research suggests.

A study published last week, involving more than 100 patients on GLP–1 drugs such as Mounjaro and Wegovy, found that the vast majority – 86 per cent – lost a significant amount of weight while taking relatively small amounts of the medication.

In fact, some of the best results were seen at just half the maximum dose. Every patient who lost more than a third of their body weight was on the 7.5mg dose – only a few steps above the starter amount of 2.5mg.

Kiran Jones, clinical pharmacist at Oxford Online Pharmacy, which carried out the research, said: 'This shows that healthy, sustainable weight loss is possible without ramping up to the highest dose.

It's not just about how much you take – lifestyle, general health and sticking to the plan all play a big part.'

Professor Carel Le Roux, an expert in metabolic medicine at Ulster University, agreed: 'The aim is to stay on a dose that doesn't cause side effects, so the medication can be used long term and deliver full health benefits.'

Previous studies have also shown that those on the strongest doses are more likely to pile the weight back on once they stop.

Tam Fry, chair of the National Obesity Forum, said: 'It shouldn't surprise anyone if people regain weight after using these drugs without making serious changes to their lifestyle. They are not a quick fix.'

Prunes could ease painful side effects

Constipation affects up to one in ten users of slimming jabs like Mounjaro – and in rare cases can lead to painful complications such as piles and tears.

But experts say a handful of prunes a day could offer a simple fix.

The dried fruit, which costs as little as £1.20 a pack, is rich in fibre and sorbitol – a natural sugar that draws water into the bowel, helping to soften stools and make them easier to pass.

Dr Simon Steenson, a nutritional sciences expert at King's College London, told MailOnline: 'Getting more fibre in your diet can help bulk up stools. Prunes specifically contain sorbitol, which softens them by increasing their water content.'

One study involving 120 people found prunes significantly boosted stool weight and frequency, and were well tolerated, according to researchers writing in the journal Clinical Nutrition.

Another trial, presented at the European Congress on Obesity, tracked 100 overweight adults and found that eating a handful of prunes twice daily helped curb appetite and speed up weight loss.

By the end of the three–month study, participants had shed 4lb and trimmed an inch from their waistlines – with weight loss accelerating in the later stages.

Limit sugar intake to ease nausea

There are no banned foods for users of weight–loss jabs like Mounjaro – but experts warn that certain items could make side effects worse or reduce the drug's effectiveness.

Greasy, fried or high–fat foods can trigger or worsen nausea, vomiting and diarrhoea – common side effects of GLP–1 drugs, according to research.

Meanwhile, sugary treats such as sweets, fizzy drinks and desserts may spike blood sugar levels, increase insulin resistance and ultimately blunt the impact of the medication.

Dr Simon Steenson, a nutrition scientist at King's College London, said: 'You can cut down on sugar by swapping sweet treats for fruit and yogurt, choosing lower–sugar versions of foods and watching your portion sizes.'

Stable blood sugar levels help regulate hunger and keep energy consistent – meaning the urge to snack often fades.

Stuart Gale, chief pharmacist at Oxford Online Pharmacy, added: 'Fruit is great for fibre and vitamins, but don't overdo it – as it still contains natural sugars and calories.

'Try to get at least half your fruit intake from whole fruits like apples, bananas and berries. You can also include 100 per cent fruit juice, or tinned or dried fruit – just in moderation.'

Don't fall for the microdose fad

A growing number of weight–loss jab users are turning to so–called 'microdosing' in a bid to minimise side effects – but experts say the trend is unsafe, unregulated and potentially life–threatening.

The term, originally coined for using tiny amounts of psychedelics to treat mental health conditions, now refers to counting clicks on pre–filled GLP–1 injection pens to deliver less than the prescribed dose – or even breaking them open.

Some users claim this allows them to keep shedding weight while avoiding nausea or vomiting. Others, particularly in the biohacking community, reportedly use the jabs as part of a broader 'anti–ageing' regime.

But leading doctors have issued urgent warnings.

'People are risking serious side effects from overdosing, as well as the potential for life–threatening infection,' said Professor Alex Miras, an endocrinologist at Ulster University. 'We cannot endorse it.'

He added: 'Not only is contamination a risk, but it also reduces the effectiveness of the medication.

The pens can malfunction when people count clicks instead of using them properly – and they expire after six weeks. Once opened, they're no longer sterile, which can introduce bacteria.

Earlier this year, a Lancet editorial warned: 'The practice of microdosing drugs is not new – but there is no evidence that it works for obesity.'

'Golden dose' that spells danger

Each Mounjaro pen contains 3ml of liquid, and each dose uses 0.6ml – just enough for four, accurate, pre–measured doses of Mounjaro.

But this leaves a small amount of liquid behind that a growing number of Mounjaro users are attempting to squeeze out, dubbed the 'golden dose'.

The cost–saving appeal is clear. By getting five doses out of each pen, regular users could save around £615 a year.

The leftover liquid, however, is not a bonus dose – it's a deliberate overfill built into the pen to ensure complete delivery of each injection.

The overfill ensures there's enough liquid for a flow check before each dose and accounts for any small variances in delivery.

Similar to microdosing, health chiefs have also repeatedly urged patients against trying the hack, warning they could both physically injure themselves when trying to remove the fifth dose from the pen and risk infection.

Dr Alison Cave, chief safety officer of the MHRA, said: 'People should follow the dosing directions provided by their healthcare provider when prescribed weight–loss medicines and use as directed in the patient information leaflet.

'Medicines are approved according to strict dosage guidelines.

'Failure to adhere with these guidelines, such as tampering with pre–dosed injection pens, could harm your health or cause personal injury.'

Under–eat... and you could regret it

Hundreds of jab users have flocked to social media forums urging other slimmers to take up the OMAD diet while on the injections.

An abbreviation for 'one meal a day', the diet does exactly what it says on the tin –consuming all daily calories in a single, one–hour eating window.

Coldplay frontman Chris Martin reportedly swears by it. Proponents say it cuts cravings, boosts energy and even turbo–charges sex lives.

But combining these approaches to achieve rapid weight loss could trigger chronic health issues like digestive conditions or cause widespread loss of muscle mass, experts have warned.

Dr Sherry Ross, an associate professor of urology at the University of North Carolina and author of She-ology: The Definitive Guide To Women's Intimate Health. Period said such rapid weight loss may also impact muscles including the pelvic floor.

'This raises the risk of a prolapse, urinary incontinence, and faecal and gas incontinence,' she added.

Other forum users also warned of such side effects.

In one Reddit forum with over 36,000 members, one said: 'From personal experience and having a GP nearly pull me off the medication, not eating enough calories and losing weight quickly will lead to muscle loss and potentially liver damage.'

Professor Naveed Sattar, a professor of metabolic medicine at the University of Glasgow, added: 'Any mechanism that helps people control their calorie intake will help them lose weight – the key issue is whether one meal per day is sustainable in long term.