To many, the new wave of weight-loss jabs are a wonder of modern medicine – an almost instant way to curb appetite and banish ‘food noise’, while the pounds fall away.
But increasing numbers of users are reporting alarming side effects.
Among them is Daily Mail columnist Nadine Dorries, who recently revealed that one such drug, Mounjaro, left her with agonising heartburn.
She fears this has damaged her throat so severely that she is now at risk of developing oesophageal cancer. And Ms Dorries is far from the only one.
As a pharmacist with more than 30 years’ experience, I’m becoming increasingly concerned by the rise in patients suffering serious, long-lasting gut issues caused by the very injections that are supposed to help them.
These conditions are life-changing – and it’s why I feel compelled to speak out.
Part of the way these drugs work is by slowing the stomach, so people feel full faster. That’s why they’re so effective for weight loss – but for some, this same effect can become a curse.
The condition I’m seeing alarmingly more of is gastroparesis, where the stomach can no longer move food along at a normal rate.
Pharmacist Deborah Grayson has heard of life–changing complications caused by weight loss jabs, including permanent gastroparesis
Symptoms are relentless: people feel full after tiny amounts of food, suffer nausea or vomiting, bloating, stomach pain and heartburn.
Yet this side effect is not listed anywhere on the Mounjaro patient information leaflets.
What’s even more concerning is that, although we once believed these problems would resolve when the injections were stopped, we are now discovering this isn’t always the case – leaving some patients with permanent symptoms.
This is not just uncomfortable; it’s debilitating. Eating becomes stressful, nutritional intake drops, and in severe cases malnutrition can occur.
Something as simple as enjoying a family meal can turn into an ordeal – and many sufferers begin to waste away.
Gastroparesis is a rare, chronic condition. Only around 14 in every 100,000 people are diagnosed with it in the UK.
While it affects people of all ages, women are twice as likely to suffer, and according to the charity Guts UK it is most often diagnosed in those aged 18 to 39.
In the US, hundreds of patients have joined a a multi-state US lawsuit against the drugmakers of Mounjaro—Eli Lilly—and another jab, Ozempic, prescribed for diabetes but also used for weight loss.
There is a class action law suit against Mounjaro manufacturer Eli Lilly in the US
Thousands more patients who also suffered extreme side-effects—including gastroparesis—are expected to join the legal action as it progresses, lawyers say.
Pharmaceutical firms Eli Lilly and Novo Nordisk are accused of failing to warn patients or physicians about certain side-effects caused by the drugs.
Both companies have said they will ‘vigorously defend against these claims’ and deny the allegations in the lawsuits.
One 56-year-old woman diagnosed with gastroparesis, who is part of the class action, told the Daily Mail that she now faces being fed with a tube for the rest of her life.
But I fear, as weight loss jabs are ever more widely prescribed, we will begin to see more and more fall victim to this devastating condition.
What concerns me further is that these gut symptoms often lead to more prescriptions of stomach acid-reducing medications, such as proton pump inhibitors (PPIs).
These are among the most widely prescribed drugs in the UK, yet long-term use has been linked to a range of conditions, including dementia.
Nadine Dorries experienced these disturbing side effects herself.
Within days of her first Mounjaro injection last June – prescribed after she was found to be pre-diabetic, with fatty liver disease and high cholesterol – she developed severe heartburn.
Delayed gastric emptying is a painful and debilitating condition (file photo)
At first she relied on over-the-counter Gaviscon to control the pain – but when she stopped the jabs in January, her acid reflux only worsened.
By the summer she was being treated with ‘two double doses’ of PPIs, which block acid production. Weeks later, another attack left her needing an endoscopy.
She recalled: ‘I received a diagnosis of Barrett’s Oesophagus, and the distressing news that it increases the chances of oesophageal adenocarcinoma, a form of cancer.
‘Barrett’s is, in short, a protective but abnormal change in the lining of the oesophagus caused by acid reflux. Four inches of my oesophagus had been damaged by excess acid.
‘The risk of disease is small but oesophageal cancer has one of the worst of all five-year cancer survival rates — just 20 per cent.’
Nadine is one of a growing number of patients on GLP-1s who present to their GPs with heartburn or reflux-like discomfort. The obvious response is to treat it with a PPI.
While this can relieve acid-related pain, it does nothing to address the real problem: delayed gastric emptying.
In fact, in patients with gastroparesis, PPIs can sometimes worsen symptoms, compounding digestive difficulties rather than resolving them.
And with GLP-1 medications now being prescribed at higher doses to maximise weight loss, I fear we will see more people facing not only persistent gastroparesis but also a lifelong reliance on PPIs.
The irony is stark: a treatment intended to improve health – by reversing type-2 diabetes, improving cardiovascular outcomes and even cutting the risk of substance abuse – can at the same time leave patients with devastating gastrointestinal complications and locked into additional medication use.
That is why I would urge both patients and healthcare professionals to take this seriously.
Anyone starting these injections should be fully informed about the potential for severe and, in some cases, permanent digestive problems.
Doctors need to monitor symptoms closely and consider alternatives for people with a history of gastrointestinal issues.
And patients who experience persistent nausea, vomiting, bloating or early satiety should speak to their GP without delay. Early recognition may help manage symptoms before they become chronic.
GLP-1 medications have a place in treating obesity and diabetes. But the risks are real, and awareness is crucial. Permanent gastroparesis destroys quality of life. We cannot afford to ignore this silent, debilitating side effect.
Deborah Grayson is a Pharmacist and nutritional therapist who runs Digestion With Confidence a specialist nutritional service helping people suffering from acid reflux.
