Weight-loss wonder jabs such as Mounjaro and Wegovy are helping to transform the lives and health of millions.

But one in five users stops taking these drugs within a year, due to intolerable side-effects ranging from nausea and vomiting to gallstones and pancreatitis – a serious infection of the pancreas.

The majority then pile weight back on, as studies show at least 90 per cent of those who quit the jabs regain what they lost.

But could a stick-on pad, that looks like a giant Band-Aid and is placed on the stomach for just a few hours, reduce the drop-out rate – by enabling people on the drugs to ensure they’re taking the correct dose?

The Gastric Alimetry pad is stuck on to a patient’s stomach to determine the precise rate at which it empties when they’re taking the drugs.

Fat-busting jabs work in two ways – they mimic the effects of a hormone called GLP-1, which tells the brain that the stomach is full. And they also slow down the rate at which the stomach empties, making us feel fuller for longer.

Too high a dose of the drugs can slow the emptying process too far, leading to nausea, vomiting and constipation.

One in five users of weight-loss wonder jabs such as Mounjaro and Wegovy stop taking them within a year, due to intolerable side-effects ranging from nausea and vomiting to gallstones and pancreatitis – a serious infection of the pancreas

In more severe cases, it can cause gastroparesis – or stomach paralysis – where the stomach muscles are weakened and food is not digested properly. The worst-case scenario here is that surgery is needed to insert a feeding tube to temporarily bypass the stomach, or to remove a mass of undigested food.

However, too low a dose can mean the stomach empties too quickly for the drug to be effective.

Weight-loss jabs are usually started at a dose of 0.25mg once a week, rising gradually to 2.4mg after around four months. But effects vary – and working out the correct dose can be informed guesswork.

In addition, there have been reports of websites selling pens (for self-injecting) containing either the wrong dose or no active ingredient at all.

And it’s hoped the device, developed in New Zealand, could help doctors work out precisely what dose each patient needs.

Packed with dozens of tiny electrodes, the high-tech pad carries out something called an electrogastrogram – which measures the stomach’s electrical activity (from stomach contractions) – in much the same way as an electrocardiogram (ECG) tracks the heart’s electrical signals.

This enables medics to map a clearer picture of how the stomach is functioning.

The normal rate for a healthy stomach to empty is two to four hours – but studies suggest that this can be much slower in patients taking semaglutide, the active ingredient in Ozempic and Wegovy.

Could a stick-on pad, that looks like a giant Band-Aid and is placed on the stomach for just a few hours, reduce the weight-loss jab drop-out rate – by enabling people on the drugs to ensure they’re taking the correct dose?

After four hours, most patients’ stomachs are still 30 per cent full.

The Gastric Alimetry pad is connected to a small electronic box or reader, which is paired with an app on an iPad.

Patients fast for at least six hours beforehand to ensure an empty stomach, then consume a cereal bar. The device monitors electrical activity over four hours as the food passes through the stomach.

The device, designed as a non-invasive alternative to endoscopes (where a camera is passed down the throat attached to a tiny tube), is already being used in some private clinics to assess patients with conditions such as acid reflux.

A trial is also under way at University College London involving NHS patients with chronic stomach symptoms who have not been helped by previous treatments.

Meanwhile, a study by scientists from the University of Auckland in New Zealand backs the idea it could be used to help people on GLP-1s.

The researchers, whose work was published in the journal Gastroenterology in May, used the pad to measure stomach function in 20 healthy volunteers who’d been given different doses of the drugs.

In 15 per cent of cases it detected that the drugs had trigged gastric dysrhythmia, when the stomach’s pulses become chaotic, causing a range of symptoms including nausea, early fullness and sometimes vomiting.

Dr Rehan Haidry, a gastroenterologist at the Cleveland Clinic in London, says that the Gastric Alimetry pad gives doctors the ability to measure actual stomach function reliably – something an endoscopy, which offers a visual examination of the food pipe for instance, cannot.

He told Good Health: ‘This device will find the ideal point at which the stomach is slowly emptying but not so slow that it causes the side-effects.’

Professor Anthony Hobson, a gastrointestinal clinical scientist at the private Functional Gut Clinic in London, agrees: ‘Rather than people giving up on these jabs, this technology could find the “sweet spot” so they would still have the weight loss but not endure some unpleasant side-effects.’

It is, however, not cheap.

For patients who want to undergo the test privately, it costs £1,875 and Professor Hobson admits that ‘only the patients with the highest medical needs and worst side-effects might choose this approach’.

And new ways to avoid side-effects when taking weight-loss jabs are being investigated.

A study in the Journal of Clinical Medicine in 2022 found eating foods such as crackers, apples or mint might help those suffering with nausea.

Meanwhile, research published in the journal Obesity Pillars in May this year also found that acupressure wristbands, normally worn to ease travel and morning sickness, could alleviate nausea symptoms in people taking GLP-1s.

In a group of 31 people who were taking the weight-loss jabs and suffering from nausea, it led to an 80 per cent reduction in the severity of their nausea.

It’s thought pressure on certain nerve pathways in the wrist calms the nervous system and regulates stomach muscle function.