How to tell if Ozempic is right for you: How likely you are to suffer side-effects, the risks - and whether it will really work. Read our special report

From the breathless coverage 'miracle' weight-loss jabs Wegovy and Ozempic have had so far, you'd be forgiven for thinking they were the cure for every ill.

Designed originally to treat type 2 diabetes – and transforming the lives of those living with the condition – they have also become a global panacea for people with obesity.

A-list celebrities allegedly swear by them to keep them thin and glossy. Headlines suggest they can improve your heart health. And if the anecdotes are true, they might even curb addictive behaviour such as gambling, smoking and drinking too much alcohol.

But, as with any drug, there is a flip-side.

A study earlier this month linked the active ingredient in both drugs, semaglutide, to an increased risk of a condition that causes blindness.

Experts from the Society for Acute ­Medicine have also warned of a 'real increase' in the number of people coming to hospital with complications such as nausea and ­vomiting linked to the medication.

But how significant are these risks, really? And, if you're curious about taking it yourself, how can you work out whether you really will benefit? Here, the experts tell you everything you need to know so you can make an informed decision about the treatment…

Here, our experts tell you everything you need to know so you can make an informed decision about the treatment…

WHO WILL DEFINITELY BENEFIT FROM THESE DRUGS?

IF you are obese with a BMI of over 30 and another weight-related condition such as high blood pressure or type 2 diabetes, the strong evidence is that these medications could transform your health.

Roughly half of people taking semaglutide as a once-a-week injection in trials lost 10 per cent of their body weight – which they kept off during the four years of the trial.

One in five achieved 15 per cent weight loss, and one in 20 managed to shed a quarter of their weight.

But there are other life-­changing benefits. The drugs reduce the risk of heart attacks and strokes by 20 per cent, can prevent type 2 diabetes and protect against kidney disease.

They reduce blood pressure and cholesterol levels, and early ­studies even suggest they can lower the risk of ten out of 13 ­obesity-related cancers.

Side-effects from taking the drugs include nausea, vomiting, diarrhoea, constipation and ­pancreatitis.

However, obesity itself causes chronic disease and shortens lifespan – making these drugs a 'no brainer', says Prof Naveed ­Sattar, at the University of ­Glasgow. 'Ample evidence shows obesity can promote or accelerate over 200 diseases, including diabetes, strokes, many cancers, diseases like arthritis and mental health,' he says.

It is for this reason – that the benefits are considered to ­outweigh the known risks – that in 2023, the NHS approved Wegovy for those with a BMI over 30 and at least one weight-related health issue.

The drugs are also licensed as Ozempic to treat type 2 diabetes if standard drugs no longer work.

Trials show some people lose enough weight to put their ­diabetes into remission, and the drug can also reduce the risk of diabetes-related kidney disease.

ARE THERE BENEFITS IF OVERWEIGHT, NOT OBESE?

YES. While the drug is offered only to a select group of obese NHS patients, research shows that ­people who are overweight can greatly benefit, too.

Earlier this year, a trial of more than 17,000 adults with a BMI of 27 or over – which is considered overweight but not obese – ­concluded that they also lost on average 10 per cent of their body weight for as long as they stayed on the drug.

The participants – who were all over 45 and had previously ­suffered with a heart problem – were also significantly less likely to experience further heart issues. Experts say this is because any level of unhealthy weight increases the risk of life-threatening ­disease.

In 2017, researchers concluded that people with a BMI between 25 and 30 were nearly a third more likely to get heart disease, ­compared with those of a healthy weight. People with a BMI of more than 25 are also more at-risk of developing ­cancer, according to Cancer Research UK.

Private clinics are freely available to offer the drug to any patient they believe would benefit – regardless of their BMI.

There are also a number of online pharmacies which are selling the drug, but only to patients who meet a minimum criteria.

WHAT ABOUT NAUSEA AND OTHER SIDE-EFFECTS? 

IN trials, around a fifth of patients suffered from nausea, vomiting and diarrhoea and they're among the most common side-effects reported. It isn't clear why some people suffer badly and others don't, but it tends to coincide with starting the ­medication for the first time or upping the dose – and wears off as the body adjusts.

The drug slows down the body's metabolism, keeping food in the gut for longer, which may explain these problems, experts say.

'It's self-limiting and will resolve within a couple of weeks,' says Professor David Strain, from the University of Exeter.

Although trials haven't been done on people who are a normal weight, there is anecdotal evidence that they might be more at risk.

Dr Vicky Price, from the Society for Acute Medicine, says there has been a 'real increase' in the number of people misusing the drug coming to ­hospital with vomiting, diarrhoea and dehydration.

This is because the jab works by mimicking the 'hunger hormone' GLP-1, which is released by the stomach in response to eating and tells the brain it is full.

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People who are obese respond less well to this hormone when it is produced by the body naturally, which is why they keep eating.

But this synthetic version is at a much higher dose and stays in the body for longer, suppressing appetite. People of a normal weight, however, are already responding well to their natural GLP-1 hormones – getting a much larger dose than they need means they'll 'likely feel even more sick', Prof Strain says.

Most patients can avoid the worst effects by starting on a low dose and easing it up gradually, ­according to Prof Sattar.

To manage sickness, eat slowly and only if hungry, drink more ­fluids and choose healthy, non-processed foods.

ARE THEY RISKY IF CANCER RUNS IN THE FAMILY?

NOT for most people. The official Ozempic and Wegovy safety ­information states that patients with a family history of medullary thyroid cancer should not take the drug.

This is a type of tumour that forms inside the thyroid gland.

Early research suggested mice given the drug were more likely to get the disease.

There is no evidence that it raises the risk in humans.

However, as a precaution, the drugs' Danish ­manufacturer, Novo Nordisk, has warned that thyroid tumours could be a possible side-effect.

People with a rare condition called multiple endocrine neoplasia type 2, or MEN2, shouldn't take it either, as they have a genetic mutation which raises the risk of these types of cancer.

However, fewer than 2,000 people in the UK have MEN2.

'It's a minimal, theoretical risk,' Prof Strain says.

'But Novo ­Nordisk don't want to risk it.' For everyone else, early studies ­suggest taking the jabs will reduce your risk of ten out of 13 types of cancer known to be associated with excess weight, including colorectal, endometrial, kidney, liver and ovarian ­cancers.

CAN THEY REALLY MAKE YOU GO BLIND?

IT is unlikely. Earlier this month, a new study suggested that overweight patients taking ­semaglutide were more likely to develop a blindness condition called ­non-arteritic anterior ischemic optic neuropathy – or NAION.

However, the number of cases were still low. Out of nearly 1,000 patients taking the injections for weight loss, 20 experienced NAION, with many experiencing only temporary vision issues rather than permanent blindness.

Many experts are also sceptical of the findings.

'We have been using these drugs in diabetes patients for 17 years now and this condition has never been linked to them before,' says Prof Alex Miras, consultant ­endocrinologist and lecturer at Imperial College London.

'It's unlikely that we're suddenly seeing cases now.'

The researchers involved ­suggested it was possible that ­people who developed NAION may have had an underlying eye problem such as glaucoma.

For this reason, they suggested medics check whether their patients have any eye issues before they start the drug.

However, there are other serious semaglutide risks.

Pancreatitis, which may affect one in 100, causes inflammation of the pancreas, an organ in the abdomen which produces digestive hormones. This can become 'very serious and life-threatening' if not treated, says Dr Vicky Price.

Gallstones – tiny balls of cholesterol that form in the gallbladder – are an additional risk for anyone losing weight rapidly.

I KNOW THE RISKS BUT DO THEY WORK IF I'M THIN?

THE truth is we don't know. ­Clinical trials have not been ­performed on people who are a normal weight so we don't have evidence on how well it works and what the side-effects might be.

What we do know is that around 15 per cent of people fail to lose any significant weight on these drugs, which means you may take it, and put yourself at risk of side-effects, for nothing.

We all know about 'Ozempic face' – the gaunt, hollow-cheeked look caused by rapid fat loss in the face which has affected celebrities such as Sharon Osbourne.

But in addition, there's good evidence that this rapid weight loss (via any method, and not unique to Ozempic) also causes a dramatic drop in muscle mass, too.

Experts believe this could be dangerous, especially for older people, as a loss of muscle strength can increase the risk of falls.

'When you take these drugs, you will lose fat and muscle,' says Prof Miras. 'But, when you stop using them, you will likely gain the fat back, but not the muscle.'

However, perhaps most importantly, experts say there is a moral consideration for anyone thinking of taking these drugs.

A national shortage of semaglutide is expected to continue until 2025, according to NHS England.

'These are game-changing drugs for obese people, but we should not be encouraging people to take them just to look good for a ­wedding or on the beach,' says Prof Miras.