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Judging by the impressive coverage that the “miracle” weight-loss injections Wegovy and Ozempic have received so far, you might think they are the cure-all for everything.
Originally designed to treat type 2 diabetes – and transforming the lives of those living with the disease – they have also become a global panacea for people with obesity.
A-list celebrities are said to swear by these products for keeping them slim and glowing. Headlines suggest they can improve heart health. And if the anecdotes are true, they could even curb addictive behaviors like gambling, smoking and binge drinking.
But, as with any drug, it also has its downside.
A study earlier this month linked the active ingredient in both drugs, semaglutide, to an increased risk of developing a blinding disease.
Experts at the Society for Acute Medicine have also warned of a “real increase” in the number of people attending hospital with complications such as nausea and vomiting related to medication.
But how significant are these risks really? And, if you’re curious about taking it yourself, how can you know if it will actually benefit you? Here, 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 treatment…
WHO WILL DEFINITELY BENEFIT FROM THESE MEDICINES?
If you are obese, have a BMI over 30, and have another weight-related condition, such as high blood pressure or type 2 diabetes, there is strong evidence that these drugs could transform your health.
About half of the people taking semaglutide as an injection once a week in the trials lost 10 percent of their body weight, which they kept off over the four years the trial lasted.
One in five achieved a 15 percent weight loss, and one in 20 managed to lose a quarter of their weight.
But there are other life-changing benefits. The drugs reduce the risk of heart attacks and strokes by 20 percent, can prevent type 2 diabetes and protect against kidney disease.
They lower blood pressure and cholesterol levels, and early studies even suggest they may reduce the risk of ten out of thirteen obesity-related cancers.
Side effects of taking these medications include nausea, vomiting, diarrhea, constipation, and pancreatitis.
However, obesity itself causes chronic disease and shortens life expectancy, so such drugs are a “no-brainer”, says Professor Naveed Sattar, from the University of Glasgow. “There is ample evidence to show that obesity can promote or accelerate more than 200 diseases, including diabetes, stroke, many types of cancer, diseases such as arthritis and mental health problems,” he says.
It is for this reason (with the benefits 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 problem.
Drugs such as Ozempic are also approved to treat type 2 diabetes if standard medications no longer work.
Trials show that some people lose enough weight to put their diabetes into remission, and the drug may also reduce the risk of diabetes-related kidney disease.
ARE THERE BENEFITS IF I AM OVERWEIGHT AND NOT OBESE?
YES. While the drug is only offered to a select group of obese NHS patients, research shows that overweight people can also benefit greatly from it.
Earlier this year, a trial of more than 17,000 adults with a BMI of 27 or higher (considered overweight but not obese) found that they also lost an average of 10 percent of their body weight while taking the drug.
The participants, who were over 45 and had previously suffered a heart problem, were also significantly less likely to suffer further heart problems. Experts say this is because any unhealthy weight level increases the risk of potentially life-threatening diseases.
In 2017, researchers concluded that people with a BMI between 25 and 30 were almost a third more likely to suffer from heart disease, compared with those who were a healthy weight. People with a BMI over 25 are also at higher risk of developing cancer, according to Cancer Research UK.
Private clinics are available to offer the drug free of charge to any patient they feel would benefit, regardless of their BMI.
There are also several online pharmacies that sell the drug, but only to patients who meet minimum criteria.
WHAT ABOUT NAUSEA AND OTHER SIDE EFFECTS?
In the trials, around a fifth of patients suffered nausea, vomiting and diarrhoea, and these are some of the most common side effects. It is not clear why some people suffer a lot and others do not, but it usually coincides with starting treatment for the first time or increasing the dose, and goes away as the body adapts.
The drug slows the body’s metabolism, keeping food in the gut for longer, which could 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 no trials have been conducted in people of normal weight, there is anecdotal evidence that they may be at higher 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 and arriving at hospital with vomiting, diarrhoea and dehydration.
This is because the vaccine works by mimicking the “hunger hormone” GLP-1, which is released by the stomach in response to food and tells the brain that it is full.
Obese people respond less well to this hormone when the body produces it naturally, so they continue to eat.
But this synthetic version is found in much higher doses and stays in the body for longer, suppressing appetite. However, people of normal weight are already responding well to their natural GLP-1 hormones; receiving a much higher dose than they need means they will “probably feel even sicker”, says Professor Strain.
Most patients can avoid the worst effects by starting with a low dose and gradually increasing it, according to Professor Sattar.
To control the disease, eat slowly and only when you are hungry, drink more fluids and choose healthy, unprocessed foods.
ARE THEY RISKY IF CANCER RUNS IN THE FAMILY?
NOT suitable for most people. The official safety information for Ozempic and Wegovy states that patients with a family history of medullary thyroid cancer should not take the drug.
This is a type of tumor that forms inside the thyroid gland.
Early research suggested that mice given the drug were more likely to contract the disease.
There is no evidence that it increases the risk in humans.
However, as a precaution, the drug’s Danish manufacturer, Novo Nordisk, has warned that thyroid tumors could be a possible side effect.
People with a rare disease called multiple endocrine neoplasia type 2, or MEN2, should also not take it because they have a genetic mutation that increases their risk of developing this type of cancer.
However, fewer than 2,000 people in the UK have MEN2.
“It’s a minimal and theoretical risk,” says Professor Strain.
“But Novo Nordisk doesn’t want to take that risk.” For everyone else, early studies suggest that getting vaccinated will reduce the risk of ten of the 13 cancers known to be associated with excess weight, including colorectal, endometrial, kidney, liver and ovarian cancers.
CAN THEY REALLY MAKE YOU BLIND?
It’s unlikely. Earlier this month, a new study suggested that overweight patients taking semaglutide were more likely to develop a potentially blinding condition called non-arteritic anterior ischemic optic neuropathy (NAION).
However, the number of cases remains low. Of the nearly 1,000 patients who received weight-loss injections, 20 suffered from NAION, and many of them only experienced temporary vision problems rather than permanent blindness.
Many experts are also skeptical of the results.
“We have been using these drugs in patients with diabetes for 17 years and the condition has never been linked to them before,” says Professor Alex Miras, consultant endocrinologist and professor at Imperial College London.
“It’s unlikely that we’ll suddenly be 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 that doctors check whether their patients have any eye problems before starting the drug.
However, there are other serious risks of semaglutide.
Pancreatitis, which can affect one in 100 people, causes inflammation of the pancreas, an organ in the abdomen that produces digestive hormones. The condition can be “very serious and potentially fatal” if left untreated, says Dr Vicky Price.
Gallstones (small balls of cholesterol that form in the gallbladder) are an additional risk for anyone who loses weight rapidly.
I KNOW THE RISKS, BUT DO THEY WORK IF I’M THIN?
The truth is that we don’t know. There have been no clinical trials on people of normal weight, so we have no evidence of its effectiveness or possible side effects.
What we do know is that about 15 percent of people fail to lose significant weight on these drugs, meaning they may be taking them and risking side effects for nothing.
We’re all familiar with “Ozempic face,” the gaunt, sunken-cheeked appearance caused by rapid loss of facial fat that has plagued celebrities like Sharon Osbourne.
But there is also good evidence that this rapid weight loss (via any method, not just Ozempic) also causes a dramatic drop in muscle mass.
Experts believe this could be dangerous, especially for older people, as loss of muscle strength can increase the risk of falls.
“When you take these drugs, you lose fat and muscle,” says Professor Miras. “But when you stop taking them, you are likely to regain the fat, but not the muscle.”
Most importantly, however, experts say there is a moral consideration for anyone considering taking these drugs.
National shortages of semaglutide are expected to continue until 2025, according to NHS England.
“These are potentially game-changing drugs for obese people, but we shouldn’t be encouraging people to take them just to look good at a wedding or on the beach,” says Professor Miras.