How do you know if Ozempic is right for you: how likely you are to experience side effects, the risks – and whether it will really work. Read our special report
Given the breathtaking coverage of Wegovy and Ozempic’s “miraculous” weight loss efforts, you’d almost think they were a cure-all.
Originally designed to treat type 2 diabetes and transform the lives of people with the condition, they have now become a global wonder drug for people with obesity.
A-list celebrities reportedly swear by them to keep them slim and shiny. Headlines suggest they can improve your heart health. And if the anecdotes are true, they could even curb addictive behaviors like gambling, smoking and drinking too much alcohol.
But as with any medicine, there is a downside.
A study earlier this month found that the active ingredient in both drugs, semaglutide, is linked to an increased risk of a condition that causes blindness.
Experts from the Society for Acute Medicine also warn of a “real increase” in the number of people ending up in hospital with complications such as nausea and vomiting linked to the drugs.
But how big are these risks really? And if you’re curious about taking them yourself, how can you tell if they’ll really benefit you? 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 treatment…
WHO WILL DEFINITELY BENEFIT FROM THESE MEDICINES?
IF you are obese (a BMI of over 30) and also have another weight-related condition, such as high blood pressure or type 2 diabetes, there is strong evidence that these medicines can improve your health.
About half of the people who received semaglutide as a once-weekly injection in studies lost 10 percent of their body weight — and kept it off over the four years of the study.
One in five achieved a 15 percent weight loss, and one in twenty 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. Previous studies have even shown that they can reduce the risk of ten of the thirteen obesity-related cancers.
Side effects of the drugs include nausea, vomiting, diarrhea, constipation, and pancreatitis.
But obesity itself causes chronic disease and shortens lifespan, making these drugs a ‘no brainer’, says Prof Naveed Sattar from the University of Glasgow. ‘Extensive evidence shows that obesity can promote or accelerate over 200 diseases, including diabetes, stroke, many cancers, conditions such as arthritis and mental health,’ he says.
For this reason – because the benefits are considered to outweigh the known risks – the NHS approved Wegovy in 2023 for people with a BMI over 30 and at least one weight-related health problem.
The drugs are also approved under the name Ozempic for the treatment of type 2 diabetes when standard medications no longer work.
Research shows that some people lose enough weight to clear their diabetes. In addition, the drug may reduce the risk of diabetes-related kidney disease.
ARE THERE BENEFITS TO BEING OVERWEIGHT, AND NOT OBESITY?
YES. Although 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 study of more than 17,000 adults with a BMI of 27 or higher (which is overweight but not obese) found that they also lost an average of 10 percent of their body weight while they continued taking the drug.
The participants – all of whom were over 45 and had previously suffered from a heart condition – were also significantly less likely to develop heart problems again. Experts say this is because any level of unhealthy weight increases the risk of life-threatening diseases.
In 2017, researchers found that people with a BMI between 25 and 30 were almost a third more likely to develop heart disease, compared with people of a healthy weight. People with a BMI over 25 are also more likely to develop cancer, according to Cancer Research UK.
Private clinics are free to offer the drug to any patient they think would benefit from it, regardless of their BMI.
There are also a number of online pharmacies that sell the drug, but only to patients who meet certain minimum criteria.
WHAT ABOUT NAUSEA AND OTHER SIDE EFFECTS?
In trials, about a fifth of patients experienced nausea, vomiting and diarrhoea, and these are the most common side effects reported. It’s not clear why some people suffer badly and others don’t, but they usually coincide with first starting the drug or increasing the dose – and go away as the body adjusts.
According to experts, the drug slows down the body’s metabolism, causing food to stay in the intestines longer. That could explain these problems.
“It’s a self-limiting problem that goes away within a few weeks,” says Professor David Strain of the University of Exeter.
Although no studies have been done in normal-weight people, there is anecdotal evidence that they may be at greater risk.
According to Dr Vicky Price of the Society for Acute Medicine, there has been a “real increase” in the number of people abusing the drug and ending up in hospital with vomiting, diarrhoea and dehydration.
This is because the shot works by mimicking the hunger hormone GLP-1, which is released by the stomach in response to food and signals to the brain that it is full.
People who are obese respond less well to this hormone when the body produces it itself. That is why they keep eating.
But this synthetic version has a much higher dose and stays in the body longer, suppressing appetite. However, normal-weight people already respond well to their natural GLP-1 hormones – a much higher dose than they need means they are ‘likely to feel even sicker’, says Prof Strain.
According to Prof. Sattar, most patients can avoid the worst effects by starting with a low dose and gradually increasing it.
To control illness, eat slowly and only when you are hungry. Also, drink more fluids and choose healthy, unprocessed foods.
ARE THEY RISKY IF CANCER RUNS IN THE FAMILY?
NOT 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 in the thyroid gland.
Previous research showed that mice given the drug were more likely to develop the disease.
There is no evidence that this increases the risk in humans.
As a precaution, the Danish manufacturer of the drugs, Novo Nordisk, has warned that thyroid tumors could be a possible side effect.
People with a rare condition, multiple endocrine neoplasia type 2 (MEN2), should also not take the drug because they have a genetic mutation that increases the risk of this type of cancer.
However, fewer than 2,000 people in the UK have MEN2.
“It’s a minimal, theoretical risk,” says Professor Strain.
‘But Novo Nordisk doesn’t want to take the risk.’ For everyone else, early studies suggest that getting the jabs reduces the risk of 10 of the 13 cancers linked to being overweight, including colorectal, uterine, kidney, liver and ovarian cancers.
CAN THEY REALLY MAKE YOU BLIND?
IT’S unlikely. Earlier this month, a new study suggested that obese patients taking semaglutide were more likely to develop a blinding condition called non-arteritic anterior ischemic optic neuropathy – or NAION.
However, the number of cases was still low. Of the nearly 1,000 patients who received the injections to lose weight, 20 experienced NAION, with many experiencing only temporary vision problems rather than permanent blindness.
Many experts are also skeptical about the findings.
“We have been using these drugs in diabetes patients for 17 years, but this condition has never been linked to diabetes before,” said Prof Alex Miras, an endocrinologist and lecturer at Imperial College London.
“It is unlikely that we will suddenly see cases now.”
The researchers involved suggested that it was possible that people who developed NAION had an underlying eye problem, such as glaucoma.
Therefore, they advise doctors to check if their patients have eye problems before starting the drug.
However, there are other serious risks associated with semaglutide.
Pancreatitis, which can affect one in 100 people, causes inflammation of the pancreas, an organ in the abdomen that produces digestive hormones. This can become “very serious and life-threatening” if left untreated, says Dr Vicky Price.
Gallstones – small balls of cholesterol that form in the gallbladder – pose an additional risk for anyone who loses weight quickly.
I KNOW THE RISKS, BUT WILL THEY WORK IF I’M THIN?
THE truth is, we don’t know. There have been no clinical trials done on normal weight people, so we have no evidence about how well it works and what the side effects might be.
What we do know is that about 15 percent of people do not lose significant weight on these medications. This means that you may be taking the medication for nothing and therefore risking side effects.
We’re all familiar with the “Osmpic face”: the gaunt, hollow cheeks created by rapid fat loss in the face that has affected celebrities like Sharon Osbourne.
In addition, there is good evidence that this rapid weight loss (by any method, and not just Ozempic) also causes a dramatic decrease in muscle mass.
Experts believe this can be dangerous, especially for older people, as loss of muscle strength can increase the risk of falls.
‘If you take these drugs, you lose fat and muscle,’ says Prof Miras. ‘But if you stop taking them, you probably gain the fat back, but not the muscle.’
But perhaps even more importantly, experts say there are moral considerations for anyone considering using these drugs.
According to NHS England, the national shortage of semaglutide is expected to continue until 2025.
“These are groundbreaking drugs for overweight people, but we should not encourage people to take them just to look good at a wedding or on the beach,” said Professor Miras.
