Given the glowing reports about the “miracle” weight loss effects that Wegobi and Ozempic have received so far, one would be forgiven for thinking they were a cure for any ailment.
Originally developed to treat type 2 diabetes, the drug has transformed the lives of diabetics and has also become a global panacea for obesity sufferers.
A-list celebrities are said to be swearing by it to stay slim and glowing, headlines say it can improve heart health, and, if the anecdotes are true, it may even curb addictive behaviors like gambling, smoking and excessive drinking.
But like any drug, there is a flip side.
A study earlier this month showed that the active ingredient in both drugs, semaglutide, was linked to an increased risk of the blinding disease.
Emergency medicine experts also warned that there has been a “real increase” in the number of people visiting hospital with complications related to the drug, such as nausea and vomiting.
But how significant are these risks really? And if you’re interested in taking it yourself, how can you tell if it will really help you? Here, experts tell you all the information you need to make an informed decision about your treatment…
Here, our experts will tell you everything you need to know so you can make an informed decision about your treatment.
Who would certainly benefit from these drugs?
If you are obese, meaning your BMI is over 30, and have weight-related conditions such as high blood pressure or type 2 diabetes, there is strong evidence that these drugs may improve your health.
About half of the people in the trial who took semaglutide as a once-weekly injection lost 10 percent of their body weight and maintained that weight over the four-year study period.
One in five people lost 15 percent of their body weight, and one in 20 people lost a quarter of their body weight.
But there are other life-changing benefits too: the drug can reduce the risk of heart attack and stroke by 20%, prevent type 2 diabetes, and prevent kidney disease.
They lower blood pressure and cholesterol levels, and early studies suggest they may also lower the risk of 10 of the 13 obesity-related cancers.
Side effects of taking the medication include nausea, vomiting, diarrhea, constipation, and pancreatitis.
But because obesity itself causes chronic disease and shortens lifespan, these drugs are the “obvious choice”, says Prof Naveed Sattar, from the University of Glasgow. “Sufficient evidence shows that obesity can promote or accelerate more than 200 diseases, including diabetes, stroke, many cancers, diseases such as arthritis and mental disorders,” he says.
For this reason – that the benefits are believed to outweigh the known risks – the NHS has approved Wegovy in 2023 for people with a BMI over 30 and at least one weight-related health problem.
The drugs are also approved as “Ozempic” to treat type 2 diabetes when standard medications no longer work.
Clinical trials have shown that some people lost enough weight to put their diabetes into remission, and the drug can also reduce the risk of diabetes-related kidney disease.
If you are overweight but not obese, are there benefits?
Yes. The drug is only available to the NHS obese patient population, but research has shown that people who are overweight can also benefit greatly.
Earlier this year, a trial of more than 17,000 adults with a BMI of 27 or above (considered to be overweight but not obese) concluded that people lost an average of 10% of their body weight while taking the drug.
The participants, all over 45 and with pre-existing heart disease, were also significantly less likely to develop recurrent heart disease — because experts say any level of unhealthy weight increases the risk of life-threatening diseases.
In 2017, researchers concluded that people with a BMI between 25 and 30 are nearly a third more likely to develop heart disease than those at a healthy weight. People with a BMI above 25 also have a higher risk of developing cancer, according to Cancer Research UK.
Private clinics are free to offer the drug to any patient they believe would benefit, regardless of BMI.
There are also many online pharmacies that sell the drug, but only to patients who meet minimum criteria.
What about nausea and other side effects?
In clinical trials, about a fifth of patients suffered from nausea, vomiting, and diarrhea, which were among the most common side effects reported. It’s not clear why some suffer so much and others so little, but these symptoms tend to appear together when people first start taking the drug or when their dose is increased, and then go away as their body adjusts.
Experts say these problems may occur because the drug slows the body’s metabolism, keeping food in the intestines longer.
“This is a self-limited condition that should resolve within a few weeks,” said Prof David Strain, from the University of Exeter.
No studies have been done in normal weight people, but there is anecdotal evidence that normal weight people may be at greater risk.
Dr Vicky Price, from the Society of Emergency Medicine, said there had been a “real increase” in the number of people misusing the drug and presenting to hospital with vomiting, diarrhoea and dehydration.
This is because the injections work by mimicking the “hunger hormone” GLP-1, which is released by the stomach in response to a meal and tells the brain you feel full.
Obese people continue to eat because they have a weaker response to this hormone, which is produced naturally in the body.
But the synthetic version is given in much higher doses and stays in the body for longer, suppressing appetite – but normal-weight people already respond well to the natural GLP-1 hormone, and taking a much higher dose than they need “is likely to make them feel even worse”, says Strain.
Most patients can avoid the worst effects by starting with a small amount and gradually working their way up, Sutter said.
To manage the disease, eat slowly and only when you are hungry, drink plenty of fluids and choose healthy, unprocessed foods.
Am I at risk if I have a family history of cancer?
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 drugs.
This is a type of tumor that forms in the thyroid gland.
Early studies suggest that mice given the drug are more likely to get the disease.
There is no evidence that it poses an increased risk to humans.
But as a precaution, the drug’s Danish manufacturer, Novo Nordisk, has warned that thyroid tumours are a possible side effect.
Patients with a rare disease called multiple endocrine neoplasia type 2 (MEN2) should also not take the drug because a genetic mutation that puts them at higher risk of this type of cancer.
However, there are fewer than 2,000 cases of MEN2 in the UK.
“This is the theoretically minimal risk,” Prof Strain said.
“But Novo Nordisk doesn’t want to take any risks.” For everyone else, early studies suggest that vaccination reduces the risk of 10 of 13 types of cancer known to be associated with excess weight, including colorectal, endometrial, kidney, liver and ovarian cancer.
Can they really make you blind?
That’s unlikely. Earlier this month, a new study suggested that overweight patients taking semaglutide were more likely to develop a blinding condition called non-arteritic anterior ischemic optic neuropathy (NAION).
But the number of cases is still small: Of about 1,000 patients who received injections for weight loss, 20 experienced NAION, and most of those only experienced temporary vision impairment rather than permanent blindness.
Many experts are also skeptical of the findings.
“We’ve been using these drugs in diabetic patients for 17 years and there has never been a link between the disease and these drugs,” says Professor Alex Milas, a consultant endocrinologist and lecturer at Imperial College London.
“It’s unlikely that we’re suddenly going to start seeing cases now.”
The researchers suggested that people who developed NAION may have had underlying eye diseases such as glaucoma.
For this reason, doctors recommended checking patients for any eye problems before administering the drug.
However, semaglutide has other significant risks.
Pancreatitis, which can affect one in 100 people, causes inflammation of the pancreas, an organ in the abdomen that secretes digestive hormones, and can become a “very serious and life-threatening” condition if left untreated, says Dr Vicky Price.
Gallstones (small clumps of cholesterol that form in the gallbladder) are an additional risk for people who have lost weight rapidly.
I know the risks, but will it still be effective if I’m skinny?
The truth is, we don’t know. There have been no clinical trials in normal weight people, so there’s no evidence of how effective it is or what the side effects might be.
What we do know is that about 15 percent of people fail to lose significant weight on these drugs, meaning taking them and risking side effects may be futile.
We all know about “Ozempic face,” the gaunt, sunken appearance caused by a rapid loss of facial fat that affects celebrities like Sharon Osbourne.
But there’s also strong evidence that this rapid weight loss (from any method, not just Ozempic) also causes a dramatic loss of muscle mass.
Experts believe this could be especially dangerous for older people, as reduced muscle strength can increase the risk of falling.
“When you take these drugs, you lose fat and muscle,” says Professor Milas, “but when you stop taking them, the fat will likely come back, but the muscle will not.”
But perhaps most importantly, experts say there are moral considerations for anyone considering taking these drugs.
According to NHS England, the national shortage of semaglutide is expected to last until 2025.
“These are breakthrough drugs for obese people, but people shouldn’t be encouraged to take them just to look good for the wedding or the beach,” Prof Milas said.
