The risks of taking Ozempic that are only now emerging and make me worry, by DR EMILY LEEMING

Should you, would you, take Ozempic? It’s a question I’m asked by friends and it’s a hot topic among my scientist colleagues, too. The answer is complicated.

Ozempic has been touted as a new, miracle weight-loss fix that can help those who have battled to shed pounds for years successfully lose weight with a single weekly injection.

The jab contains a drug called semaglutide, originally developed to help manage type 2 diabetes, assisting the body in making more of the hormone insulin and so keeping blood sugar levels in check. Then it was noticed that there was a side-effect –weight loss. The rest, as they say, is history. The drug has been in such demand that shortages have been reported worldwide.

The weight loss occurs as semaglutide mimics the effect of the fullness hormone GLP-1 that’s naturally produced in your gut when you eat, signalling to your brain that you are full. 

The appeal of this synthetic version of GLP-1 is it’s longer-lasting and more potent because it’s not broken down quickly in the body, hence it can be taken as a weekly injection. Not only will it cut your appetite but it will also slow the movement of food through the gut, meaning you feel fuller for longer.

Other GLP-1 agonists that work like semaglutide have suggested that they can significantly alter the gut microbiome, reducing microbial diversity

For most people, this leads to significant weight loss – and here is my first ‘but’, as even this ‘miracle’ fix won’t work for everyone.

What’s more, it’s worth noting that its success still hinges on eating fewer calories than you need – without this, it won’t work. 

In a trial, published in 2022 in the journal Nature, 152 participants with a BMI of 27 (which is overweight – 30 or more is obese) and above took semaglutide for two years (alongside a reduced calorie diet and monthly support from a dietitian, as well as being encouraged to do at least 150 minutes of exercise a week) and lost on average 15 per cent of their body weight, compared with 3 per cent loss in a placebo group.

Impressive figures, yes, but while the study showed 77 per cent of participants lost at least 5 per cent of their original weight (thought to lead to benefits such as improved blood sugar levels, lower blood pressure and less strain on the heart), 23 per cent didn’t achieve this crucial 5 per cent weight loss. 

And for context, losing 5 per cent of your body weight is about the amount achieved by calorie counting or more traditional dieting across a two-year period, according to a 2008 study published in the New England Journal of Medicine.

Then there are the side-effects, which commonly include nausea, vomiting, diarrhoea and constipation (as semaglutide slows the passage of food through the gut). For some, these can be bad enough to make it difficult to lead life as normal, even to leave the house. I get asked a lot whether the drug could damage the gut microbiome (the community of microbes that lives in your gut and plays a role in so many different elements of your health). 

We know that many medications interact with the gut microbiome. For example, a 2018 study published in Nature found that about a quarter of over 1,000 commonly used drugs (and that’s not including antibiotics) can affect the gut bacteria, though not all in a negative way. (Some may actually reduce levels of harmful bacteria.)

Regarding semaglutide, there’s a lot we’ve yet to find out. A handful of studies on other GLP-1 agonists that work like semaglutide have suggested that they can significantly alter the gut microbiome, reducing microbial diversity (and diversity is beneficial for our health).

Dr Emily Leeming says, ‘Semaglutide is a serious drug, far from the easy option it’s made out to be. It isn’t for thin people looking to shed a few pounds’

Ozempic has been touted as a new, miracle weight-loss fix that can help those who have battled to shed pounds for years successfully lose weight with a single weekly injection

Specifically on semaglutide, earlier this year a study in mice published in the journal Biochemical and Biophysical Research Communications, suggested the opposite, that the drug increased levels of certain ‘good’ gut bacteria and supported the health of the gut barrier lining. However, I must emphasise that findings from mice don’t always translate to humans, and, as yet, barely any research has looked into this.

While the future of semaglutide seems hopeful, it’s been on the market only since 2017 and not enough time has passed to know for sure what it does long-term, though it does seem safe for now.

There have been weight-loss drugs before, though many, such as the amphetamine-based fen-phen and Meridia – heralded as the next miracle thing only to be withdrawn for having dangerous side-effects – have fallen at the last hurdle, when problems emerged in the long term.

But my point is that semaglutide comes with side-effects – some of which we know about, some we may yet discover. We should reserve this drug for those who really need it, those who are in the obese BMI category, 30 and above. For some of them, the drug could be potentially life-saving.

In the UK, the national guidelines recommend that it can be prescribed for people who have a BMI of 35 or higher and at least one weight-related health condition, such as raised cholesterol or type 2 diabetes (or a BMI of 32.5 for people from South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean backgrounds – who are often more at risk of weight-related health conditions) as part of a specialist weight management service, alongside a low-calorie diet and exercise. 

It can also be prescribed to people with a BMI between 30 and 34.9 if they meet specific criteria.

I welcome this as an alternative option for those whose weight problems are endangering their health. We have to acknowledge that, for most people, losing weight is hard.

It isn’t just about moving more and eating less; there are complex genetic and environmental reasons why someone might be bigger than the next person. Even your gut microbiome may play a role, as some people’s bacteria can be more efficient at harvesting energy from food than that of others.

Some people have health conditions or take medication that mean they’re more likely to gain weight, too. The human body is hard-wired against weight loss, likely a necessity for survival in our caveman days through periods of famine.

If you have been prescribed semaglutide and are experiencing the side-effects, it might help to try eating smaller meals more often, and taking the standard advice for nausea, sipping peppermint or ginger tea, and staying hydrated if you experience vomiting or diarrhoea.

Longer-term, it’s important to remember that once you stop taking it (and currently prescriptions can be issued for only two years) your hunger signals return to normal, so the weight can pile back on within a matter of months, which is why retraining your eating habits – alongside taking the drug – is so key.

Semaglutide is a serious drug, far from the easy option it’s made out to be. It isn’t for thin people looking to shed a few pounds.