I lost three stone on Ozempic - but there are risks everyone should know about, writes JOHANN HARI

In the winter of 2022, the global pandemic seemed to be finally receding, so for the first time in two years I went to a party in London. I felt schlubby and slightly self-conscious, because I had hit 14 stone since the world shut down. 

The party was thrown by an Oscar-winning actor, and I was taken aback that nobody else had gained weight. Everyone looked like their own Snapchat filter. Their cheekbones were higher, their stomachs tighter. I bumped into an old friend and said to her, in a kind of shamed mumble, that I guessed everyone really did take up pilates in lockdown. She laughed and stared at me, stunned that I didn’t know what was really happening.

She pulled up on her iPhone a picture of a light blue plastic tube of Ozempic with a tiny needle sticking out of it. My weight has see-sawed several times in my life, from being slightly underweight to being obese. 

My first instinct was to resist Ozempic: I’ll go on my millionth diet and get there myself, I thought, without therisky option of drugs – even though I had to admit to myself it seemed to be getting harder as I aged. But there was a thought I couldn’t shake off. I realised that I had just become older than my grandfather ever got to be: he died of a heart attack at 44.

My dad has had serious heart problems that required surgery, and my uncle died of them. The science is clear that obesity makes it significantly more likely you will get heart disease, diabetes, cancer and dementia. It is, by some calculations, the biggest preventable cause of death.

Johann at 14 stone in 2022 vs. John after a year on Ozempic in 2024

So, reluctantly, I decided to try these drugs – paying £300 a month for them privately (although it is available on the NHS) – and at the same time do a deep dive into the science of them, spending a year interviewing over 100 experts and others all over the world, from Iceland to Minneapolis to Tokyo, who told me that we now have a new wave of drugs that produce a staggering amount of long-term weight loss.

In early 2023, two days after I first pricked myself with Ozempic, I opened my eyes and immediately felt that something was strange. Thwacking my alarm clock into silence, I lay there for five minutes, trying to figure out what it was. I felt very mildly nauseous, but it was not severe – if it had happened on a normal day, it wouldn’t have stopped me from doing anything. So it wasn’t that. 

It took me a while to realise what it was. I always wake up ravenously hungry, but on that morning I had no appetite at all. It was gone. 

I got out of bed and, on autopilot, went through my normal morning routine in North London. I left my flat and went to a local café run by a Brazilian woman named Tatiana, where my order is always the same: a large, toasted bread roll, filled with chicken and mayonnaise. 

As I sat there reading the newspapers, the food was placed in front of me and I looked at it. I felt like I was looking at a block of wood. I managed four bites and couldn’t eat any more. It felt like the shutters had come down on my appetite and now only tiny peeks of light could get through. I was about 80 per cent less hungry than I normally am, and went from eating 3,200 calories a day to around 1,800.

The sense of mild nausea kept stirring and passing, and it only fully went away after nearly a year. I lost three stone in those 12 months and my BMI went from obese (depicted in a menacing red on the NHS chart) to healthy (a lovely soothing green).

 We know that if you reverse obesity, you massively boost health. For example, after the dramatic weight loss of bariatric surgery, a study of more than 15,000 people found the chance of dying of coronary heart disease falls by 56 per cent, and risk of dying of cancer falls by 60 per cent. 

These effects are so dramatic that in the seven years after the operation, for people who had been severely obese, the chance of dying of any cause falls by 40 per cent. 

The evidence emerging from this research seems to be that both drugs and surgery are moving people in the same direction: one study found that they reduce risk of a heart attack or stroke by 20 per cent. I kept thinking of my grandfather and continued to jab myself. The weight was falling away so easily, it felt almost like magic.

But I kept asking myself: can it be so easy? Can you really get all these benefits without any side-effects? In the past, other weight-loss drugs were launched with comparable fanfare, but ended up having some unforeseen terrible effect on health that led to them being withdrawn. 

Most of the scientists I interviewed are confident that these new-generation drugs are broadly safe, because they have been used to treat diabetes for more than 15 years, without many negative effects – this is an important point. But from studying the science, I learned there are, in fact, several significant potential risks from these drugs – Ozempic, and the other drugs in the same class – that should be taken seriously.

During development it was discovered that when these drugs are given to rats, they are much more likely to develop thyroid cancer. So a group of French scientists began to investigate whether this might also be the case with humans. 

Jean-Luc Faillie is a professor of medical pharmacology and toxicology at the University Hospital of Montpellier. He explained to me that France has one of the largest medical databases in the world, so they went back and analysed the data for all the patients with type 2 diabetes who had taken these drugs for one to three years between 2006 and 2018. They then compared those patients to a sample of diabetics who had not taken them.

Their findings were startling.

He said, ‘We show there is an increased risk of about 50 to 75 per cent of developing thyroid cancer.’ He told me it’s important not to misread this. It doesn’t mean that if you take the drug, you have a 50 to 75 per cent chance of developing thyroid cancer; it means that if you take the drug, your chances will be 50 to 75 per cent higher than if you had not taken it. Overall, the risk remains small, even if you are on these drugs.

Nonetheless,  Professor Faillie added, ‘In epidemiology in general, when you have a 50 per cent increase, it’s quite a thing.’ When I put these concerns to the companies making the drugs, they pointed out that the European Medicines Agency has not been persuaded by this evidence.

Other experts voiced concerns. Some are worried about the effects on pregnant women because animal studies produced birth abnormalities. Others are disturbed that people often lose a lot of muscle mass on these drugs and, if that happens, you can become less mobile as you age, and are more likely to be injured if you fall. Others still are concerned that people taking these drugs can eat so little that they develop malnutrition.

The more I looked, the more I realised there are no simple answers here. You have to compare the potentially serious risks of taking these drugs with the dangers of continuing to be obese. For example: the drugs may pose a risk of increased thyroid cancer, but ongoing obesity poses a strong risk of an increase of developing many different types of cancer.

Some of my friends kept asking me: why not choose the less risky third option, of losing weight by dieting and exercising instead? We all know people for whom this has worked. But when I looked at the science, I learned that the truth is they are a small minority.

Sharon Osbourne lost 42lb through the drug

Professor Traci Mann at the University of Minnesota has carried out some of the most detailed research into diets and found that, after two years of starting a diet, you will, on average, weigh two pounds less than you did at the start. ‘It seems that they work for the initial weight loss, and then back on it comes,’ she told me. Other scientists explained why. 

When you diet, your metabolism slows down and you crave fattier and more sugary foods. Professor Giles Yeo, an obesity researcher at the University of Cambridge, said, ‘Your brain hates it when you lose weight. It will drag you kicking and screaming back up to where you were.’ I had felt like such a failure for losing my own personal diet wars, but it turns out I was entirely typical.

So here we are, facing an unsavoury choice. It doesn’t have to be this way for our kids and future generations. There are big changes we could make now to prevent them facing this dilemma, and I saw how they have been put into place in countries such as Japan, where there is little obesity. 

We could make sure all children have fresh, nutritious food at school, for a start. But it will take time, leaving many of us trapped with this hard decision.

After a year of investigating the risks, my weight has stabilised, and I have decided to continue taking Ozempic. Because most people regain the weight they have lost when they stop, I plan to continue taking it for the foreseeable future. 

But I’m 45, I don’t have thyroid cancer in my family and there’s no chance of getting pregnant. Others will have to weigh the many competing risks for themselves and come to their own conclusions.

Anyone who says that this is simple or there’s an obvious choice that’s right for everyone is not being honest. We need to recognise the complexity of the situation we find ourselves in. These drugs are not a magic solution, nor are they a magic trick. They are a trapdoor for people who are stuck in a trap, unable to see any other way out. Every escape route comes with a risk, but so does staying trapped in obesity for ever. I have made my choice. Now every other overweight person is going to have to make theirs.

How Ozempic adds up

$556 billion: The 2023 market value of Novo Nordisk, the Danish company that makes Ozempic. Denmark’s GDP was $400 billion last year.

$13.9 billion: The amount made from Ozempic sales in 2023 (66% of it was in the US).

27.8%: The proportion of the British population who are obese.

15%: The average bodyweight loss after a year. 

£6.5 BILLION: How much the UK spends every year treating obesity-related conditions.

Magic Pill by Johann Hari will be published on 2 May (Bloomsbury, £20). To order a copy for £17 until 5 May, go to mailshop.co.uk/books or call 020 3176 2937. Free UK delivery on orders over £25.