Jeremy Clarkson reveals the unexpected ways the popular weight loss jab has affected him beyond shedding pounds.

Jeremy Clarkson has revealed that he has lost three stone after using the weight-loss medication Mounjaro, while admitting that the treatment has also brought a number of unexpected side effects.

The Clarkson’s Farm presenter said the once-a-week injection helped him slim down over a six-month period, although his progress has recently slowed. Speaking in a new interview, Clarkson described the results as significant, but also said he had noticed changes in his mood, concentration and even his shoe size.

The 65-year-old broadcaster, best known for Top Gear, The Grand Tour, Who Wants To Be A Millionaire? and Clarkson’s Farm, has spoken openly in recent years about his health and lifestyle. His latest comments come as medications such as Mounjaro have become a major talking point in conversations around weight management.

Clarkson said the treatment had helped him become more active, allowing him to walk further and take his dogs out for longer periods. Despite his typically dry humour, he suggested the health benefits had been noticeable.

He joked that he was now closer to looking like model David Gandy than he had been a year earlier, though only by a very small margin. But behind the joke was a more serious point: Clarkson said he feels healthier than before and is able to do more physically.

However, he also said the experience has not been entirely straightforward. While discussing his work on Who Wants To Be A Millionaire?, Clarkson suggested that he has sometimes felt less mentally sharp while using the medication.

He described moments on set when he later realised he could have responded differently, but only after the moment had passed. At the same time, he admitted it was difficult to know whether the medication was responsible, or whether the same thing might have happened anyway.

That uncertainty runs through much of Clarkson’s account. He addressed several possible side effects with characteristic humour, including changes in digestion and personal health, while making clear that not every change can be easily linked to one cause.

One of the most unusual details involved his feet. Clarkson said shoes that had fitted him the previous year were now becoming loose, joking that he may be the first person to lose weight from his feet.

The comment quickly drew attention because it was both unexpected and recognisably Clarkson. His public image has long been built on blunt remarks, self-deprecating jokes and turning personal updates into comic observations. But the wider subject is serious, as more people consider weight-loss injections and ask what side effects may come with them.

Mounjaro, known generically as tirzepatide, was originally developed for the treatment of type 2 diabetes. It works by imitating two naturally occurring hormones, GLP-1 and GIP, which help regulate blood sugar and appetite. In recent years, it has also been used more widely for weight management in adults who meet medical criteria.

Doctors have repeatedly warned that these treatments should be used with professional guidance. They are not simple cosmetic products, and they can affect the body in different ways depending on the person’s health, dose and medical history.

Dr Angela Kwong, a GP with an interest in obesity management, has explained that Mounjaro is approved in some countries for type 2 diabetes, weight management in adults with obesity or weight-related health conditions, and in some cases obesity-related obstructive sleep apnoea.

She said the most common side effects are gastrointestinal, including nausea, vomiting, constipation, bloating, diarrhoea and reduced appetite. These effects are often mild and may improve as the body adjusts, although experiences vary between individuals.

Clarkson said he has not experienced every side effect commonly associated with the medication. Instead, his own account focused more on changes that he found surprising or difficult to interpret, such as his concentration and physical changes beyond the expected weight loss.

His comments are likely to add to public discussion around weight-loss injections, particularly because Clarkson’s audience reaches far beyond health and lifestyle circles. His farming series has introduced him to a new generation of viewers, while his long television career means his personal updates often attract widespread attention.

The timing is also notable. Clarkson is preparing for the next season of Clarkson’s Farm, with fans eager to see how life at Diddly Squat continues after a period marked by bad weather, animal health concerns, business pressures and fresh farming challenges.

The programme has increasingly shown a more vulnerable side of Clarkson, especially when dealing with the physical and emotional strain of farm life. His latest health comments fit into that broader picture of a presenter who remains outspoken and humorous, but is also more willing to discuss the realities of ageing, fitness and personal change.

For Clarkson, the overall verdict appears to be cautiously positive. He says the medication has helped him lose weight and feel healthier, even if the process has included odd and sometimes confusing side effects.

As public interest in Mounjaro continues to grow, his experience may resonate with many people who are curious about the treatment but unsure what it can feel like in everyday life. Clarkson’s account does not present the medication as a quick fix without complications. Instead, it shows a more mixed picture: meaningful weight loss, improved activity, unexpected changes and plenty of questions about how the body responds.

In typical Clarkson fashion, even a medical update comes wrapped in jokes. But beneath the humour, his message is clear: Mounjaro has changed his health journey, and the effects have been more surprising than he expected.