THERE’S no doubt that 2025 was officially the year of the ‘fat jab’ with more than 2.5 million Brits estimated to be using them.
While some celebs have been tight-lipped about their dramatic weight loss, others have confessed to using Ozempic, Mounjaro and Wegovy – and openly discussed the shock effects it has had on their shrinking bodies.
While many have hailed the treatment as “life-changing”, others have reported devastating side effects, from non-stop sickness to gallbladder concerns.
Here, we chart the most shocking celebrity fat jab transformations of the year.
Gemma Collins: “It’s been effortless”
After a decade of being reality TV’s poster girl for curvy women, Gemma Collins exclusively told The Sun that weight loss jabs had transformed her life.
The TOWIE icon, who had previously released a plus-sized clothing range, revealed she had been fighting a sad battle with her body for years.
At her heaviest – weighing over 23 stone and a dress size 26 – Gemma says couldn’t roll over in bed and was left unable to wear sexy lingerie.
So, after years of fad diets, in 2025, Gemma, 44, resorted to NHS-approved Mounjaro injections and dropped a total of three and a half stone and slimmed to a size 22.
At the time, she told The Sun: “I can’t believe I’ve finally found something that works. It’s been completely effortless – I don’t even want to eat anymore!
“I got on the scales and lost something like six kilograms in my first week…It’s been effortless.”
However, back in November, the former TOWIE star claimed she had to temporarily stop taking the injections after she was left in “excruciating” pain back in August.
Gemma explained that she “fell to the floor” while celebrating fiancé Rami Hawash’s birthday at a race track.
She told the Mirror: “I had to stop the jabs for a bit because I had a gallbladder attack in August, but they’ve assured me that it’s not actually linked to Mounjaro.”
According to the Oxford Online Pharmacy, gallbladder issues are one of the rare side effects of Mounjaro, which can occur in fewer than 1 in 100 people.
Despite the incident, it hadn’t completely deterred Gemma from using the medication.
The ITV star continued: “I’ve given it a rest and I’ve really been managing what I’ve been eating.”
Amy Tapper: “It’s changed my life”
Another celeb who opened up on her Mounjaro use in 2025 was Gogglebox‘s Amy Tapper.
Back in August, after years of fad diets, the TV favourite confirmed that she lost a seven stone thanks to Mounjaro.
The 25-year-old TV star, who won the nation’s hearts alongside her family on the Channel 4 sofa hit, dropped from a size 26 to a size 18 in just 12 months.
In an exclusive photoshoot with Fabulous, Amy showed off her incredible new look and opened up about her journey, as she said: “I’ve gone to doctors all my life and they can never tell me the problem – because there’s actually nothing wrong with me.
“My bloods are always amazing, I haven’t got polycystic ovaries, I haven’t got a thyroid problem and I haven’t got anything that usually makes you put on weight. It is just genetics.”
For single Amy, who starred on E4 matchmaking show Celebs Go Dating in 2018, trying to slim down had been a lifelong battle.
She added: “I have done every single diet under the sun. The same thing happens over and over again. I get three stone lighter and I don’t lose any more. Trying to lose weight became my full-time job.”
I want people to know that this has been my only option to get this far
Amy Tapper
As a result, Amy opened up on finally reaching breaking point and turning to the jabs, as she continued: “I felt there was nothing else I could do.
“I actually went to a doctor about surgery, because it got past the point of caring about how I look.”
After starting Mounjaro, Amy recognised: “I’m fitting into size 18 clothes for the first time since I was 15 or 16 – it’s hard for me to believe.
“It’s changed my life. I went to the theatre the other night and when I sat down, my thighs weren’t touching the person next to me, or the sides of the chairs. I had room.”
Amy acknowledged that the drugs had been “life-changing,” but found it frustrating when people call Mounjaro users “lazy.”
She added: “I also get annoyed that some people call it the ‘lazy way out’.
“I don’t want people to think that I’ve sat around for the last 17 years of my life not trying to lose weight.
“I want people to know that this has been my only option to get this far.”
Rebel Wilson: “My relationship with food is complicated”
After much speculation, actress Rebel Wilson first admitted in April 2024 that she had used Ozempic to shed a whopping 5 stone 7 lbs back in 2021.
But the star continued to keep the weight off and in 2025, left fans gobsmacked as she graced numerous star-studded events showing off her slender frame.
The 45-year-old told The Sunday Times: “Someone like me could have a bottomless appetite for sweets, so I think those drugs can be good.
“I feel strongly that young women shouldn’t try to obsess over looking like Victoria’s Secret models – they should just look like themselves.
“I know that my relationship with food is complicated.”
Rebel previously claimed to have successfully reached her 11 stone 7 lbs goal weight through high-intensity interval workouts and long hikes, complemented by a high-protein, low-sugar diet.
The Australian actress, who suffers from polycystic ovarian syndrome, a condition which affects fertility, originally decided to slim down following advice from her IVF doctor in 2019.
But due to her trope of playing “fat funny characters” in Hollywood films, she felt her weight loss wasn’t welcomed by her industry peers.
She said: “Basically no one apart from my mum wanted me to lose weight.
“People thought I’d lose my pigeonhole in my career – playing the fat funny character – and they wanted me to continue in that.”
Amy Schumer: “Just be real with the people”
In 2023, actress Amy Schumer confirmed that she had tried Ozempic “about a year ago” but stopped shortly after due to the side effects.
During an episode of Watch What Happens Live with Andy Cohen, Amy said: “I was one of the people that felt sick, I couldn’t play with my son.”
Despite seeing results, the American stand-up comedian said it wasn’t worth it.
“You’re like, ‘OK, this isn’t livable for me,’ but I immediately invested because I’m like, ‘Everyone and their mom is going to try it,’” she added.
After opening up on using fat jabs, the comedian encouraged other celebrities to be more honest if they are using Ozempic or similar medications.
She snapped: “Everybody (is) lying, everyone’s like, ‘Oh, smaller portions,’ like shut the f**k up, you’re on Ozempic or one of those things. Just be real with the people.”
As well as this, whilst starring on The Howard Stern Show, said: “I was vomiting. I was shriveling.”
But after battling with Ozempic, in 2025, Amy opened up on turning to Mounjaro, as she beamed: “Mounjaro’s been great… I’m having a really good experience with it and I wanted to keep it real with you about that.”
The blonde, who has lost a total of 3 stone 5 lbs thanks to weight loss injections, continued to flaunt her impressive weight loss and in October, looked smaller than ever as she flaunted her epic weight loss at a Paul McCartney gig with two pals in Las Vegas.
Then, in December, she stunned fans with a series of Instagram snaps, leaving fans gobsmacked with her youthful and slender appearance.
Meghan Trainor: “I feel great”
Meghan Trainor’s jaw-dropping transformation has become one of Hollywood’s biggest talking points and back in April, the All About That Bass singer finally owned up to the secret behind it.
The Grammy winner openly acknowledged that she doesn’t look the same as she did “10 years ago,” and admitted to being part of the Mounjaro trend.
After much speculation, the 32-year-old shared a post to her 18.3 million Instagram followers where she spoke about her journey towards becoming the “healthiest version of herself” for her children.
She wrote: “I’ve worked with a dietician, made huge lifestyle changes, started exercising with a trainer, and yes, I used science and support (shoutout to Mounjaro!) to help me after my 2nd pregnancy.
“And I’m so glad I did because I feel great.”
Everything you need to know about fat jabs
Weight loss jabs are all the rage as studies and patient stories reveal they help people shed flab at almost unbelievable rates, as well as appearing to reduce the risk of serious diseases.
Wegovy – a modified version of type 2 diabetes drug Ozempic – and Mounjaro are the leading weight loss injections used in the UK.
Wegovy, real name semaglutide, has been used on the NHS for years while Mounjaro (tirzepatide) is a newer and more powerful addition to the market.
Mounjaro accounts for most private prescriptions for weight loss.
How do they work?
The jabs work by suppressing your appetite, making you eat less so your body burns fat for energy instead and you lose weight.
They do this my mimicking a hormone called GLP-1, which signals to the brain when the stomach is full, so the drugs are officially called GLP-1 receptor agonists.
They slow down digestion and increase insulin production, lowering blood sugar, which is why they were first developed to treat type 2 diabetes in which patients’ sugar levels are too high.
Can I get them?
NHS prescriptions of Wegovy is controlled through specialist weight loss clinics, while Mounjaro is available from GPs but only for the highest risk patients.
For Wegovy, a patient will typically have to have a body mass index (BMI) of 30 or higher, classifying them as medically obese, and also have a weight-related health condition such as high blood pressure. They will be expected to have tried diet and exercise already.
Mounjaro is available from NHS GPs for weight loss but only to a tiny group of patients, with the rollout starting with those with a BMI higher than 40 and with four weight-related health conditions.
Private prescribers offer the jabs, most commonly Mounjaro, to anyone who is obese (BMI of 30+) or overweight (BMI 25-30) with a weight-related health risk.
Private pharmacies have been rapped for handing them out too easily and video calls or face-to-face appointments are now mandatory to check a patient is being truthful about their size and health.
Are there any risks?
Yes – side effects are common but most are relatively mild.
Around half of people taking the drug experience gut issues, including sickness, bloating, acid reflux, constipation and diarrhoea.
Dr Sarah Jarvis, GP and clinical consultant at patient.info, said: “One of the more uncommon side effects is severe acute pancreatitis, which is extremely painful and happens to one in 500 people.”
Other uncommon side effects include altered taste, kidney problems, allergic reactions, gallbladder problems and hypoglycemia.
Evidence has so far been inconclusive about whether the injections are damaging to patients’ mental health.
Just months later, the singer, who is a coach on The Voice, looked slimmer than ever as she flaunted her slender new frame on the red carpet at The Paper premier.
Meghan, who has lost over four stone in total, confessed that she had been using Mounjaro for weight loss alongside her husband, Spy Kids actor Daryl Sabara.
Speaking on the Workin’ On It podcast, the Made You Look singer said she decided to start Mounjaro after talking to her doctor and doing research, which saw her determine that it “had less side effects” than other weight loss drugs.
Since then, fans were stunned by her new look, as one said, “Didn’t even recognise her, she’s all treble now,” and another added, “Omg that doesn’t look like her at all what.”
Oprah Winfrey: “I thought thin people just had more willpower”
American telly personality Oprah Winfrey was one of the first celebrities to openly admit to using skinny jabs back in 2023.
The 71-year-old said ‘food noise’ – a term used to refer to the constant, intrusive thoughts about eating – caused her to never stop eating until she was full.
She said on her podcast: “One of the things that I realised the very first time I took a GLP-1 was that all these years, I thought that thin people just had more willpower.
“They ate better foods, they were able to stick to it longer, they never had a potato chip.
“And then I realised the very first time I took the GLP-1 that, ‘oh, they’re not even thinking about it’.
“They’re only eating when they’re hungry, and they’re stopping when they’re full.”
In 2025, the star, who is now said to be a size 10, continued showing off her dramatic Ozempic transformation, which saw her lose three stone in total.
She has since referred to weight loss injections as a “maintenance tool” rather than a quick solution.
After losing weight, Oprah stepped down from her role as a WeightWatchers ambassador and said it was due to her desire to “be able to talk about whatever I want to talk about” regarding weight-loss issues.
Serena Williams: “I’m discovering me again”
Tennis legend Serena Williams is another celebrity who totally transformed her appearance in 2025.
The sporting icon, 44, recently displayed the results of her 31lbs weight loss while posing for the cover of PORTER.
The seven-time Wimbledon champion oozed confidence as she showed off her incredible figure, flashing her toned legs and enviable arms.
In August, the mother revealed that she had lost over two stone with the aid of weight-loss jabs.
After trying to lose her baby weight naturally, Serena turned to healthcare company Ro, who guided her in choosing a GLP-1 treatment – which includes the likes of Ozempic and Mounjaro.
But Serena admitted she was initially hesitant, as she told People Magazine at the time: “I did a lot of research on it.
“I was like, ‘is this a shortcut? What are the benefits? What are not the benefits?’
“I really wanted to dive into it before I just did it.”
Discussing how her body has changed, mum-of-two Serena told Porter: “It was hard because when I was playing in the beginning – the first 15 years – my body was different. I had big boobs, I had a big butt.
“Every athlete was like super flat, super thin and beautiful, but in a different way. And I didn’t understand as an athlete how to deal with that.
“It does affect you mentally. Absolutely. You think you’re large for your whole life and you look [back] and you’re like, I was fit.
I want to leave behind anxiety, doubt and second-guessing myself
Serena Williams
“Yeah, I had big muscles. I didn’t look like these other girls but not everyone looks the same.”
Reflecting on her growth in body confidence, she beamed: “[Now] I’m not going to let anyone bring me down, I put enough stress on myself. The last thing I’m going to allow is someone else to do that.
“But I’m so happy that girls nowadays don’t have to go through it as much. I mean, I think internet trolls are different. So, you have that to deal with…
“I want to leave behind anxiety, doubt and second-guessing myself.
“I want to bring in more clarity, confidence that I made the right decisions and that you don’t always have to live only for your children. I’m discovering me again.”
Stephen Fry: “I was throwing up four, five times a day”
While many of our favourite female celebrities have admitted to using the jabs, Stephen Fry is another famous face who totally transformed their appearance thanks to the injections.
The actor, who appeared as a Faithful on the BBC’s The Celebrity Traitors, admitted to losing five and a half stone in just four months on Ozempic.
But despite transforming his appearance, the presenter revealed it left him vomiting multiple times a day.
The 66-year-old was initially amazed by the results of the injections, but soon had to stop taking them, as they left him feeling unwell and being violently sick.
Speaking to the Mirror, he recalled thinking: “I can’t do this.”
He then added: “I’d read about it, and I asked my doctor in America, and he said, ‘I think I can get you some’.
“He tried me on it, and the first week or so, I was thinking, ‘This is astonishing. Not only do I not want to eat, I don’t want any alcohol of any kind. This is going to be brilliant’.”
But the actor’s euphoria was short-lived, as he began experiencing grim side effects.
He continued: “I started feeling sick, and I started getting sicker and sicker and sicker.
“I was literally throwing up four, five times a day and I thought, ‘I can’t do this’. So that’s it.”
James Corden: “All it does is make you feel not hungry”
As well as Stephen, ahead of Gavin and Stacey’s iconic return, James Corden, 47, admitted to using Ozempic in an effort to slim down.
The actor previously confessed to being bullied over his weight and also experienced a food addiction, which saw him binge eat giant chocolate bars in his car.
As a result, James, who once topped the scales at 21 stone but has since shed six stone, turned to fat jabs.
However, the star attributes his success to intermittent fasting, boxing workouts and mindful eating.
James said: “I tried Ozempic, and it won’t be surprising to you when you look at me now, that it didn’t really work.
“I tried it for a bit and then what I realised was I was like, ‘Oh no, nothing about my eating has anything to do with being hungry.’
“All it does is make you feel not hungry. But I am very rarely eating [just because I’m hungry].”
He added: “You are looking at someone who’s eaten a king size, and when I say king size Dairy Milk – one you give someone for Christmas – in a carwash.
“None of that was like, oh, I’m so hungry. It is not that, it’s something else.”
When discussing how he’d really lost the weight, as reported by the Daily Record, the Smithy star revealed that he waits until noon to eat and starts most days with a boxing session and sometimes just an apple or a 15 calorie sugar-free vitamin drink for breakfast.
He also told The Sun: “I have a trainer who I box with most mornings, and so far today I’ve had an apple. I try to eat healthily and not deprive myself.”
