Injections of semaglutide, the drug behind the jabs Ozempic and Wegovy, have taken the world by storm.

The 'game changing' weekly injections have helped thousands of people who need to lose weight and improve their health.

But they have also been dubbed Hollywood's 'worst kept slimming secret' with multiple celebs reportedly using the drugs in secret to keep trim.

And an increasing number of regular Brits also seem to be taking the drug secretly as a 'quick-fix' to become 'beach-body ready', having obtaining it from online pharmacies under false pretences. 

Here, experts reveal some the ways to spot if somebody might be taking semaglutide on the side, and what people can do to counteract the effects.

They might lose their curves... 

The flab-busting drugs doesn't discriminate which fat it targets. 

That's because the drugs mimic GLP-1, a hormone made naturally in the body that helps slow the passage of food through the stomach — which makes people feel less hungry.

This alters the brain’s appetite regulation, so that people feel satiated despite eating less and they also don’t experience cravings for treat foods. 

As a result, people don't eat as much and lose weight —but not just belly fat. 

You may notice someone who is taking the drug start to develop thinner arms and legs and an overall less curvy physique. 

Some of the unflattering side-effects reported by women include their breasts shrinking and their behinds becoming flatter. 

'It can change appearance and for some people that may not be welcome,' warns Professor Alex Mira, consultant endocrinologist at Ulster University. 

He told MailOnline this wasn't a side-effect specific to semaglutide and similar effects were seen from other types of calorie-restrictive weight-loss such as gastric bypass surgery. 

'The appearance changes, such as what people call Ozempic face, Ozempic bottom, is not just an Ozmepic effect, that can happen with any form of weight loss,' he said.

'It doesn't matter what has caused it, but the weight loss changes the facial appearance because you lose predominantly fat, the same thing happens to the butt and it happens throughout the body.'

Users of the slimming jab have also themselves warned about the unwelcome consequence — 'Ozempic butt'. 

The backside is one of the main areas where subcutaneous fat — fat directly beneath the skin — accumulates, and as a result, is some of the first to go during weight loss. 

It also contains a group of three large muscles, called the glutes, which may also shrink if someone takes the drug without exercising and eating a high-protein diet. 

In one video posted to TikTok under the #ozempicbutt, social media user @jocelyngarcia3514 shared a full body video of her loose skin around her bum. 

'What does an ozempic/semaglutide butt look like?,' she wrote.

'You guessed it? Loose skin and cellulite (nothing to brag about, results vary).'

Similarly, users of the drug have also reported their breasts reducing in size at the same time their waistline shrinks.   

TV personality, Sharon Osbourne, 71, previously confessed she lost 'too much' weight on Ozempic.

She told Daily Mail in January that she lost 'almost half' her body weight.

'The result was that I had flesh hanging everywhere. My breasts were flat and sagging,' she said.

The music manager, who has three children with rock star husband Ozzy, 74, had to undergo a string of cosmetic procedures to rectify the unwanted side effects of her weight loss. 

It can't be denied however, that losing excess flab from certain areas will boost your overall health, as Professor Mira explains. 

'Fat loss also happens on the abdomen which is really important from a metabolic perspective, not just from an appearance perspective,' he said. 

'It is good for the prevention of development of diabetes, high blood pressure and heart disease.

However, it is not just fat that people lose while taking semaglutide.

That's because the weight-loss injections don't target fat specifically, instead, triggering weight loss by affecting appetite.

As a consequence, this means patients can also lose muscle mass by not eating as much protein, the building block of muscle, as before taking the drug.

Muscle loss can make you look less toned and change the shape of the arms and legs as well as the glutes, which is the biggest muscle group in the body.

They may have the gaunt look of Ozempic face...

Semaglutide can also remove fat from the face making many people look gaunt, colloquially known as 'Ozempic face'.

This tell-tale sign can make people have sunken eyes, gaunt cheeks and saggy skin.

Since the fat in our face helps gives smooth plump cheeks and wrinkle free foreheads, rapidly losing it can also make people rapidly look much older.

Nutritionist Rose Ferguson told the Times more of her celebrity clients have been 'freaking out' about developing so-called 'Ozempic face' from weight loss drugs.

The 49-year-old former model, who is close friends with Kate Moss, says a surge of people have come to her concerned about their face transforming from drugs like Ozempic and Wegovy.

Celebrities who have developed 'Ozempic face', either because they have taken such drugs or due to other weight loss methods, include Robbie Williams, Scott Disick and Sharon Osbourne. 

Dr Smita Ramanadham, a plastic surgeon in New Jersey, recently told DailyMail.com: 'Ozempic face is essentially the same characteristics that we see when patients have rapid or regular weight loss.

'We see a loss of volume in the face, and when we lose fat in the face we see signs like the cheeks are more sunken in, more sagging skin and a general hollowing out of the features.

'Sometimes, it can have the effect of actually making a person look older — because the fat in our cheeks is what gives us a more youthful look.' 

Pointing to the example of singer Robbie Williams, Dr Ramanadham said: 'You can see a hollowing under the eyes and the cheeks and more wrinkles appearing because of a loss of volume. With Robbie, you can see the direct results of weight loss.'

So, can you counteract Ozempic butt/face/arms?

Muscle loss is often seen as an unwanted side-effect of taking semaglutide drugs, but experts are undecided on whether this is detrimental, or in fact beneficial, to long term health.

'One school of thought is that any form of muscle loss is bad,' Professor Mira said. 

He added: 'That's because muscle is a metabolically active organ and it burns energy. So, the less muscle you have the less your energy expenditure, and that's not good for weight loss or for the absorption of sugar from the blood. 

'So, it is bad in terms of the development of diabetes and it's not good from a metabolic perspective.'

Another theory is if you have less fat and less weight, you need less muscle to carry that person and that's why you lose muscle, Professor Mira explains. 

Other experts say we lose muscle because if someone is obese their muscle will also contain some fat. 

So, therefore when fat is removed in the process of weight loss, the muscle volume also reduces. 

But experts say this could be healthier muscle overall because it doesn't have that fat, Professor Mira explains. 

Although there is not yet enough data to confirm which theory is correct, muscle loss is not only concerning from an aesthetic perspective, as its absence can also increase your risk of falls and fractures and make you feel weaker. 

'The only way to protect your muscles is to increase your protein intake,' Professor Mira warns. 

Protein, which is found naturally in meat, fish, eggs and beans, is used by the body to build and maintain muscle. 

Earlier this year healthcare product company, Abbott, released a protein shake in the US, which contains 30 grams of protein — about half the daily amount that the NHS recommends— specifically for people taking weight-loss drugs

Studies show that a high-protein diet can help increase muscle mass and, according to Abbott, patients need to take in 50 per cent more during a weight loss regime to maintain a healthy body. 

Food giant Nestle has also taken to the semaglutide market, launching a range of collagen and protein powders to counteract the side effects of weight loss drugs after a slump in snack sales. 

These new weight-loss friendly products include a supplement for hair growth, electrolyte tablets with strawberry-lemonade flavour, plus collagen peptides to boost skin elasticity. 

But soon protein shakes might not be the only answer to warding off problems like 'Ozempic butt'.

Professor Mira said pharmaceutical companies are currently developing medications, specifically to counteract the muscle loss patients experience, according to Professor Mira.

'In the future, we are likely to have medications that do counteract the effects of weight loss on muscle,' he said.