A “game changer” weight loss drug, said to be Hollywood's "worst kept secret" will soon be made available through the NHS in England for certain people living with obesity, health officials have announced.

Wegovy, or semaglutide, is usually prescribed as a type 2 diabetes medication that blunts appetite.

It has the same ingredient as Ozempic, which has been causing a stir recently having said to be used by celebrities to manage their weight.

In February, it emerged that some high street chemists in England will prescribe the drug, if suitable, through their online doctor services, now thousands are expected to be offered the appetite suppressant Wegovy on prescription after the National Institute for Health and Care Excellence (NICE) gave it the green light for NHS use.

A previous study found that people who are given the drug, which comes as a weekly injection, saw their weight drop by 12% on average after 68 weeks.

NICE has issued final guidance recommending semaglutide (also known as Wegovy and made by Novo Nordisk) for adults with at least one weight-related condition and a body mass index (BMI) score of at least 35.

People will only be given Wegovy on prescription as part of a specialist weight management service involving input from several professionals, and for a maximum of two years.

But experts have warned that there are some potentially nasty side effects to using the drug as an aid to weight loss, with Dr Amir Khan recently appearing on both GMB and Lorraine to discuss the controversy and issue some advice.

From how the drug allegedly works to the health risks, here's everything you need to know about Wegovy or Ozempic in 11 points.

What is Ozempic? Ozempic, Ryblesus and Wegovy are all brand names for a compound called semaglutide. The drug is typically used as a diabetes medication, can be prescribed in various doses and can be in the form of a weekly injection – administered in the stomach, thigh or arm – or a daily oral tablet.

The drug reportedly reduces appetite. "It is a once weekly injection and a hormone that our guts naturally produce," explained Dr Amir Khan on ITV's Lorraine show during a discussion about the drug. "It sends messages up to the pancreas to start producing insulin. But one of the side effects is it slows down the movement of food in the gut so you stay fuller for longer and you don't have much of an appetite. That means you eat less which results in weight loss."

The drug is rumoured to be secretly used by many Hollywood stars. At the Critics Choice Awards earlier this year Chelsea Handler hinted that many celebrities were taking the injectable. "Like when celebrities joke they lost weight by drinking water, but really it's because everyone's on Ozempic," she joked. "Even my housekeeper's on Ozempic."

Searches on social media also link the Kardashians with the drug. But despite Kim Kardashian never confirming her use of Ozempic and her sister, Khloe, issuing a statement denying that she'd used it, it continues to clock up hashtags.

Other celebrities have openly admitted using the drug as a weight loss aid including Elon Musk, who told Twitter he'd tried it – alongside a similar drug, Wegovy. The Tesla founder said the once-weekly injectable was his secret weapon for being "down 30lbs". Jeremy Clarkson also recently discussed using the drug in a bid to lose weight and help prevent type 2 diabetes.

It's causing quite the buzz online. Thanks to its reputation as the weight loss drug du jour, Ozempic is quickly clocking up views and shares on social media. On TikTok the hashtag #ozempic already has 414.1 million views and counting, while Instagram is littered with users sharing their "Ozempic journey" to weight loss.

The drug was hailed a potential 'game changer' during an official UK study. It first started causing a buzz in the UK as a weight management tool after a University College London study, published in The New England Journal of Medicine, found just over a third (35%) of people who took it for obesity lost more than a fifth of their total body weight.

The drug continues to spark controversy. While the drug is going to be available via pharmacies as a prescribed obesity treatment, doctors have concerns about the risks of those using it not being carefully monitored by a medical professional.

It is also believed that the increase in interest surrounding the drug as a weight loss aid is thought to have caused a shortage for those needing the medication for diabetes.

Ozempic does come with risks. Dr Amir Khan warned that side effects of the medication could include "nausea, vomiting, feeling bloated, diarrhoea, but in some, more serious, cases it can cause inflammation of the pancreas, that's pancreatitis."

He added it can also cause gall bladder problems. "It can even cause kidney failure," he said, "so really it should only be available on prescription. I do prescribe it to my patients living with type 2 diabetes, but it's very carefully monitored. It is not just given online."

Eating disorder charities also have concerns. “Weight-loss medications like semaglutide can be extremely attractive to people with eating disorders as they appear to provide quick results," Tom Quinn, Beat’s director of external affairs, explains.

“However, these medications can be very dangerous as they can worsen harmful thoughts and behaviours for those unwell, or contribute to an eating disorder developing for someone who is already vulnerable.”

Doctors say weight loss medications aren't a magic cure. The NHS advises speaking to your GP for advice about losing weight safely "by eating a healthy, balanced diet and doing regular physical activity".

They can also let you know about other useful services, such as local weight loss groups (either provided by the NHS or your local council, as well as private clubs that you pay for) and 'exercise on prescription' (where you're referred to a local active health team for sessions with a qualified trainer).

Additional reporting PA.