A woman has described how she could not speak or stand before being rushed to hospital after taking an unlicensed weight-loss jab.
Kay Roscoe, 38, from Birkenhead, said she had used a substance sold as retatrutide, or "reta", for two months before falling seriously ill.
The experimental drug is not approved for general use and is available only through clinical trials. Products claiming to contain it are widely sold online, but it is not known whether Kay took genuine retatrutide.
She is now warning others about the risks. "I am the luckiest person to be alive. Honestly I can't say it enough, get off the pens," she said.
On the day of her collapse, Kay had been due to go out for a roast dinner with a friend.
When she failed to answer her phone, her friend went to check on her at home and found her unable to speak or stand.
"I was frothing at the mouth, not responsive at all," she said, recounting what her friend later told her. "My eyes were moving around, but I couldn't speak or move or do anything."
Kay, who has no memory of the episode, said her friends rang an ambulance and told paramedics she had been taking "reta" before she was rushed to hospital.
She said it took more than an hour for her to regain consciousness.
Hospital tests confirmed Kay had suffered severe hypoglycaemia, a condition where blood sugar falls to dangerously low levels.
Medical records attributed the episode to an unlicensed weight-loss injection.
Kay said doctors warned her she could have died if her friend had found her just half an hour later.
In the weeks since, Kay said she has continued to suffer health problems, including extreme fatigue.
She said further tests had shown she had signs of liver damage and high cholesterol, neither of which she had before the episode.
"I don't drink, I don't take drugs, I don't smoke," she said. "I've never had a problem with anything like this. I just feel run down and drained. My body feels all over the place."
Kay had started injecting herself with the substance about two months earlier.
A former regular gym-goer, she said she was attracted to the prospect of quicker weight loss after seeing posts on social media.
"Going to the gym takes longer. I saw my friends on it and saw them losing weight. And I thought, everyone is taking it and they've all been fine, so I'll try it. I didn't really read into the licensing," she said.
Kay bought the jab from a friend and said she believed it was legitimate after scanning a QR code on the pen, which took her to what appeared to be a pharmaceutical website.
Initially, she was pleased with the results, saying she lost a "drastic amount" of weight within weeks. But the injections had also significantly reduced her appetite.
"I was made up with the change, but I was never hungry," she said.
In the days leading up to her hospital admission, Kay said she had eaten very little.
Retatrutide is being developed by pharmaceutical company Eli Lilly as a potential treatment for obesity.
Unlike existing weight-loss drugs, such as Wegovy and Mounjaro, which target one or two hormone receptors, retatrutide acts on three, earning it the nickname "triple G".
The drug is still undergoing clinical trials, with Eli Lilly planning to apply for approval in the US early next year.
A previous BBC investigation found vials purporting to be "reta" were being sold in gyms, beauty salons, hairdressers, on social media and even by flower sellers.
Eli Lilly said retatrutide had not been approved by any regulator and could not legally be sold for human use.
A spokesperson said: "Counterfeit and black market medicines are unverified, unregulated and potentially dangerous - in some cases, deadly."
The company said it was working with the UK's medicines regulator, the MHRA, police and social media platforms to remove illegal products.
"Stronger, coordinated law enforcement must be sustained to protect UK patients from unsafe fake medicines," the spokesperson added.
Since sharing her story on Facebook, Kay said she had received messages from about 100 people describing their own experiences with weight-loss injections.
"You never think anything's going to happen to you. But we all do things because we want to lose weight," she said. "You see a new thing on the market and want to try it. I just think it's very dangerous."
Kay also revealed the impact her ordeal has had on her family.
"They've gone mad at me and warned me not to take it. They said, 'There's nothing of you', but you don't see yourself like that, do you?"
She now plans to return to the gym and eat healthily.
"Please, everyone, stop taking a needle to be skinny. Imagine not waking up, like I nearly didn't. And then my poor family losing someone over taking something you didn't even know what it was."
