Molecule, a pill promising rapid weight loss, went viral on Russian TikTok earlier this year.
Young people's feeds started filling up with captions like Take Molecule and forget food exists, and Do you want to sit in the back of the class in oversized clothes?.
Clips showed fridges lined with blue boxes featuring holograms and Molecule Plus labels.
The orders began piling in, as teenagers shared their weight-loss journeys on social media.
But there was a catch.
Maria, 22, had purchased the pill from a popular online retailer. She took two pills per day and, after two weeks, says her mouth dried up and she completely lost her appetite.
I had absolutely no desire to eat, let alone drink. I was nervous. I was constantly biting my lips and chewing my cheeks, she recounts.
Maria developed severe anxiety and began having negative thoughts. These pills were having a profound effect on my psyche, she says.
Maria, who lives in St Petersburg, says she wasn't prepared for such severe side effects.
Other TikTok users mentioned dilated pupils, tremors, and insomnia. At least three schoolchildren are reported to have ended up in hospital.
In April, a schoolgirl in Chita, Siberia, needed hospital care after overdosing on Molecule. Her mother stated that her daughter had been admitted to intensive care after taking several pills at once.
And in May, a 13-year-old boy from St Petersburg needed hospital care after experiencing hallucinations and panic attacks. He had reportedly asked a friend to buy him the pill because he was being teased at school about his weight.
The packaging for Molecule pills often lists natural ingredients such as dandelion root and fennel seed extract.
However, investigative journalists found they contained a banned substance called sibutramine, previously used as an appetite suppressant associated with increased risks of heart attacks and strokes.
The unlicensed pills cost about £6-7 ($8-9) for a 20-day supply, considerably cheaper than recognized weight-loss injections that cost up to £160 per month.
Experts caution against self-administration, citing overdose risks and unhealthy consequences, particularly for young individuals with existing eating disorders.
Maria, who suffered serious side effects, now discourages others from taking the pills, cautioning: You will regret it tenfold. Despite her warnings, Molecule remains popular online, symbolizing a growing health risk among Russian youth.