Slimming pills bought online are “potentially dangerous” and can cause serious health problems, says the UK’s medicines watchdog. Side-effects can include heart problems, blurred vision and diarrhoea, and some contain banned ingredients. The Medicines and Healthcare products Regulatory Agency (MHRA) said people should go to their GP for advice first. A survey of 1,800 slimmers found one in three had bought pills online, with two-thirds experiencing side-effects. Most of those questioned by the MHRA and Slimming World had bought online because they had wanted to lose weight quickly. About 40% said they had not wanted to speak to a GP or pharmacist. Sarah-Jayne Walker, 30, saw diet pills as “a quick fix”, but they gave her palpitations and made her feel faint. She bought the pills online and took them for four months, before realising she had no idea what was in them. “The pills came in a little white bottle with no leaflet and no instructions,” she says. “Looking back, I think, ‘What was I doing?’ “I was in a desperate place – my weight had fluctuated for years – and I fell for the promises online.” Sarah-Jayne suffered from light-headedness, sickness and irritable bowel syndrome. “I knew the pills were affecting my body and I had become dependent on them,” she says. The MHRA said people should take medicines only after a consultation with their GP.