Osaka police referred three people to prosecutors last week for allegedly selling the diabetes drug Mounjaro online without authorization, sparking widespread debate over the misuse of weight-loss drugs in Japan.

The incident highlighted just how high demand is for the drug, where some women seeking it are already medically underweight or close to that level.

Health minister Kenichiro Ueno warned Friday at a news conference that the illegal consumer-to-consumer trading of Mounjaro is on the rise and said the ministry is stepping up surveillance on social media.