Character.AI, an app popular with children, is hosting chatbots that promote disordered eating.

The app is free, comes with no parental controls and has roughly 20 million active users. They can access a variety of chatbots modelled on different personas, from celebrities to teachers.

Reporters at Futurism found several of those chatbots were dedicated to "coaching" users in anorexia, with names like "4n4 coach" and "Ana" - online shorthand for the eating disorder.

One urged reporters to consume between 900 and 1,200 calories a day while exercising vigorously for 90 minutes - well below the USDA's dietary guidelines for teenagers. Another encouraged them to eat just one meal a day.

The chatbots reportedly had conversations with tens of thousands of users without being reviewed or taken down. The company later said it's refining safety practices and will delete chatbots that violate its terms of service.

It's the latest in a series of reports that have found Character's safeguarding lacking; a recent lawsuit alleges that another of the company's chatbots contributed to a 14-year-old boy's death by suicide earlier this year.