File on 4 Investigates whether the risks associated with the popular hair loss drug Finasteride are understood, after a 2024 review by UK drug safety regulator the MHRA prompted by a lack of awareness of the drug’s side-effects. Finasteride’s most common side effects are reduced libido and erectile dysfunction, affecting more than one in a hundred patients. Some people also report low mood and suicidal thoughts.

As Johnny I'Anson discovers some hair loss clinics are failing to adequately warn customers at the consultation stage of the sexual side effects assocated with Finasteride.

The drug, which is highly effective at halting hair loss, is only available by private prescription for hair loss purposes.

But File on 4 Investigates discovers influencer accounts on the social media site TikTok promoting finasteride, also offering discounts for Finasteride with Manual, a popular UK men's health company. A lawyer expert told us that the videos we found constituted advertising.

As a prescription-only medicine, it’s illegal to advertise finasteride to the public like this. This programme flagged the videos to TikTok, and they have since been removed. The company has also banned three of the accounts promoting the drug, saying they breached its rules. Manual said it was not involved in the making of the influencers’ videos.

Presenter: Johnny I'Anson

Details of organisations offering help and support with mental health are available at bbc.co.uk/actionline