Exosomes are tiny balls of fat that allow cells to communicate with each other in our bodies. They're being actively researched as an experimental new type of medicine, and they're also being used in the cosmetics industry in serums, as well as being injected into people's skin. Researchers have raised concerns about the safety of this hot new trend in beauty.

Presenter James Gallagher meets Dr James Edgar from the University of Cambridge who studies exosomes in his lab, he's also joined by consultant Kamal Kaur who advises the cosmetics industry on regulation around products containing exosomes, and we head to one of the UK's hot spots for beauty clinics and dermatology - the Marlyebone area of London - to meet consultant dermatologist in the NHS and One Wellbeck, Dr Ellie Rashid.

Also in the programme, a new physio app is being trialled by the NHS. It's been rolled out to patients in Lothian in Scotland and we meet the people who have been using it, the real-life physio behind it and hear whether apps could be the way many people access physio in the future.

Producer: Tom Bonnett with Debbie Kilbride Assistant Producer: Minnie Harrop Editor: Ilan Goodman