As recently as a few years ago, the idea of a self-administered injection that would deliver proven weight-loss results might have sounded fantastical. Today, these medications are a reality and a global phenomenon; hailed in many quarters as “miracle drugs" for their success in treating obesity and diabetes.

They do this by replicating a gut hormone called GLP‑1, which tells the brain you’ve eaten enough and nudges the pancreas to release insulin; and this hormone was discovered and decoded thanks to years of work by today's guest.

Jens Juul Holst is a Professor of Medical Physiology and Biomedical Sciences at the University of Copenhagen. His efforts laid the groundwork for today’s weight loss jabs, earning him a slew of high-profile accolades and awards. Now it seems they might not only have positive impacts on obesity and diabetes, but also other health issues...

But alongside the big success comes some big questions: including concerns over side effects, weight regain post-treatment, the black market in such drugs, and their cost and accessibility.

In a frank conversation with Professor Jim Al-Khalili, Jens address these issues and shares his hopes for the future of GLP-1-focused research.

Presented by Jim Al-Khalili Produced by Lucy Taylor A BBC Studios production