BBC News | Of Mice and Old Men: Silicon Valley's quest to beat ageing - http://www.bbc.com/news/technology-42832015?ocid=wsnews.chat-apps.in-app-msg.whatsapp.trial.link1_.auin
To find out more, I drove to the Buck Institute for Research on Aging which is based in the beautiful city of Novato, near California's wine country. It's the kind of place that would make you want to live as long as possible.
Here I met Dr Eric Verdin, one of the world's foremost experts on the science of ageing.
"Fasting elicits a response in your body that triggers a protection against many of the diseases that are associated with ageing" he explained.
"So there's growing realisation that multiple forms of fasting might actually be beneficial in the long term. The science is really strong in this area."
He was less persuaded by Alkahest's claims of using young blood to rejuvenate the old.