Johnty Andersen, Researcher into Biotechnology, Nanotechnology and Anti-Aging Medicine and
David Pearce, co-founder with Nick Bostrom of the World Transhumanist Association (H+)
I don't take anything. I have the good fortune to be doing very well for my age as measured by very thorough tests (I was given Kronos's now-discontinued comprehensive screen three times in the past decade), so for me the best policy is "if it ain't broke don't fix it". People who have drawn short straws in the aging stakes should therefore not be guided by my choice in this.