Despite the considerable efforts made by scientists and doctors to determine a single, unified theory of aging, there is still no strong consensus within the longevity community as to its actual root cause. The various aging theories that have been developed over the past century have largely failed to explain aging on their own, but they have shed some good light on the aging process, and our understanding of it.

In my recent book, The Science and technology of Growing Young, I cover two theories of aging: the free radical theory, and telomeres. I also gave a short mention to Dr. David Sinclair's "loss of epigenetic information" approach and Dr. Aubrey de Grey's "accumulation of molecular damage."

However, there are more theories that you can read about below:

  1. American Federation for Aging Research   
  2. Lumen Learning 
  3. Physiopedia  
  4. Verywell Health