A look back at the most popular life extension articles of 2017.

The microbiome is emerging as a new player in human health. Researchers recently extended the lifespan of middle-aged animals by nearly 50% by infusing them with the poop of younger fish. [This article first appeared on the website LongevityFacts.com. Author: Brady Hartman. ]

Remember the young blood, old blood experiments in which the young blood of mice rejuvenated old mice?

Well, young poop may be even more rejuvenating.