Can the blood of young people slow aging? Silicon Valley has bet billions it will

Researchers tested young blood plasma, the liquid part of blood, in mice and small human studies. In mice, it sometimes improved signs linked to aging, but mice do not directly predict what happens in humans. In people, small trials mainly tested whether young plasma was safe and found no reliable proof that it slowed aging or extended life. Some possible health improvements were reported, but the studies were too small and lacked strong comparison groups.

What this means for you: There is no good reason to buy young-plasma treatments or similar products for anti-aging. The evidence is weak, and these treatments can have real medical risks.