Update 3/26/2019: In 2017, a small clinical trial that involved injecting plasma from young people into Alzheimer’s patients found extremely limited benefits. For more information on the young blood saga, check out our Verge Science video on the subject.

GDF11 is the typically unglamorous name of a protein that may hold the key to reversing — not merely delaying — the deleterious effects of aging. Back in 2005, scientists demonstrated that the blood of young mice helps older test subjects regenerate damaged muscle tissue, and now a paper from the Harvard Stem Cell Institute narrows the likely cause down to GDF11. The earlier experiments involved stitching together the circulatory systems of two mice — a process known as parabiosis — and showed signs of premature aging in the younger subjects alongside faster recovery in the older ones.

Amy Wagers, who contributed to the initial Stanford report, is now part of the Harvard research team behind the findings around GDF11. Mice treated with the isolated protein exhibited better cognition, endurance, and "improved function of every organ system studied so far." A separate study, led by Saul Villeda of the University of California in San Francisco, has concluded that simple transfusions of young blood plasma improve brain health and function in older mice.

There's been much excitement in the scientific community about these findings, though wariness remains about interpreting the causative link fully. Still, the Harvard team anticipates clinical trials of GDF11 therapy on humans could begin within the next three to five years, while Science reports that a company has already been set up to perform a small trial of plasma transfusions on Alzheimer's patients.