The key to eternal youth is not in bizarre beauty treatments, cosmetic procedures, or facial creams; it may lie in young blood. Although this may sound like the gory stuff that you hear in gothic horror novels or vampire fandom, “vampire therapy” can reverse the effects of aging — in mice, and possibly humans. According to two separate teams of scientists from Harvard and Stanford universities, blood transfusions from young people may not only help older people fix their hearts, but they may keep the brain and muscles young and strong.

The experiments suggest new possible treatments for neurodegenerative diseases from Alzheimer’s to dementia, but scientists also hope they can find what is in the blood, so blood transfusions can be eliminated in the process. GDF11, a youth protein present in the bloodstream in large quantities when we’re young, is responsible for keeping the brain and muscles in our bodies young and strong. However, as we age, the youth protein peters out. Both teams started with very simple approaches in their experiments: They transfused blood from young mice into older mice.

In the Stanford study published in the journal Nature Medicine, Dr. Saul Villeda and his colleagues sought to investigate the effects injecting young blood has on mice's brains. Researchers repeatedly injected the blood of 3-month-old mice into 18-month-old mice near the end of their natural life span over the course of three weeks. The vampire therapy was found to help improve the performance of the elderly mice when it came to memory and learning tasks. Their brains also showed structural, molecular, and functional changes. However, blood infusions from other elderly mice had no effect on the aging mice.

“We’ve shown that at least some age-related impairments in brain function are reversible. They’re not final,” said Villeda, now a faculty fellow at the University of California, San Francisco, The Telegraph reported. Villeda and his research team saw evidence of the new connections that were forming in the hippocampus, the brain region essential to memory and sensitive to aging. They also noticed the dendritic spines, extensions from the branches of neurons thought to play a role in memory formation, became denser.

In the Harvard study published in the journal Science, Dr. Amy Wagers sought to examine whether the youth protein was responsible for the rejuvenation of other tissues in mice. Last year, Wagers and her team demonstrated the young blood of mice could rejuvenate the hearts of old mice. Now, the Harvard scientists found that GDF11 revived stem cells in old muscles in older mice, making them stronger and increasing their endurance. The rising levels of the protein in older mice improved the function of every organ in the body.

“We all wonder why we were stronger and mentally more agile when young, and these two unusually exciting papers actually point to a possible answer: the higher levels of the protein GDF11 we have when young,” said Dr. Doug Melton, who helps head the department at Harvard, NBC News reported. “There seems to be little question that, GDF11 has an amazing capacity to restore aging muscle and brain function.” These findings give doctors insight on possibly living a healthier future as the protein seems to reverse some of the decline of aging.

Now, the next step is to see how this can be applied to humans. These studies warrant future investigation in aged humans and those who suffer from age-related neurodegenerative disorders. The treatments used in these mice do show a level of rejuvenation in aspects related to learning and memory, but they’re of unknown significance to humans since the study didn’t observe the same type of cognitive decline in Alzheimer’s.

The key to being forever young may simply lie in vampire therapy, as levels of some proteins are more abundant in young blood and can awaken the stem cells, and cause the brain and muscles to be younger and stronger.

Source: Berdnik D, Bieri G, Castellano JM, et al. Young blood reverses age-related impairments in cognitive function and synaptic plasticity in mice. Nature Medicine. 2014.