It sounds like something out of a sci-fi movie, but it's real: Ambrosia, a startup from entrepreneur Jesse Karmazin, pays for the blood of people under the age of 25, then sells anyone over age 35 a transfusion of the younger blood for $8,000—the only US company to offer such a service, Vanity Fair reports. Why? It's thanks to a phenomenon known as parabiosis, in which two beings are sewn together, their veins conjoined. Researchers who did this to mice in a 2013 study found that certain aspects of aging were reversed in older mice who got blood from younger ones, but the results haven't been replicated by other researchers. There's also the fact that any similar benefits in humans are only hypothetical at this point, but that doesn't make the idea any less tantalizing to some, CNBC reports.
PayPal co-founder Peter Thiel, for example, told Inc. magazine last year he was "looking into parabiosis stuff." (Karmazin says Thiel isn't an Ambrosia client, and it's not clear whether Thiel has actually started getting transfusions.) Despite the fact that benefits of parabiosis in humans haven't yet been scientifically documented, Karmazin (who gets his company's supply of young blood from blood banks) claims some of Ambrosia's 100 or so clients have seen blood biomarkers for heart disease, cancer, and Alzheimer's disease lessen, and that at least two clients have seen their actual Alzheimer's symptoms decrease. "Whatever is in young blood is causing changes that appear to make the aging process reverse," he tells New Scientist. But due to lack of clinical evidence, some scientists find the idea controversial, and even Karmazin notes some of his clients have reported the effects eventually wear off. (DC cops nabbed a man who said he was collecting blood for research.)