A company in Monterey, California, is out for blood. Young blood, specifically. Jesse Karmazin, 31, and his startup, Ambrosia, are looking for volunteers to be part of a clinical trial that hopes to slow down ageing. How? By injecting participants aged 35 and older with the blood plasma of people aged 16-25 for a vampire-inspired fountain of youth. Karmazin has a medical degree, but he's not licensed to practise. Instead, he's banking on experience earned from his time at Stanford and as an intern at the US National Institute on Aging. He was inspired by a study from 2014, in which older rats were injected with plasma from younger ones. After the transfusion, researchers found that the elderly rats were more able to learn and had an improved memory. "Some patients got young blood and others got older blood, and I was able to do some statistics on it, and the results looked really awesome," Karmazin told Business Insider. "And I thought, this is the kind of therapy that I'd want to be available to me." Karmazin is looking for volunteers to participate, though they'll have to fork out around £6,600 to be a part of the preliminary study. Once their cheques have cleared, they'll be part of a two-day study that will pump 1.5 litres of donor plasma into their veins and record any improvement. Karmazin told The Next Web that he's witnessed the procedure and its benefits dozens of times. He also told the site that he'd already performed the procedure on 30 people and they're already reaping the benefits, such as "renewed focus and improved appearance and muscle tone." Not everyone is convinced, however. For starters, a sample size of 30 is too small to be significant and Karmazin's work doesn't take into account the placebo effect. Plus, claims like "renewed focus" can't be objectively measured. "There’s just no clinical evidence [that the treatment will be beneficial], and you’re basically abusing people’s trust and the public excitement around this,” neuroscientist Tony Wyss-Coray, PhD, of Stanford University in Palo Alto, CA, told Science. He performed the 2014 rat study. Instead of seeking to turn back the hands of time, however, Wyss-Coray is using the findings from his study to see if it can be beneficial to Alzheimer's patients. The results of his continued work have not yet been published. If you're interested and have £6,600 to spare (a small price for eternal youth), you can join the likes of PayPal's Peter Thiel, who just expressed interest in Ambrosia and makes no secret of his desire to live forever.