Young blood is blood from a young organism. Studies have shown regenerative effects in old mice whose blood was exchanged with young blood. However, research suggests this is was due to circulatory access to the young donors' organs and dilution of old blood, rather than rejuvenation by the young blood. Controversial young blood transfusion trials with humans have had unclear results.
Multiple studies have shown positive effects in old mice who have undergone parabiosis, the connection of circulatory systems, with young mice. However, young mice with blood from old mice see negative effects more prominent than benefits to old mice with young blood.
Some lesser benefit, such as muscle regeneration, has also been seen in old mice who have undergone non-parabiotic blood exchange with young mice. Researchers suggested that the parabiosis might have been more effective due to access to the young mice's organs.
A more recent study has shown that diluting old blood plasma with saline was at least as rejuvenating as non-parabiotic blood exchange. The researchers suggest that this is due to simply removing harmful factors in old blood, thus giving an explanation of the benefits in the non-parabiotic exchange other than rejuvenating factors in young blood.
Biotech startup Ambrosia ran a human trial from 2016 to 2018. This was criticised for its risk to participants, requirement for participants to pay thousands of dollars, lack of a control group, and lack of published result data despite the declared intention to publish them. Additionally, a 65-year-old participant died the month after the conclusion of the study, which was initially denied but later admitted by Ambrosia's founder.
Another trial was started in 2018 by the Maharaj Institute with estimated completion in 2023. Its plan is to give monthly transfusions of blood plasma from young donors to old and frail participants. The trial also has no placebo group and asked for payment to participate.
- Rebo, J; Mehdipour, M; Gathwala, R; et al (22 November 2016). "A single heterochronic blood exchange reveals rapid inhibition of multiple tissues by old blood". Nature Communications. 7 (13363). doi:10.1038/ncomms13363
- Mehdipour, M; Skinner, C; Wong, N; Lieb, M; Liu, C; Etienne, J; Kato, C; Kiprov, D; Conboy, M J; Conboy, I M (30 May 2020). "Rejuvenation of three germ layers tissues by exchanging old blood plasma with saline-albumin". Aging. 12 (10). doi:10.18632/aging.103418
- "Young Donor Plasma Transfusion and Age-Related Biomarkers". ClinicalTrials.gov.
- Liebelson, Dana; Cook, Jesselyn (29 December 2018). "He Hawks Young Blood As A New Miracle Treatment. All That's Missing Is Proof." HuffPost.
- Cook, Jesselyn (3 October 2019). "Notorious ‘Young Blood’ Doctor Claims Dead Patient Faked His Own Death". HuffPost.
- "Safety, Efficacy of FFP From Healthy Donors to AmeliorateFrailty and Enhance Immune Function in Older Individuals". ClinicalTrials.gov.
- Robbins, Rebecca (2 March 2018). "Young-Blood Transfusions Are on the Menu at Society Gala". STAT.
- Basu, Tanya; Weill, Kelly (22 February 2019). "FDA Warns: Don't Give These Companies Your 'Young Blood'". The Daily Beast.