Hi Casper,
it is not just blood that heals, as blood is an information carrier - so, I would take in consideration the whole young organism's energy, its lesser toxicity, lesser wear-and-tear, etc.
I have an acquaintance with an internal bleeding disorder who've received a lot of blood, but it didn't helped her much, actually confused her organism with too much "contradictory information".
_https://www.kidneyresearchuk.org/health-information/anaemia-and-kidney-disease
This article says that anemia is a disease of kidneys. Well, in Chinese medicine the kidneys hold the yuan qi, the ancestral energy received at birth. The better you take care of it, the fitter you are. This is also the sexual energy which give life at its turn.
FWIW
Joy