This is actually one of the mechanisms behind "blood swaps" done by the rich and weird. Donating blood frequently also reduces various accumulated "factors" that reduce kidney stress, encourage healthy new blood, and is overall beneficial to health.

Various other mechanisms can improve how effective your body is at recycling cells, encouraging autophagy and filtering things in the blood. There are a whole suite of various supplements and medicines that work in this system.

As undead, though, vampires no longer produce new living blood, so require fresh blood of the living to restore lost function. Or something.

I guess that'd make Bryan Johnson the ultimate thrall?

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