Creating this from a comment I saw.
One fandom user commented on the Vitae page: So in essence they were just gathering "lactic acid", which is produced during great stress, even to the point of killing small animals like reptiles if the amount builds up in their bodies for too long. Interesting.
I replied:
It's not like lactic acid, it's more like the hormones produced by the adrenal gland during stress. Hormones secreted by the adrenal medulla are epinephrine and norepinepherine. Most people know epinephrine by its other name—adrenaline. Norepinepherine, also known as noradrenaline, is a hormone that works with epinephrine in responding to stress. It can cause vasoconstriction (the narrowing of blood vessels).
As for life-extending capabilities, reconstruction of telomere caps come to mind as one possible method, so it likely does that to some aspect. While reading one of Herbert's notes in Amnesia: Rebirth, he states that time travel works very strangely. At times the body does not age but passes through time, or the body ages without having passed any time at all. So telomere reconstruction would be useful. To clarify, telomeres are what contains genetic material. They unravel when cells need to reproduce and it is needed by the RNA/DNA. However, vitae also has some instantaneous healing effects, so other healing methods that come to mind are acceleration of the healing process by creating collagen more quickly.
Putting this here. Might expand on it later.