It's blood. The elites are using the blood of children. Adrenochrome is just one component in blood and not the one that causes the rejuvenation effect.
Confirmed by science:
https://www.newscientist.com/article/2112829-blood-from-human-teens-rejuvenates-body-and-brains-of-old-mice/
Adrenochrome is a molecule that occurs in humans of all ages. Adrenochrome, being derived from adrenaline, is a stimulant when ingested and gives a rush, but for true medical benefits you need that other stuff in the blood.
Synthetic adrenochrome is probably a lot like synthetic THC - not at all like the real organic blend of chemicals.
The mind set is what cause the adrenochrome to be there in the first place. Adrenaline is your body's natural pain killer responsible for runner's high. Ingesting the adrenochrome that another person's body produced gives a high like your body's natural product never can, because the natural product is never produced without a cause, usually an unpleasant cause.