He owns part of the company that makes patented NMN which is just another form of NR which is a another form of very cheap Niacin.
He also owns part of the company that claims he is rolling back his biological clock.
That's not science, that's marketing and profiteering.
NAD production slows down with age and illness. All he is doing is supplementing what was produced more easily by a younger body.
There are a many other factors to aging, most of which cannot be changed (yet) by science.