For NAD+ enhancement, niacinamide and ribose (less important to supplement, as may not be rate limiting as to normal endogenous supply) are the way to go, within best taking low dose through the day.
In the end it all goes through niacinamide, within this pathway, so niacin in the end will only be effectively yielding niacinamide indirectly for your purposes anyway. With some liver stress as to the amidation so required (though as long as it is not SR it will not overburden the liver in any significant way; this is why as so explained prior only SR will yield a constant taxation of this high affinity/low capacity pathway, if such is at all accurate - RE: http://www.pharmacol...-hepatotoxicity )
Within that, they key is as well not to overload the conversion pathway to NAD+ as that will engender greater levels of niacinamide available for SIRT1 inhibition - obviously undesirable.
(to clarify if any confusion here, anything that gets one to excessive niacinamide, which has to happen to get to NAD+, will engender the SIRT1 inhibition)
The way to 'top it off' effectively, above this, within saturation of the pathway, and the need to avoid the aforementioned excessive levels of NAM, is to supplement with pure NAD+ (I think I heard someone say this before )
This is best done in a manner that bypasses the gut, as NAD+ may survive the gut to some degree (it does have some reasonably stability in acidic media), but certainly bypassing the gut, and first pass as well, would be most optimal. That leaves injections (best, but less viable for most), intranasal, and subligual/buccal (as prior stated).
NR in essence as to supplemental use is simply overpriced SR-niacinamide/(ribose) (as likely the ribose is in adequate supply, though perhaps it assists). It is as seemed noted prior what Logic pointed out fully hydrolyzed in a SR fashion, so all seems pretty simple as to that. A lot to pay for sustained release of very inexpensive substrates.
Notably, I am aware of an entity that can make an orally bioavailable SR niacinamide/ribose/NAD+ product, if enough people have some heavy interest. This entity already has a proprietary established technology to achieve this. Likely be quite a bit more of course that just going by the aforementioned recommendation, albeit somewhat more effective and easy for compliance.
Anyway, again it appears NR itself can be effectively (and far more economically) mimicked by SR-niacinamide, or simply taking niacinamide throughout the day, perhaps best with some ribose, which certainly could not hurt, is cheap and available enough - a 'better safe than sorry' means to ensure an adequate supply.
Stated all this more or less before, but reiterating, in case anyone wishes to make a clear argument against it.
Edited by VERITAS INCORRUPTUS, 17 November 2014 - 03:08 AM.