How is SL-NAD+ absorbed, and does it actually enter cells?

SL-NAD+ is absorbed rapidly under the tongue directly into the bloodstream. Once in the bloodstream, NAD+ may be taken up by cells through various mechanisms like active transport or passive diffusion. Our pharmacokinetic studies have shown that NAD+ can directly enter cells, likely through mechanisms such as connexin 43 hemichannels and other solute carrier channels.