Instapundit links ArsTechnica about a study Rand Simberg linked in Time. The quote from ArsTechnica:
The team behind the paper used human embryonic kidney cells (which grow well in the lab) to look at the role of this chemical. The authors found that NAD+ binds to the protein “deleted in breast cancer 1” (DBC1), which—as its name implies—was previously implicated in cancer. DBC1 normally binds to and inhibits another protein that performs DNA repair. But NAD+ blocks this interaction, releasing the inhibition on DNA repair.
Therefore, as NAD+ concentrations decline with age, it’s possible there is insufficient NAD+ to bind to the DBC1 protein, leaving it free to block DNA repair.
To test this proposed mechanism in a living organism, the authors used aging mice. As expected, NAD+ concentrations declined as the mice aged. With its decline, DBC1 was increasingly binding to and shutting down the DNA repair enzyme. The authors then gave the mice the chemical precursor to NAD+, which should restore their NAD+ concentrations. Once the mice were given this treatment, their DNA repair activity increased, and the levels of DNA damage were reduced.
On the strength of Rand's link and comment, I headed over to one of the local pill stores yesterday and got a bottle. This morning I noticed a great deal of improvement in my overall energy level -- but it's way too soon for this stuff to have made a difference.