In certain cases, taking NAD+ boosting supplements can deplete levels of methyl groups in the body. TMG is one of the most important ways to restore methyl groups because as the name implies, it has three methyl groups to donate
As NAD+ gets used, it is broken down into Nicotinamide (NAM). To get rid of excess NAM, a "methyl" is attached to NAM to form methylnicotinamide (MeNAM) so it can be excreted.
Consequently the more NAD+ that is used, more MeNAM needs to be excreted which can put a stress on the pool of methyl groups, leaving less for other essential methylation functions.