What to Stack With NAD+ Precursors, and What to Skip

Stacking is where most people's NAD+ routine stops being an experiment and starts being a shopping habit. There are one or two additions with a coherent rationale. There are several with a rationale that evaporates on inspection. And there is a cost to adding any of them that nobody mentions: you lose the ability to tell what is doing anything.

The methylation question (the one worth taking seriously)

This is the most substantive argument for adding something, so it deserves a proper hearing.

When your body clears excess nicotinamide, one route is to methylate it — attach a methyl group — producing methylnicotinamide for excretion. Methyl groups come from a shared cellular pool used by many other processes.

The concern follows naturally: if you take large daily doses of a precursor for months, are you drawing down that methyl pool faster than usual? Supplementing a methyl donor such as trimethylglycine — betaine, often sold as TMG — is the proposed remedy.

The honest status: the pathway is real and the reasoning is sound. Whether it produces a meaningful methyl deficit in practice, at the doses people actually take, has not been well demonstrated in humans. It is a plausible concern with thin evidence, not an established problem with an established fix.

TMG is cheap and well tolerated, which is why many people add it as insurance rather than as treatment. That is a defensible position provided you are honest that insurance is what it is.

The ones with weaker cases than you would think

Resveratrol

Paired with NAD+ precursors on the logic that it activates sirtuins, so the two work together. The direct-activation claim rests on early work using a fluorescent-tagged substrate, and the apparent effect appears to depend on that tag. Whether resveratrol meaningfully activates sirtuins in a person is contested. The pairing is a habit the market inherited from a story that did not hold up. Covered further in the sirtuins page.

Flavonoids marketed as CD38 inhibitors

Compounds including apigenin and quercetin do inhibit CD38 in laboratory conditions, and since CD38 is the main NAD+ drain, the logic is appealing. The gap is concentration: the amounts that inhibit CD38 in a dish are generally far above what oral supplementation produces in tissue. The mechanism is real; that your capsule achieves it is not shown.

Everything described as "synergistic"

Synergy is a specific, testable claim: the combination does more than the parts added together. It is rarely tested for supplement combinations and almost never demonstrated. In practice the word usually means the two products are sold together.

The real cost of a big stack

Set the biochemistry aside, because this is the argument that should actually decide it.

If you begin four things at once and feel better six weeks later, you have learned almost nothing. You cannot attribute the change, you cannot drop the one that is doing nothing, and you will likely keep paying for all four indefinitely. If you feel nothing, you do not know whether one component was working and another was offsetting it.

Add to that the ordinary failure mode: the more items in a routine, the more likely it is abandoned. A four-item stack is four chances to run out, forget, or decide the whole thing is too much effort. Adherence is the variable that actually predicts outcomes, and complexity is its enemy.

A sensible sequence

1. One precursor, alone, for ninety days. Written expectations set before you start. This is your baseline and nothing else changes.
2. Add TMG if the methylation reasoning persuades you. It is inexpensive and the rationale is the strongest of the available additions.
3. Stop there unless you have a specific question. "It was in a stack I read about" is not a specific question.
4. Change one thing at a time, and give each change a real trial. Slower, and the only way you end up knowing anything.

Related: When to take your dose · How long to trial it · Sirtuins