In human blood kept alive in a lab, a form of vitamin B3 called nicotinic acid boosts a key energy molecule (NAD+) by 170% in 7 hours, while other similar supplements don’t — showing it works directly in blood cells.

What we've found so far suggests that nicotinic acid may increase NAD+ levels in human blood cells more effectively than other vitamin B3 forms like NR, NMN, or nicotinamide. Our analysis of the available research shows this is based on lab studies using human blood kept alive outside the body. We reviewed evidence from one assertion, which reports that in human blood cells maintained in a lab setting, nicotinic acid increased NAD+ levels by 170% within 7 hours [1]. This effect was observed directly in the blood cells, and under the same conditions, other common NAD+ precursors—such as NR, NMN, and nicotinamide—did not produce the same result [1]. The data we’ve seen so far comes entirely from this single experimental setup, and no studies in our current review have reported results that contradict it. It’s important to note that these findings are based on blood cells in a controlled lab environment, not in living people. We don’t yet know if this effect holds true when nicotinic acid is taken orally or how it might compare over longer periods. Our current analysis does not include data on absorption, metabolism, or long-term changes in NAD+ levels in humans taking these supplements. The evidence we’ve reviewed leans toward nicotinic acid having a strong and direct effect on NAD+ levels in human blood cells under lab conditions. However, we don’t have enough evidence to say how this translates to real-world use. Practical takeaway: In lab tests, nicotinic acid boosted NAD+ in blood cells quickly, while other forms didn’t—but we don’t know yet if that means it’s the best choice for people taking supplements.