Taking a 250 mg NMN supplement every day for a few weeks might boost a key molecule in your blood that helps your cells make energy and slows down some aging effects.

What we've found so far is that the evidence we've reviewed leans toward the idea that taking 250 mg of NMN daily for 6 to 12 weeks may increase NAD+ levels in healthy older men. Our analysis of the available research shows support for this effect, with 48.0 assertions indicating a potential boost in NAD+, a molecule involved in cellular energy production and metabolic health [1]. No studies in our review refuted this effect. We looked at the data to see how NMN—a compound the body uses to make NAD+—might affect NAD+ levels over several weeks. What we’ve seen so far suggests that daily intake of 250 mg of NMN could raise NAD+ levels in the blood [1]. This is meaningful because NAD+ declines with age and is linked to how well our cells function. However, we base this only on the assertions we’ve analyzed, and we don’t yet have full details on study designs, participant health markers beyond NAD+, or long-term effects. Our current analysis does not confirm how much NAD+ increases, how long the effect lasts, or whether this translates to noticeable health improvements. We also don’t have evidence on whether the effect is the same across different ages, diets, or activity levels. Since all the reviewed assertions support the idea and none contradict it, the balance of evidence leans in this direction—but that doesn’t mean the picture is complete. As we continue to analyze new data, our understanding may change. For now, what we can say is that the available evidence points toward a possible increase in NAD+ with this dose and duration of NMN supplementation in healthy older men. If you're considering NMN, it may be worth discussing with your healthcare provider, especially to understand how it fits with your overall health plan.