When you add a vitamin called nicotinamide riboside to gut bacteria in a lab, the bacteria turn it into another helpful compound, and this happens the same way in everyone — no matter their age or health condition.

What we've found so far is that gut bacteria can convert nicotinamide riboside into another compound when tested in lab settings. The evidence we've reviewed leans toward this conversion happening consistently across individuals, regardless of age or health status. Our analysis of the available research shows that when nicotinamide riboside is introduced to gut bacteria in a controlled lab environment, the bacteria transform it into a different compound [1]. This process appears to occur in a uniform way, based on the data we’ve examined [1]. We do not have evidence suggesting variation in this process due to personal factors like age or health condition [1]. The current analysis is based on a single assertion drawn from laboratory studies, and while the supporting weight is high (67.0 supporting instances, 0 refuting), we are limited to what has been observed in cultured settings, not in living humans. This means we cannot yet say how this process might function in the complex environment of the human gut. We also do not have data on whether this conversion leads to meaningful changes in health or metabolism. Because our findings are based on in vitro (lab culture) studies, we cannot extend these results to real-world human outcomes with confidence. There may be factors in the human digestive system that affect this process in ways not captured in a petri dish. The practical takeaway: if you're taking nicotinamide riboside as a supplement, gut bacteria in lab tests change it into another compound, but we don’t yet know how this plays out in the body or what it means for your health.