Taking 250 mg of NMN every day for a few months doesn’t change body fat or muscle mass in healthy older guys, even though their muscles may work better.

What we've found so far suggests that taking 250 mg of NMN daily does not improve body composition in healthy older men. Our analysis of the available research shows no meaningful changes in body fat or muscle mass, even though there may be other effects on muscle function [1]. We reviewed the evidence to understand whether this specific dose of NMN affects body composition—meaning fat and muscle levels—over a few months. The data we’ve analyzed so far comes from one key assertion based on 48 supporting studies, with no studies showing a contrary effect [1]. According to this assertion, while NMN may lead to improvements in how muscles work at a cellular level, it does not translate into measurable changes in body fat or muscle mass in healthy older men. Our current analysis shows that the evidence leans toward no impact on body composition with this dose. That means if someone is taking NMN hoping to gain muscle or lose fat, the results we’ve seen so far don’t support that outcome. However, this doesn’t rule out other potential benefits that aren’t related to body composition. We want to be clear: this is what we’ve found based on the evidence reviewed up to now. There may be limitations in how body composition was measured, or differences between individuals that aren’t fully captured. As more data becomes available, our understanding could change. Practical takeaway: If you're a healthy older man taking 250 mg of NMN daily for better body composition, the evidence we’ve reviewed so far doesn’t show it will change your muscle or fat levels.