Up to 24 weeks, NMN caused no more side effects than placebo
Fifteen trials at 250 to 2,000 mg a day found no excess of adverse events, serious ones or dropouts, and no rise in liver enzymes. The longest ran 24 weeks.
What the study found
Out to 24 weeks, NMN's side-effect record matches placebo
Fifteen randomised trials at 250 to 2,000 mg a day, pooled, found no excess of adverse events, serious ones or dropouts, and no rise in the liver enzymes ALT or AST. A separate study cleared 1,250 mg a day for four weeks. That is a clean short-term record for a product sold for life.
The caveat · Too few to catch a rare harm
The longest trial in the pool ran 24 weeks. Ten trials contributed to the safety analysis, too few to catch a harm affecting one user in a thousand, and most were funded by manufacturers, who historically under-report adverse events. The four-week study establishes the highest dose formally tested, not a dose any regulator has certified. No trial measured a cardiovascular event.