In mice, a supplement called nicotinamide riboside only boosts energy-related molecules if gut bacteria first turn it into a different form—without those bacteria, the supplement doesn’t work.

When mice take NMN or NR supplements by mouth, most of it gets changed into another form—nicotinic acid—by gut bacteria before the body uses it. The liver mostly uses this changed form to make an important molecule called NAD+, and only a little bit gets used directly.

If you take antibiotics that wipe out your gut bacteria, your body can't turn a supplement called nicotinamide riboside into a form that helps make an important molecule called NAD+, so it doesn't work anymore.

Your gut bacteria can turn a form of vitamin B3 from your body into another version that gets reused to make important energy molecules, especially when your body’s usual recycling system isn’t working well.

When you take NR or NMN supplements, your gut bacteria turn them into a form of vitamin B3, which your body then uses to make an important molecule called NAD+ that helps keep your cells healthy.

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.