NAD+ and Mitochondria: What to Know Before Spending Money on NMN and NR

After age forty, you may feel that your energy is not what it used to be. You wake up tired, get more winded than before when climbing stairs, and want your body to keep carrying you through travel, playing with your children or grandchildren, and independent living for longer. Then you open social media and see ads for NMN and NR supplements saying they can help make your “cells younger.” The price is high, and the question that stays in your mind is how much of it is true.

This article summarizes the evidence that has been checked, while stating plainly which parts are clearly supported and which parts are still being debated.

What NAD+ and mitochondria do in your body

NAD+ is a central molecule in cells that performs two functions at the same time. The first is helping produce ATP energy through the electron transport chain. The second is serving as a precursor for three groups of enzymes that maintain cells, namely Sirtuins, which regulate genes and mitochondria, PARPs, which repair DNA, and CD38, which consumes NAD+. When CD38 consumes a large amount of NAD+, the remaining groups have less available to use. Cellular repair therefore worsens accordingly. This mechanism is clearly supported by several independent sources.

Mitochondria are the power plants of cells. Part of the fatigue that comes with aging comes from the accumulated decline of these power plants. The reason is that their DNA (mtDNA) sits close to a source of free radical production and lacks protective shielding as strong as the DNA in the nucleus. As a result, it accumulates mutations about 10 to 100 times faster. This is also clearly supported.

How NMN and NR are different

NMN and NR are both precursors of NAD+. Put simply, they are raw materials the body uses to make NAD+. Research in 2026 found something that changed the previous understanding. Most NMN and NR are not absorbed directly and converted into NAD+. Instead, gut microorganisms first convert them into nicotinic acid, which is then used to make NAD+ in the liver. This means each person’s gut may respond differently to the same supplement.

3 things advertisements often do not tell you

Trust comes from stating limitations directly. These three points are where the research is still conflicting.

Point 1 The numbers on NAD+ decline with age are overstated Advertisements often say that between ages 40 and 50, NAD+ drops by half, and that it falls below 10% by age 80. The reality is that in men aged 40 to 49, it decreases by about 3.4% per year, gradually, not suddenly by 50%. In women, many studies do not find this decline at all. As for the claim that it “falls below 10% by age 80,” there is no supporting evidence. Age-related NAD+ decline remains what researchers call a “confused consensus.”

Point 2 Direct NMN absorption through a specific transporter has not been confirmed in humans NMN does have a transporter called Slc12a8, but the original study was conducted only in mice, and some groups of scientists have criticized the reliability of the data. A 2025 study also found that most NMN in the gut is converted by microorganisms first, rather than being absorbed directly.

Point 3 Whether NR or NMN is better still has no answer Two comparison studies in 2026 produced conflicting results.

Study	Sample	Result
Berven and colleagues (iScience)	6 people	NR increased NAD+ by 161%, while NMN increased it by 67% (NR was about 2.3 times higher)
Cuenoud and colleagues (Nature Metabolism)	65 people	NR and NMN both increased NAD+ by about twofold, with no significant difference

The first study had a small sample but independent researchers. The second study had a larger sample and a control group, but was funded by a supplement company. The conclusion is therefore “still unclear,” not a definitive answer in favor of either side.

What to remember, and the first step

The strongest evidence is the cellular mechanism. The parts that remain unclear are the numbers used in advertisements and the question of whether NMN or NR is better. If you are considering these supplements, take this information to discuss with your physician before spending money, especially if you have an underlying medical condition or are taking medication. This is not medical advice. The decision belongs to you and your physician.

The first step you can take today without waiting for supplements is to try walking for 10 minutes after dinner and add more movement that works your muscles each week. Exercise is a way to care for mitochondria that you can start right away, costs nothing, and has longer-standing evidence than any supplement.

This summary is information for understanding only, not medical advice, and should be reviewed by a qualified professional before being put into practice. The full version includes the complete rationale and research