NAD supplementation and exercise: measure performance, not just chemistry

What counts as better performance

An exercise claim should name an observable outcome: how far someone walks, how much power they produce, or how a standardized exercise test changes. A blood marker cannot supply those answers. Even physiological exercise measures are not interchangeable. A result at a ventilatory threshold, for example, does not establish a faster race time or better maximum aerobic capacity. The actual test belongs in the headline.

The six-week runner study

Liao and colleagues randomized 48 recreational runners to placebo or one of three NMN amounts while they completed exercise training for six weeks. The published report describes improvements in selected ventilatory-threshold measures, without an added effect on VO2max. This is a more specific result than a claim that NMN improves all aerobic capacity. Because training occurred across groups, the treatment comparison asks what supplementation added to that program.

Why the training context matters

Recreational runners are already accustomed to exercise, so their results should not be automatically assigned to sedentary older adults or people with medical limitations. The study was also brief and modest in size. A training program can improve performance independently, which makes the placebo comparison essential. Neither a dramatic personal training story nor an improved before-and-after test can isolate a supplement effect without suitable controls.

Older-adult function is a separate endpoint

Igarashi and colleagues studied oral NMN in healthy older men and reported increased blood NAD-related measures and nominal improvements in selected functional tests. They did not find a significant body-composition effect and called for larger validation. Functional outcomes are useful, but isolated nominal findings deserve careful language when several tests are performed. They should not become claims that every reader will gain muscle or improve athletic performance.

How to assess a performance promise

Ask whether the outcome was primary, how large the between-group difference was, and whether a meaningful threshold was specified. Check who completed the trial and whether training exposure was similar. A product advertisement that discusses mitochondria but omits the actual exercise results is leaving out the decision-relevant part. More biochemical detail cannot compensate for an unmeasured performance outcome or a missing comparison group.

Ask whether the difference matters

Statistical significance is not a measure of how valuable a performance change would feel to a person. A very small difference can be statistically persuasive in a large trial, while a promising larger difference can remain uncertain in a small one. Both the absolute effect and its uncertainty deserve attention.

For an athlete, repeatability across training conditions may matter; for someone with limited mobility, a practical daily task may be more relevant than a maximal laboratory test. Neither goal is served by a generic improves performance claim. Choose the outcome first, then assess whether the participants, protocol and measured difference speak to it. This prevents an intriguing laboratory finding from being oversold as a universal training advantage.

Putting the evidence to work

The existing examples support continued research, with claims tied to particular populations and tests. They do not establish supplementation as a substitute for training or as a reliable performance enhancer for everyone. Compare the exact study material with a retail label, including additional ingredients and delivery method. Our format and cost tools can organize a purchase, but neither tool predicts the change in your fitness or chooses a treatment.