An NAD supplement can raise a laboratory marker without making a workout easier. To evaluate exercise claims, look for a measured performance outcome in people with a training background and health status similar to yours.
Two human trials often cited in this area studied different questions: NMN alongside training in recreational runners, and NR for walking limitations in peripheral artery disease. Neither was a trial of a post-workout NAD+ injection.
Some exercise findings justify more research, but they do not establish a universal recovery supplement or a benefit from NAD+ shots.
What happened in the running study?
A 2021 randomized trial assigned 48 recreational runners to placebo or one of three NMN amounts for six weeks, alongside regular training. Some ventilatory-threshold measures improved more in the higher-dose groups, while maximum oxygen uptake did not show the same improvement. The distinction matters: a change in one exercise-test threshold is not evidence that every aspect of fitness improved. The study was small and short, and does not establish an optimal supplement routine.
What did the walking trial find?
The 2024 NICE trial enrolled 90 people with peripheral artery disease. At six months, NR alone produced a 17.6-meter advantage over placebo in six-minute walking distance. This met the trial’s prespecified, relatively permissive one-sided significance threshold of P < 0.10; the reported P value was 0.08. NR plus resveratrol did not meet that endpoint. These are disease-specific findings, not a demonstration that adding NR makes a healthy runner faster.
Endurance, strength, and recovery are separate outcomes
“Performance” can mean a timed walk, a maximal exercise test, lifting strength, or the ability to train again after soreness. Before accepting a recovery claim, ask whether the study actually measured that outcome. A blood NAD increase cannot stand in for less muscle damage, faster healing, or improved race times. Our guide to reading NAD research explains how to match a headline to the endpoint.
Why the delivery route still matters
An oral NMN capsule and an NAD infusion expose the body to different ingredients through different routes. A provider should supply evidence for the service being sold if it promises athletic recovery. There is no established conversion from an oral research amount to an injection schedule. Compare NAD, NMN, and NR before comparing milligram numbers across a clinic menu.
How to assess an offer without chasing a marker
Write down the practical goal before purchasing: for example, completing an ordinary walk more comfortably or returning to an existing training schedule. Ask what competing explanations could affect the result, including training changes, illness, sleep, or other supplements. A favorable personal experience can be meaningful to you while still being uncertain evidence about the product. New exercise intolerance deserves evaluation, rather than an assumption that NAD is low.
What to compare next
For fatigue outside exercise, start with NAD and everyday energy. For products, use the supplement comparison and quality-testing guide. If you have a diagnosed circulation problem, decisions about activity and treatment belong with the clinician managing that condition; this research does not replace that plan.
Sources & reading notes
Primary sources checked September 18, 2026. Provider pages describe their own offers; inclusion does not verify a product or its results.
- Liao et al. (2021): NMN and training in recreational runners Six-week trial in 48 runners; selected threshold measures improved, without a corresponding VO2max benefit.
- McDermott et al. (2024): NICE randomized trial in peripheral artery disease Disease-specific walking trial; prespecified one-sided P < 0.10 threshold, not proof of athletic recovery.
- FDA: questions and answers on dietary supplements Regulatory categories and limits of premarket review.
Educational information, not individualized medical advice. We do not claim medical review or firsthand treatment experience. Read our review standards and commercial disclosure.