Higher NAD+ levels: a marker or a benefit?

What a biomarker actually tells you

A biomarker is a measurable characteristic used to investigate biology or disease. In NAD+ research, investigators can measure NAD+ or related metabolites in a specified sample. A change can show that an intervention affected the pathway being studied. It does not automatically explain how someone feels, whether they function better, or whether their long-term risk changed.

That distinction is easy to lose in a product headline. Boosts NAD+ and improves health sound like neighboring statements, but the second requires additional evidence. A laboratory result is most useful when the seller identifies exactly what was measured, where it was measured, when it was measured and how the comparison group behaved. A percentage without those details is difficult to interpret.

An example from a randomized NR trial

Conze and colleagues studied oral NR over eight weeks in healthy overweight adults. The trial reported a rise in whole-blood NAD+ and assessed adverse events. It provides evidence about a measured biochemical response over a defined period. Its results should not be rewritten as proof that buyers will gain more energy or live longer.

The study also disclosed funding and author relationships involving the ingredient manufacturer. A disclosed commercial relationship does not erase the result, but it belongs in the evaluation. Look at study design, predefined outcomes, missing data and independent replication rather than treating either industry funding or a reassuring headline as the whole answer.

Primary outcomes and exploratory results

Researchers often identify a primary outcome before a trial starts. This is the main question the study is designed to answer. Secondary and exploratory outcomes can be valuable, but a trial that measures many things has more opportunities to find a result that looks interesting by chance. An isolated change deserves careful wording and confirmation.

The 2025 Wu NR crossover trial in adults with cognitive concerns provides a concrete example. The researchers reported a change in the plasma biomarker pTau217, but did not find an improvement in cognition on the assessments used. Those findings should remain separate in a consumer summary. A favorable signal in a blood test cannot be quietly substituted for an improvement in memory.

Why before-and-after testimonials fall short

Someone can feel better after a purchase for several reasons: ordinary variation, expectation, changes in sleep or exercise, another treatment, or the intervention itself. A personal report cannot separate those explanations. A well-designed comparison group helps investigators estimate which changes are attributable to the intervention under the conditions tested.

The same problem applies to a laboratory test purchased with a supplement. Two measurements can differ without establishing a clinically useful improvement. To make the claim useful, a seller should explain how the result changes a decision and why that decision improves an outcome. A graph showing an upward line is only the beginning of that argument.

A practical way to read a claim

Rewrite the headline as a testable sentence. Name the product, the people, the duration, the comparator and the outcome. For example, a trial might show a measured blood response in a defined population over several weeks. If the advertisement instead promises everyday energy for everyone, the missing steps become visible immediately.

The most useful study summary includes uncertainty. Ask whether the observed difference was large enough to matter, whether the results were consistent, and whether the outcome was measured in a way that addresses your concern. A statistically significant result can still be narrow, preliminary or unrelated to the benefit being sold.

• What was the study's main outcome?
• Was the finding different from placebo?
• Was it a laboratory value, a symptom score or a clinical event?
• Does the seller preserve the study's population and duration?

Sources and scope

These are selected studies and official sources relevant to the question above, rather than a systematic review of every published paper. A finding applies to the people, ingredient, route and outcomes studied. This guide provides education, not a diagnosis or medical advice. Discuss personal treatment decisions with a licensed clinician.

1. Conze D and 2 others, Safety and Metabolism of Long-term Administration of NIAGEN (Nicotinamide Riboside Chloride) in a Randomized, Double-Blind, Placebo-controlled Clinical Trial of Healthy Overweight Adults. Sci Rep, 2019. PubMed 31278280. Read the PubMed record
2. Wu CY and 16 others, Cognitive and Alzheimer's disease biomarker effects of oral nicotinamide riboside (NR) supplementation in older adults with subjective cognitive decline and mild cognitive impairment. Alzheimers Dement (N Y), 2025. PubMed 39817194. Read the PubMed record

Continue reading

• Understanding NAD+ blood tests

  Sample types, reference intervals and practical questions to ask before paying for a laboratory package.

• NAD+ for energy and fatigue

  Read the fatigue and function outcomes behind energy claims, with the placebo comparisons kept in view.

• NAD+ and anti-aging evidence

  Separate short human trials, laboratory findings and lifespan promises before evaluating a longevity claim.

All NAD+ research guides