The primary outcome remained negative
A 2026 phase II pilot tested NR against placebo for twelve weeks in adults with amnestic mild cognitive impairment. Forty-two participants completed the study: twenty-two receiving NR and twenty receiving placebo. Blood NAD doubled with NR, but the trial found no improvement in cognition, its primary outcome. Total cerebral blood flow and blood pressure also did not improve. [1]
Exploratory analyses suggested possible changes in regional blood flow, particularly the hippocampus. Adherence was similar between groups, and no serious adverse effects were reported. The authors proposed longer research on regional effects rather than claiming a demonstrated cognitive treatment. [1]
Regional and total measurements answer different questions
A whole-brain measure and a regional measure need not tell the same story. That is a reason to label them clearly, not a reason to let the favorable regional observation replace the overall and clinical results. A summary should preserve which analysis was primary, secondary or exploratory.
The hippocampus is a recognizable term in brain-health marketing. Its appearance in a paper can make a small exploratory finding sound like proof of improved memory. The direct cognitive assessment remains the relevant test of that claim in this trial.
An appropriate next study could investigate whether a regional signal is reproducible and whether it accompanies a meaningful clinical effect over time. Until then, the signal should remain a research question rather than a promised benefit.
How this paper fits the evolving evidence
The earlier twenty-person MCI pilot and the pTau217 study also distinguish biochemical or exploratory findings from cognition. Each has its own design and population; they should not be treated as identical experiments.
New publication dates do not automatically make a result stronger. The important update is the additional controlled evidence and the specific question it addresses. Here, the clinical result remains central even though the measured NAD pathway responded.
For a product marketed for memory, ask whether its cited study actually improved a validated cognitive outcome in comparable participants. A higher NAD value, a regional imaging observation and an interesting mechanism are not interchangeable answers.
Concerns about memory or daily functioning deserve clinical assessment rather than self-diagnosis from a supplement article. This paper does not establish an approved use, an individual dosing strategy or prevention of dementia. It adds a clearly defined twelve-week result to an active research area: biochemical response occurred, while the tested cognitive benefit was not demonstrated. That distinction should remain visible in any consumer-facing description of the study. A future positive trial would need its own careful assessment.