Two-year fish oil trial shows supplement reaches brain but doesn't slow cognitive decline

**Summary**

Discussion centers on recent clinical trial results examining whether supplements—specifically fish oil (DHA) and other compounds like GlyNAC—can slow cognitive decline or brain aging in older adults. The primary trial involved 365 older adults at increased Alzheimer's risk who took 2,000 mg/day of DHA for two years. While the supplement successfully reached the central nervous system (confirmed by elevated DHA in spinal fluid), it produced no measurable cognitive benefits or changes in hippocampal volume compared to placebo.

**Dominant Framings**

Reddit users frame these results as a cautionary tale about supplement efficacy: the gap between biological markers (DHA presence) and clinical outcomes (no cognitive improvement) is presented as evidence that reaching the brain doesn't guarantee functional benefit. A secondary discussion questions sample size adequacy, with one user noting that a separate GlyNAC trial showing aging improvements involved only 24 participants—raising questions about statistical power and reproducibility.

**Notable Disagreement**

Engagement is minimal (3 Reddit mentions, no mainstream coverage), and there is no visible disagreement in the available posts. Users appear aligned in treating null results skeptically, though the limited discussion prevents assessment of whether broader audiences contest these findings or interpret them differently.