Cognitive Decline & Brain Health
Exercise is the strongest cognitive intervention in the human trial literature. Everything else supports it.
At a glance
The letters on this page
Eleven interventions on this page. Nine carry a letter; two are listed without one, with the reason.
How it is measured
What has been graded
Grades reflect the strength of human trial evidence for cognitive outcomes specifically. A compound can grade well for one endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score. and poorly for another.
Among the strongest human evidence of any lifestyle intervention for cognitive and brain health. Hippocampal volume RCT Randomized controlled trial: people are assigned to the treatment or a comparison by chance, so the groups differ only in what they received. It is the design that can show cause and effect. (Erickson 2011, PMID 21282661). BDNF upregulation. Reverses age-related hippocampal shrinkage in older adults. No supplement on this site carries comparable evidence for this endpoint.
Multiple RCTs confirm cognitive benefit in older adults and in sleep-deprived states. Particularly relevant over age 60 and for vegetarians who have lower baseline creatine stores.
MIDAS trial: DHA improved memory in healthy older adults with low dietary DHA. DHA is the primary structural fatty acid in neuronal membranes. Algae-derived preferred.
Multiple RCTs in aging adults show improved memory and attention. Supports phosphatidylcholine synthesis and acetylcholine production.
FDA qualified health claim for cognitive dysfunction. RCTs show improvement in word recall and memory in older adults with subjective cognitive complaints. Soy-derived is the most studied form.
Mori et al. 2009, PMID 18844328 RCT: significant cognitive improvement in adults with mild cognitive impairment over 16 weeks. Effects reversed after discontinuation, suggesting ongoing use is required.
Blood-brain barrier penetration; early human data.
Not graded for this use. Not separately graded. This specific form has its own evidence base and no authored record yet; the parent compound is graded separately.
Meta-analyses A study that pools the numbers from several trials into one combined estimate. of RCTs show improved working memory at 600mg/day or higher; the 300 to under 600mg range is the dose that underperformed. Onset requires 8-12 weeks of consistent use. Food reduces the GI side effects.
Not graded for this use. Luteolin alone has no randomized trial on cognition; the olfactory trials tested a palmitoylethanolamide combination and the one luteolin-alone trial was in Gulf War illness. No letter.
Two small single-dose trials from one laboratory (PMIDs 25018057, 27351678); daily low-dose use for cognition is untested, D Route 1.
Cautions
- •Anticholinergic medications (diphenhydramine, oxybutynin, certain antidepressants) are associated with cognitive impairment and higher dementia risk. Deprescribing is a decision for your physician.
- •Benzodiazepines are associated with higher dementia risk with long-term use. Stopping abruptly carries its own risks, and tapering is a decision for your physician.
- •Randomized trials do not show a consistent adverse cognitive effect from statins. Rare, usually reversible cognitive symptoms have been reported after starting or changing therapy; discuss new symptoms with your physician.
- •Long-term metformin is associated with lower vitamin B12, and B12 deficiency can cause cognitive symptoms that may improve when it is corrected.
This page is educational only. New or worsening memory concerns, confusion, personality changes, or functional decline require clinical evaluation before any supplement protocol. The full medication list can be checked with the Drug-Nutrient Depletion tool. Anticholinergic burden is often the most actionable intervention.
Disclosure
These statements have not been evaluated by the Food and Drug Administration. Any grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.