Beta-hydroxybutyrate / Exogenous Ketones for Cognitive Function
There is no reliable evidence that beta-hydroxybutyrate or other exogenous ketone supplements improve cognitive function in healthy adults. The few human trials are small, short, and inconsistent, so this use remains unverified rather than proven.
Why this grade7-layer evidence engine
The human trials are sparse and weak. A small acute crossover RCT raised blood BHB above 2 mmol/L but found no consistent cognitive benefit versus placebo (PMID 34605026). The only positive signals came from MCT-based ketogenic regimens in Alzheimer's (PMID 30367958) and mild cognitive impairment (PMID 33103819), small pilot studies in patients, not BHB supplements in healthy people. A 2025 systematic review concluded the evidence is limited and heterogeneous, with cognitive benefits inconsistent in healthy adults (PMID 41001501).
Regulators and clinics do not endorse this use. The US FDA's 'no questions' GRAS responses cover food safety only, not cognitive efficacy, and EFSA found the safety of BHB salts as a novel food not established, with no authorised cognition claims. NHS and WHO have not addressed it. Harvard Health states there are no human studies supporting ketosis for brain disorders, and the Alzheimer's Association says no supplement has been proven to benefit cognitive function or brain health.
The grade is Unverified because the evidence gap is structural, not merely preliminary: no adequately powered, long-term RCT tests BHB-only supplements on cognition in healthy adults, and benefit signals are confined to MCT-based protocols in disease populations that cannot be extrapolated. A drug-interaction flag (notably with diabetes medications) adds caution. The honest conclusion is that it does not have demonstrated cognitive benefit.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.418
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — | C→U 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status