Ketone Ester BHB at 31 Days Improves Exercise, Cognition, and Mood Together. Single 2g D-BHB Lifts Psychomotor Vigilance
Data are accumulating that exogenous ketones can have clinical meaning even without following a keto diet. A randomized controlled trial published in the Journal of the American Nutrition Association in April 2026 supplemented runners with ketone monoester (KME) 90g/day (30g×3) for 31 days, evaluating exercise performance, executive function, mood, metabolism, body composition, blood pressure, and tolerability. Around the same time, an N=136 RCT directly comparing single-dose 2g D-BHB and L-BHB reported D-BHB outperforms L-BHB in psychomotor vigilance.
Beta-hydroxybutyrate (BHB) is a ketone body produced when fatty acids undergo beta-oxidation in the liver. Blood concentration rises with fasting over 24 hours, ketogenic diets, and intense exercise. The brain can use BHB as an alternative fuel to glucose, opening cognitive support possibilities for patients with insulin resistance and impaired brain glucose metabolism (early Alzheimer’s, some depression).
Existing exogenous BHB came in two forms. First, ketone salts — Na/K/Mg/Ca bound to BHB as powder. Inexpensive but small blood concentration rise (0.5~1 mmol/L). Second, ketone monoester (KME, 1,3-butanediol mono-BHB) — direct BHB precursor that rapidly raises blood concentration to 2~3 mmol/L. Pricier but with clear clinical effect.
The 31-day KME trial results are layered:
- Exercise performance: some metrics improved, others unchanged (mixed results)
- Executive function: cognitive scores partially improved on Stroop and similar tests
- Mood: partial improvement in mood scores
- Metabolism: changes in resting oxidation capacity
- Body composition: little change (no significant change in weight or body fat)
- Blood pressure: stable
- Tolerability: some GI discomfort reported, but over 90% completion
Clinically meaningful areas for women:
-
Menopausal cognitive fog: Brain glucose metabolism efficiency declines after menopause. BHB entering as alternative fuel can partially improve working memory and concentration. Single-dose D-BHB 2g psychomotor vigilance gain is direct evidence of this circuit.
-
Exercise performance support: Sustaining exercise intensity becomes harder for women after 50. KME taken 30–60 minutes before exercise shows performance enhancement in some sports.
-
NAFLD + insulin resistance: BHB raises hepatic fatty acid oxidation and partially recovers insulin signaling. Modest as monotherapy — supports an ALA·inositol matrix.
-
For PCOS / menopausal women avoiding keto diet: The keto diet itself is burdensome (carbs <50g/day, social meal challenges). KME provides partial keto effect without dietary change.
Limitations are clear, too. KME is expensive (₩300,000–500,000/month). Nausea and abdominal pain are intolerable for some patients. Only short-term data — long-term safety data are insufficient. Metabolic adaptation effects of the keto diet itself cannot be replaced by exogenous BHB (mitochondrial adaptation is the core). Not used in pregnancy or lactation.
Recommended use:
- Cognitive support: single-dose D-BHB 2–10g between meals
- Pre-exercise: KME 10~30g, 30–60 minutes before
- Chronic supplementation: KME 30g×2–3/day (price and tolerability make this not generally recommended)
- Keto diet support: KME during fasting periods to accelerate ketosis
A more economical approach is dietary induction of natural ketone production. Intermittent fasting (16:8 or 18:6), 12+ hours of fasting after dinner, 5:2 fasting (50% calorie reduction 1–2 days/week). Protein-focused meals after exercise also produce transient ketone elevation.
Exogenous ketones are one tool in the longevity, cognition, and exercise matrix — not the standalone answer. They take meaning when working alongside NAD+ boosters, ergothioneine, vitamin D, omega-3, exercise, and sleep. For women in their 50s and beyond, exogenous ketones merit review as a cognitive and exercise support option, but cautious adoption considering price and tolerability is reasonable.