Ketone esters (exogenous ketones)

Tier 2 — promising · Cognitive fuel · Endurance · Metabolic

Exogenous ketone esters (primarily D-beta-hydroxybutyrate monoester) rapidly elevate blood ketone levels to 3–5 mmol/L within 30 minutes without requiring fasting or carbohydrate restriction. Military and elite sport studies show improved cognitive performance under stress and sleep deprivation. Mixed results for endurance performance. Extremely expensive and taste extremely bitter. GI distress is common.

Dose: 25–50 g ketone monoester 30 min before cognitive demand; expensive at 30–50 USD per serving