Safety and tolerability of sustained exogenous ketosis using ketone monoester drinks for 28 days in healthy adults

Twenty-four healthy adults aged 18 to 70 drank 25 ml (26.8 g) of the ketone monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate three times a day for 28 days, a total of 2.1 L. Anthropomorphic measurements and fasting blood and urine analyses were made weekly. Blood beta-hydroxybutyrate rose from 0.1 to 4.1 mM, with no effect on body weight or composition, fasting glucose, cholesterol, triglycerides, electrolytes, blood gases, or kidney function. Mild nausea was reported after 6 of the 2,016 drinks.