Which type of exogenous ketone is most effective: a ketone salt, a ketone ester, or a ketone precursor (a pro-ketone)?

While some evidence shows that ketone esters have a greater effect than ketone salts on increasing ketone body concentrations and lowering blood glucose,^[1] not all the studies show this difference.^[2] However, the precise type of ketone being studied is often unclear because the terms “exogenous ketone” and “ketone ester” are used interchangeably to describe isolated ketone bodies (e.g., beta-hydroxybutyrate), ketone esters (e.g., beta-hydroxybutyrate attached to 1,3-butanediol), and ketone precursors (isolated 1,3-butanediol).^[3][4] Consequently, the comparative effects of ketone salts vs. ketone esters vs. ketone precursors (sometimes called pro-ketones) have not been adequately studied to determine which type of exogenous ketone supplement might have the greatest efficacy.