Ketone ester is the highest quality form of exogenous ketones. It is 100% Bioavailable and made through a 100% natural process. Our first drink was called KE4 Pro. It is super concentrated and tough to drink straight. Our newest drink is called KE1 which is more dilute but MUCH easier to drink. Ketone esters first came onto the screen secretly during the Tour De France as early as 2015 and the secret came out in 2019.