You can measure blood D-BHB with a simple blood finger prick (we recommend using a Precision Xtra or Keto Mojo) after 30 minutes.
You can also detect a rise in blood ketones using urine ketone test strips or a ketone breath analyzer.
You may notice a subjective difference during exercise, which may translate into an objective improvement in performance.
Even if you don't exercise, many people report feeling positive subjective cognitive effects within 30 minutes and for upwards of 4 hours after drinking H.V.M.N. Ketone Ester. This includes suppressed appetite, mental clarity, and energy.