Why wait with caffeine ingestion?

Waiting 90–120 minutes after waking lets your natural morning alertness processes work before caffeine blocks adenosine receptors. This can help avoid an afternoon crash and reduce the chance of relying on later caffeine that may disrupt sleep. 1

• 1. Adenosine receptors: Caffeine blocks adenosine’s effects rather than clearing adenosine. Taking it immediately can leave adenosine accumulating, so sleepiness may hit harder as caffeine wears off. 2
• 2. Circadian clock and cortisol: Morning light supports the circadian cortisol rise, which promotes alertness and helps clear residual adenosine. Delaying caffeine leaves that process unblocked, then caffeine can provide an additional lift in alertness and focus. 3 4