Alertness

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A glass of grapefruit juice and a mug of coffee on a counter, symbolizing the extended effects of caffeine due to grapefruit juice.

Grapefruit Juice Inhibits Enzymes, Extending Caffeine's Effects

A single glass of grapefruit juice can extend the stimulating effects of your morning coffee by over 30%, potentially keeping you alert for hours longer than expected.

Shira Golan·May 26, 2026