Mental Energy to Power your Day - Vivarin helps restore mental alterness or wakefulness when experiencing fatigue or drowsiness. Vivarin is simply caffeine--one tablet is equal to one cup of coffee--with no added sugar or calories. Vivarin is safe and effective. Vivarin provides mental alertness that helps you power your day. It has about as much caffeine as a cup of coffee but costs less than a quarter per tablet. So if youre tired of coffee and those unfamiliar ingredients in expensive energy drinks, revive with Vivarin!