Think you can’t start your day without a caffeine shot? You might be deceiving yourself! According to Michael A. Grandner, of the University of Arizona College of Medicine, caffeine doesn’t produce any powerful effects immediately after you take that first sip. That’s mainly due to the way caffeine works in the brain, Grandner added. The effectiveness of caffeine depends highly on timing. Your favorite cup of coffee needs at least 20 minutes to trigger any increases in alertness or performance. So, if you jump out of bed and go straight to the kitchen to get an instant burst of energy, what you experience might only be a placebo response, Grandner says.