While some people are more sensitive to caffeine than others, it is generally believed that a healthy adult can enjoy roughly four cups of brewed coffee (400 milligrams of caffeine) a day without any adverse side effects.1 This does not mean that you should up your intake if you are contentedly enjoying less than four cups; however, it is important to identify any negative side effects you may be experiencing (i.e. headaches, irritability, insomnia, etc.) with the amount you currently consume. It may be that reducing your caffeine intake will address these issues.
How many cups do you need to start your day?