According to Mayo Clinic, the maximum amount of caffeine you should have in one day is 400 milligrams.
As one 8-ounce bottle of Boost Energy has 75 milligrams of caffeine, you can safely consume up to five bottles in a day before reaching the maximum recommended caffeine intake.
However, it's important to note that drinking excessive amounts of sugar-free energy drinks can increase your risk for health problems such as headaches, sleep issues, and anxiety.
Therefore, keeping your intake at or below the recommended level is always best.