Question: what happens if you drink more than 1 monster?
Answer: Up to 400 mg of caffeine per day is generally safe. Still, drinking more than four, 8-ounce (240-ml) servings of energy drinks per day — or two, 16-ounce (480-ml) cans of Monster — may cause negative effects due to excess caffeine, such as headache or insomnia ( 9 , 10 ).