The recommended dosage by specialists from the FDA is up to 400 mg of caffeine per day. This is approximately equal to 4 cups of 250 ml (8.5 fl oz). Moreover, a single dose should not exceed 200 mg, that is, two cups. This recommendation is for a healthy adult. The reaction varies individually, depending on metabolism and sensitivity to caffeine. Toxic effects in the form of seizures are observed after consuming 1200 mg of caffeine in a short time.