For most healthy adults, consuming up to 400 milligrams of caffeine per day is generally considered safe and not associated with negative effects. This amount is roughly equivalent to two to three 12-ounce cups of coffee or about four cups of brewed coffee
. However, individual sensitivity to caffeine varies widely due to factors like genetics, health conditions, medications, and pregnancy status
. Consuming caffeine above this level can lead to unpleasant symptoms such as nervousness, jitteriness, anxiety, irritability, headaches, and even more serious effects like heart palpitations or seizures in extreme cases. Toxic effects may begin around 1,200 milligrams consumed rapidly, and pure caffeine powder is particularly dangerous because even small amounts can be lethal
. Special populations should be more cautious:
- Pregnant or breastfeeding women are advised to limit intake to less than 200 mg per day
- Children and adolescents should avoid caffeine or consume it very sparingly, especially avoiding energy drinks
- People with anxiety or certain medical conditions may need to limit caffeine further due to increased sensitivity
In summary, up to 400 mg per day is the upper limit for most adults , but individual tolerance varies, and exceeding this can cause negative health effects. Extreme overdoses are rare but can be dangerous or fatal
