It most often comes from plants, commonly coffee beans and tea leaves. But it can also be made in a lab. Caffeine is the most widely used drug in the world. It stimulates your nervous system, and most adults consume it regularly.
What does caffeine do? Well, in small doses, it gives your brain and body a quick boost of energy. It makes you feel more awake and alert. We get caffeine by drinking coffee or tea. It's found in soft drinks, energy drinks and chocolate. Caffeine is also found in places you may not expect. It's in some pain relievers and cold medicines. And, you can find it in pills, gums and snacks made to fight drowsiness.
Is caffeine harmful? For most people, it's safe to have the amount of caffeine found in a few cups of coffee each day. But if you have too much caffeine, or if you're sensitive to it, the side effects can be unpleasant. You can have headaches, dizziness, restlessness and shakiness. Your heart may beat quickly or abnormally. You may feel dehydrated. You may become anxious, and you may have trouble falling asleep at bedtime.
Caffeine isn't right for everyone. If you have a heart condition, kidney disease or chronic upset stomach, or if you are pregnant, you may need to avoid it. For more information, talk to your doctor.