What is caffeine?
Caffeine is a natural element found in the leaves or seeds of coffee and cocoa beans, kola nuts, and tea leaves. People often drink coffee, tea, or energy drinks that contain caffeine for caffeine's stimulating effect on the body. After you drink or eat a food that contains caffeine, you may feel more alert and able to concentrate better. Many people drink beverages with caffeine to help them feel more awake in the morning.
How much caffeine is in beverages and food?
Caffeine is found in many types of drinks and in chocolate. Some medicines for pain relief and weight loss also contain caffeine.
Average amount of caffeine in drinks, per serving
- Black tea, 8 oz = 48 mg
- Chocolate milk, 8 oz = 3 mg
- Coffee, brewed, 8 oz = 95 mg
- Energy drinks, 1 can = 75-300 mg
- Espresso, 1 oz = 63 mg
- Green tea, 8 oz = 29 mg
- Hot chocolate, 8 oz = 5 mg
- Regular or diet colas, 12 oz = 19-70 mg
Average amount of caffeine in chocolate, per serving
- Milk chocolate, 1 oz = 6 mg
- Dark chocolate, 1 oz = 16 mg
How does caffeine affect your health?
People react to caffeine in different ways. In general, caffeine stays in your body for at least 6 hours. Some people are more sensitive to it than others. For example, some people drink coffee all day long and still get a good night's rest. Others feel the effects of caffeine longer. This can lead to sleepless or restless nights.
After ingesting caffeine, people who are sensitive to it may:
- Have a faster heartbeat.
- Get a headache or an upset stomach.
- Feel more nervous or shaky.
- Feel dizzy.
If you have bad reactions to caffeine, you might think about cutting back on how much you get in your beverages and food.
How do you cut back on caffeine?
If you decide to lower the amount of caffeine in your diet, think about doing it slowly. If you quit caffeine suddenly, you may have headaches and muscle aches and may feel tired. Feeling angry or irritable is another common reaction.
You might try:
- Cutting back on caffeine drinks by one cup a day until you reach the level you want.
- Mixing decaffeinated and regular coffee.
- Brewing your tea a shorter length of time.
Current as of: January 5, 2026
Author: WebMD Ignite Staff
Clinical Review Board
All WebMD Ignite education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

