This buzz may keep you awake at night, but it won't sober you up if you've been drinking. Caffeine also stimulates the flow of stomach acid, so avoid it if you're susceptible to ulcers . Experts disagree, but many studies show that caffeine junkies do experience withdrawal symptoms, including headaches , drowsiness, and a lack of concentration, when they miss their fix. Kids can get hooked, too. Cutting back gradually can help you avoid symptoms.
Instant kinds provide only half as much.
A typical cup of brewed tea contains about 40 mg, although some brands can have as much as coffee. A can of soda contains around 35 mg, a mug of cocoa only 5 mg. A 1-ounce square of milk chocolate also averages 5 mg, but dark packs 20 mg. Many medications, including some pain relievers, cold and allergy remedies, and appetite-control pills, contain caffeine as well. That's not a problem for cafi au lait fans, but it could be worrisome for postmenopausal women who drink their coffee black and don't get enough calcium.