Medically reviewed by Sohaib Imtiaz, MD A 12-ounce cup of matcha tea made with 2–4 grams, or one-half to 1 teaspoon, of ...

The caffeine in a cup of tea can vary according ... Most research suggests that the rare cases of liver injury from green tea extract consumption are idiosyncratic reactions.

Starbucks refreshers may not be a classic cup of hot coffee, but that doesn't mean they don't have any caffeine. Here's why ...