Caffeine Facts

The Mayo Clinic says most healthy adults can safely consume up to 400 mg of caffeine each day.

Caffeine is a central nervous system stimulant that makes us feel alert. It can also improve our mood and is associated with a reduced risk of depression. It can also increase our adrenaline level, which can leave us more irritable, anxious, and far more emotionally-charged. Caffeine has been shown to improve certain types of memory in some, but not all studies. Controlled amounts of caffeine can boost notable performance gains for athletes. Some studies also indicate caffeine is effective to increase long term memories. Although ingesting too much caffeine makes it difficult to focus on anything.

There is some evidence that caffeine, when combined with certain pain-relieving medications like acetaminophen, the main active ingredient in Tylenol, and aspirin, helps those medications take effect quicker, last longer, and increases their effects. Excedrin contains caffeine.

Here are a few common sources of caffeine:

Most 12-ounce cups of coffee contain 90 to 120 mg of caffeine,
One 12-ounce cup of Starbucks contains about 260 mg,
Dunkin Donuts has 215 mg,
One 2-ounce shot of 5 hour energy contains about 215 mg,
One 12-ounce cup of McDonald's coffee has about 109 mg,
One 8-ounce can of Red Bull contains 80 mg,
One cup of brewed black tea contains about 67 mg,
One shot of espresso contains about 71 mg, (a latte is espresso plus steamed milk - cappuccino is espresso plus milk and foam),
One 12-ounce can of diet Coke has 46 grams of caffeine,
One 12-ounce can of regular Coke has 34 grams of caffeine.