A new coffee claims it's the most potent in the world.
"Black Insomnia Coffee" has 702 mg of caffeine inside a 12 oz cup. Researchers with the Mayo Clinic say the coffee may not be safe. They recommend most healthy adults can't consume more than 400 mg a day.
Previously, "Death Wish Coffee" held the title as the most potent with around 660 mg in a 12 oz cup.