Mental Alertness* Sustained Release Caffeine With B Vitamins NOW® Sports Sustained Energy is formulated to supply the nutrients you need to promote sustained energy production and mental alertness.* With a complement of B vitamins and other cofactors such as chromium, magnesium malate and carnitine, Sustained Energy delivers what your cells need most to drive energy production.* This product also has tyrosine and iodine to support optimal thyroid function, plus a blend of immediate and sustained release caffeine to get you going and keep you going.* This product has approx. 120 mg of immediate and sustained release caffeine per serving (equivalent to about 1 1/4 cups of coffee).