Prime Energy packs 200 mg of caffeine into a 12 oz can, about as much as two cups of coffee. An occasional can is unlikely to harm a healthy adult, but it is not for anyone under 18, which matters because the brand's audience skews young. It is a different product from caffeine-free Prime Hydration.

Prime Hydration is caffeine free and fine in moderation, but it relies on artificial sweeteners like sucralose and acesulfame potassium. Prime Energy is a different product with about 200 mg of caffeine and is not appropriate for kids or teens.

An occasional Rockstar is fine for most healthy adults. The issues are daily consumption, the 160 mg of caffeine per 16 oz can stacking with your other caffeine, the sugar in the original formula, mixing with alcohol, and any consumption by kids and teens.

A 5-Hour Energy shot has about 200 mg of caffeine plus B vitamins at many times the daily value. Occasional use is unlikely to harm a healthy adult, but jitters, lost sleep, and the niacin flush are real, and energy shots are not for kids.