Kill Cliff energy drink cans

As energy drinks get more popular, more people are asking what’s actually in them. Some contain ingredients you may want to avoid. Bucked Up has deer antler velvet, which many sports leagues ban as a performance enhancer. A 16 oz Rockstar original packs about 60 g of sugar. Bang never said how much “Super Creatine” went into its blend. Reign uses synthetic caffeine. So I set out to find out whether there’s a genuinely healthy option on the market.

My recipe for a healthy energy drink is simple:

  1. No blatantly unhealthy ingredients (duh).
  2. Caffeine from natural sources.
  3. A healthy sugar substitute.

Caffeine itself isn’t on the list. Moderate caffeine intake is considered safe for most healthy adults; the FDA cites 400 mg a day as an amount not generally associated with negative effects, and no common energy drink exceeds that in a single can.

One energy drink clearly meets all three requirements: Kill Cliff. It has no questionable ingredients, three kinds of electrolytes, plenty of B vitamins, and caffeine from green tea extract. It even has Panax ginseng root powder, an adaptogen that may help your body handle physical stress.

Plenty of energy drinks share that base of ginseng, electrolytes, vitamins, and green tea caffeine, so why is Kill Cliff a step above? On top of skipping anything harmful, it has the cleanest sweetener lineup of any common energy drink: zero sugar and no sucralose, which some research links to inflammation and fewer good gut bacteria.

The three sweeteners

Erythritol. The primary sweetener. Each can has 14 g of sugar alcohols from erythritol and inositol. It occurs naturally in some fruits, has about 6% of the calories of sugar, and doesn’t spike blood sugar or insulin. Stomach upset is the main side effect, and it usually takes 40 g or more to cause it. In other words, one or two cans a day shouldn’t bother you; three or four might.

Note (2026): Since this article was written, a 2023 Cleveland Clinic study linked high blood levels of erythritol to a higher risk of blood clots, heart attack, and stroke. The research is ongoing, but if you have heart-disease risk factors, it’s worth asking your doctor about.

Inositol. A sugar alcohol found naturally in brain tissue and common in over-the-counter supplements. It’s being studied for hormone balance, mood, and insulin sensitivity, and its side effects are similar to erythritol’s.

Stevia. Because there’s so much erythritol and inositol, Kill Cliff only needs a little stevia. It’s a zero-calorie sweetener considered safe in the amounts used in food and drinks.

The upshot

Kill Cliff gets the ingredients right in nearly every category: nothing blatantly unhealthy, excellent sweetener choices, and caffeine from green tea. It’s also delicious and refreshing, with plenty of flavors to choose from. If you want a can you won’t feel bad about, Kill Cliff is it.

Looking for more lower-sugar picks? Our rankings let you sort every drink by caffeine, and the Gatorade Fast Twitch rankings cover another zero-sugar option.