Before You Buy: We Rank the Best and Worst Energy Drinks for Your Health

“Not all energy drinks contain the same ingredients, therefore it’s crucial to read the nutrition label. Some may have high caffeine content, while others may be high in sugar,” says F-Factor founder Tanya Zuckerbrot MS, RD. “Because energy drinks have only recently gained popularity, their long-term effects on organs, such as the liver, cardiovascular disease and diabetes have not been determined.” Zuckerbrot recommends consuming them in moderation until further research is conducted to determine lasting consequences.

You’ll also want to note, says Zuckerbrot, that the caffeine and sugar found in most energy boosters increase blood sugar levels giving an initial energy burst, but this surge is generally followed by a sudden decrease in blood sugar levels, which creates a “crash,” leaving you feeling tired and lethargic. Further, the sugar may lead to weight gain and while moderate caffeine consumption is safe, excess consumption can be addictive. “Caffeine is also a diuretic, so excess consumption can lead to dehydration,” she explains, something you should consider if you’re looking to boost your energy pre-workout.

Clearly, it’s best to get your energy naturally via foods, enough sleep and a limited amount of stress, but we all know that’s not always possible, so we asked Zuckerbrot and two other prominent nutritionists about the pros and cons of some of the most popular energy boosters.