Is there a dark side to energy drinks?

Whether it’s to wake up in the morning, wind down after a long day at work, or boost performance during a workout, energy drinks and pre-workout supplements are growing in popularity. But are they safe? The answer is more nuanced than a simple yes or no.

Energizing: What are we really talking about?

The term “energizing” encompasses several types of products that do not, however, serve the same purpose.

Pre-workout supplements are designed to be taken before a workout. Their composition varies, but they often contain caffeine, as well as other ingredients such as beta-alanine, citrulline, or creatine.

Energy drinks (Red Bull, Monster, Celsius, etc.) generally contain caffeine, sugar, or sweeteners, as well as other ingredients such as taurine, guarana, or B vitamins.

Warning! Do not confuse these with sports drinks (e.g., Gatorade), which are designed to provide carbohydrates and electrolytes during prolonged physical activity.

How do they work?

Not all energy drinks and supplements provide energy in the nutritional sense. Those containing sugar provide carbohydrates and, therefore, energy. However, the desired “boost” comes mainly from caffeine, which temporarily increases alertness and can reduce feelings of fatigue as well as the perception of exertion. The other ingredients have distinct mechanisms and potential effects; however, their presence does not guarantee an immediate effect on energy or performance.

What are the main risks?

Since caffeine is often the main stimulant in these products, it is a major cause of side effects. In excessive amounts, it can cause:

• nervousness, anxiety, or tremors;
• palpitations or a rapid heartbeat;
• nausea or digestive discomfort;
• difficulty sleeping.

Some people are more sensitive to these effects, particularly those with high blood pressure, cardiovascular disease, or anxiety; pregnant or breastfeeding women; people under 18; and those taking certain medications, including some ADHD medications.

If you have any questions, don’t hesitate to consult a nutritionist or another healthcare professional!

So, is it safe to consume caffeine?

For most healthy adults, moderate caffeine intake is generally considered safe*. However, it’s important to consider all sources consumed throughout the day: coffee, tea, soft drinks, energy drinks, pre-workout supplements, and other supplements.

Although caffeine is one of the few supplements with well-documented effects on performance, its benefits vary depending on the dose, the type of exercise, and individual sensitivity. Good sleep, a balanced diet, and proper hydration remain the best foundations for maintaining energy and promoting recovery.

*Health Canada recommends that healthy adults consume no more than 400 mg of caffeine per day from all sources combined.

Sources:

• Australian Institute of Sport. (n.d.). Caffeine. Australian Sports Commission. Consulted  20 August 2026.
• European Food Safety Authority. (2015). Scientific opinion on the safety of caffeine. EFSA Journal, 13(5), Article 4102.
• Guest, N. S., VanDusseldorp, T. A., Nelson, M. T., Grgic, J., Schoenfeld, B. J., Jenkins, N. D. M., Arent, S. M., Antonio, J., Stout, J. R., Trexler, E. T., Smith-Ryan, A. E., Goldstein, E. R., Kalman, D. S. & Campbell, B. I. (2021). International society of sports nutrition position stand: Caffeine and exercise performance. Journal of the International Society of Sports Nutrition, 18(1), Article 1.
• Health Canada. (2010, 17 mars).Caffeine in Foods – Canada.ca Gouvernement of Canada.

Is there a dark side to energy drinks? is a post from Nautilus Plus. The Nautilus Plus blog aims to help people in their journey to fitness through articles on training, nutrition, motivation, exercise and healthy recipes.
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