What organ is most affected by energy drinks?

When you down an energy drink, you’re not just getting a quick buzz-you’re flooding your body with a potent mix of caffeine, sugar, and stimulants. But while you might feel energized, your body is working overtime to handle the load. One organ takes the biggest hit: your heart.

The heart bears the brunt

Energy drinks spike your heart rate and blood pressure within minutes. A 2022 study published in the Journal of the American Heart Association found that just one 16-ounce energy drink increased systolic blood pressure by an average of 6.8 mm Hg and heart rate by 12 beats per minute in healthy adults. That’s the same as running a short sprint. For someone with underlying heart conditions, this can trigger arrhythmias, palpitations, or even heart attacks.

Why? Caffeine blocks adenosine, a chemical that normally slows your heart. At the same time, the sugar and other stimulants like taurine and guarana trigger adrenaline release. Your heart doesn’t know if you’re running from a bear or just scrolling on your phone-it just pumps harder. And when you’re drinking these daily, that constant stress wears down the muscle over time.

The liver doesn’t get a break

Your liver is the body’s detox center. When you consume energy drinks, it’s the first organ to process the flood of caffeine, artificial sweeteners, and sugar. A single can can contain up to 54 grams of sugar-that’s nearly 14 teaspoons. Your liver turns that sugar into fat, especially when it’s already overloaded from processed foods.

Over time, this leads to non-alcoholic fatty liver disease (NAFLD). A 2023 analysis from the University of Sydney tracked 1,200 young adults who consumed energy drinks at least three times a week. Nearly 40% showed early signs of liver fat buildup-even if they weren’t overweight. That’s alarming because NAFLD often has no symptoms until it’s advanced. And unlike alcohol-related liver damage, this one creeps up silently, fueled by the same drinks marketed as “energy boosters.”

Other organs in the crosshairs

Your kidneys aren’t safe either. Caffeine is a diuretic, which means it pulls water out of your body. When you’re chugging energy drinks and not drinking enough water, your kidneys have to work harder to filter out the toxins. Chronic dehydration from these drinks can lead to kidney stones or even acute kidney injury in extreme cases.

Then there’s your brain. High doses of caffeine can disrupt sleep patterns, increase anxiety, and even cause headaches or seizures in sensitive individuals. Teens and young adults are especially vulnerable-their brains are still developing, and caffeine alters dopamine signaling in ways that may increase dependency.

And let’s not forget your stomach. The acidity in energy drinks (often lower than soda, but still high) can irritate the stomach lining. People who drink them regularly report nausea, acid reflux, and even ulcers. One 19-year-old college student in Brisbane ended up in the ER with a bleeding ulcer after drinking three energy drinks a day for six months. His doctors said it wasn’t stress-it was the drinks.

What’s really in these drinks?

Most people don’t realize how little regulation there is. In Australia, energy drinks don’t need to list the total caffeine content if it’s under 320mg per liter. But many brands push that limit. A 500ml can of some popular brands contains 160mg of caffeine-equivalent to two strong coffees-plus another 40mg from guarana, which isn’t always counted. That’s 200mg in one drink. The FDA recommends no more than 400mg of caffeine per day for adults. One drink can take you halfway there.

Sugar isn’t the only hidden problem. Ingredients like inositol, L-carnitine, and B-vitamins sound healthy, but they’re added in amounts too low to help and too high to be safe in combination. The real danger isn’t any single ingredient-it’s the cocktail.

Who’s most at risk?

Teens and young adults are the biggest consumers. A 2024 survey in Queensland found that 68% of high school students had consumed an energy drink in the past month. Athletes think they need them for performance-but studies show they don’t improve endurance. In fact, they can cause cramping and dehydration during exercise.

People with anxiety, heart conditions, or sleep disorders should avoid them entirely. Even healthy people aren’t immune. The American Heart Association warns that energy drinks are not safe for children, pregnant women, or those with caffeine sensitivity.

What should you do instead?

If you’re tired, your body isn’t asking for caffeine-it’s asking for sleep, water, or movement. A 10-minute walk, a glass of water, or a short nap will do more for your energy than any drink. If you need a boost, try:

• Green tea (natural caffeine + L-theanine for calm focus)
• Electrolyte drinks with no sugar or artificial sweeteners
• Black coffee (no added sugar, limit to one cup)
• Hydration with a pinch of sea salt and lemon

These options give you steady energy without the crash or the organ damage.

Bottom line

The heart takes the hardest hit from energy drinks-but the liver, kidneys, brain, and stomach aren’t far behind. There’s no such thing as a “safe” energy drink if you’re drinking them regularly. They’re not sports nutrition. They’re not health products. They’re stimulant cocktails designed to get you hooked.

If you’re drinking them to stay awake, push through a workout, or chase a mood boost-you’re trading short-term energy for long-term damage. Your organs don’t get a day off. Neither should your caution.