If you’ve ever taken pre-workout, you know how odd the first time can feel. You might get a tingle, feel jittery, or notice a sudden rush of energy — and your first thought is often, “Is this safe?”
For most people, pre-workout supplements are legal, safe, and don’t cause serious side effects. Using the right dose and picking products without harmful ingredients can help you avoid unpleasant reactions like headaches, stomach problems, or water retention.
In this article, we’ll look at whether pre-workouts are truly safe, what side effects they might cause, and how to reduce those risks.
Pre-workout supplements come in many forms — pills, powders, even candy — and they can contain a wide range of ingredients. Because of that, it’s important to check what’s in the product you choose. Make sure it’s FDA-approved and that all ingredients and their amounts are clearly listed. Pre-workouts are considered dietary supplements, so they should contain only “dietary ingredients” like vitamins, minerals, and herbs that are allowed in supplements.
You shouldn’t find pharmaceutical ingredients in pre-workouts, since they’re not intended to treat or prevent disease. If a supplement contains only dietary ingredients at proper doses, it’s generally safe to take before a workout.
That said, pre-workouts aren’t for everyone. They’re meant for adults only — people under 18 should avoid them. If you have a history of heart problems, cancer, Parkinson’s disease, thyroid issues, or other medical conditions, don’t start a pre-workout without talking to your healthcare provider.
Even if you’re healthy, it’s smart to check with your doctor if you have any doubts. Your health history can affect whether a pre-workout is a good choice for you.
Though many pre-workouts are safe and can boost performance, they can still cause side effects for some people, even when the ingredient list looks clean and the product is FDA-approved. Here are some common issues.
Creatine is a popular pre-workout ingredient. It can improve exercise performance and help increase lean muscle mass, but it often causes temporary water retention. That’s why some people gain weight when they start taking creatine. The effect usually lessens as your body adjusts.
Several pre-workout ingredients can cause digestive problems, including caffeine, magnesium, and sodium bicarbonate. Magnesium and caffeine can have a laxative effect, so it’s not unusual to find yourself using the restroom more often after taking certain pre-workouts. Sodium bicarbonate can also cause this, but usually only at doses higher than 0.3 g per kilogram of body weight, which most pre-workouts don’t contain. Mixing your pre-workout with more water can help, since a very concentrated drink is more likely to cause loose stools.
Caffeine is a strong stimulant and offers real performance benefits, but it also has side effects when taken in excess: insomnia, a faster heart rate, anxiety, and jitters. Some pre-workouts pack a lot of caffeine — up to 500 mg per serving — while a regular cup of coffee has about 95 mg. If caffeine’s side effects bother you, choose a pre-workout with a lower dose or a stimulant-free formula.
Overall, pre-workout supplements can be safe, especially when their ingredients are clear and approved. However, they can cause unpleasant side effects and are generally not recommended for people with heart conditions, anxiety, or other health concerns. Before you start using them, talk to a healthcare professional to make sure they’re right for you.