can pre-workout cause fever?

You’re at the gym, ready to pump some iron. You’ve got your favorite brand of pre-workout supplement in one hand, and a bottle of water in the other. You down your pre-workout, and suddenly you start feeling hot, sweaty, and maybe even flushed.

This is not how you want to feel before working out! But it’s also not uncommon for some brands of pre-workout supplements to cause your body temperature to rise and make you feel feverish.

Pre-Workouts Can Cause Your Body Temperature To rise

While feeling fever-like is not the worst side effect of taking pre-workout supplements, it can be uncomfortable and inconvenient. If your body temperature rises above 101 degrees Fahrenheit (38 degrees Celsius), you should consult with a doctor or seek medical treatment.

Generally, the cause of a fever is normally an immune response to a viral or bacterial infection, but it can also be due to an allergic reaction or some other form of inflammation in the body.

Some pre-workout ingredients can cause your body temperature to rise, make you sweat more, and therefore give you the feeling of a fever.

Caffeine Is Sometimes A Culprit

Caffeine is a stimulant and increases thermogenesis. So it can raise your body temperature slightly as well as your heart rate. This can be enough to feel mildly feverish when accompanied by its other side effects like flushed skin, sweating, and heart palpitations.

caffeine formula

Pre-workout supplements are usually loaded with caffeine as an active ingredient. If you’re taking pre-workouts that contain caffeine, it’s possible that the supplement could be causing your fever rather than your workout itself (though not necessarily).

Citrulline May Make You Feel Hot

Citrulline is a substance that causes the blood vessels to expand to improve blood flow and reduce blood pressure. This vasodilation process should actually reduce your body temperature but can sometimes give the feeling that your body is getting hotter.

It’s important to note that this is not a cause for concern. It’s completely normal for it to cause your body temperature to rise when you take it.


Beta-alanine is an amino acid that can be found in many pre-workout supplements. It’s also naturally occurring in your body and helps with muscular endurance and reduce muscle fatigue during exercise.

supplement scoop

When you take beta-alanine as a supplement, though, it causes an itchy and tingling sensation on the skin. When combined with the other ingredients, it can definitely make you feel like your body is getting feverishly hot.

It’s common for gym-goers to say that beta-alanine causes them to sweat more during a training session. The effects of beta-alanine wear off after around 1 hour.

Thermogenic Ingredients

Supplements with thermogenic extracts such as green tea extract, cayenne pepper, or garcinia cambogia can also increase your body temperature. There is a reason that the types of ingredients are common in fat burners and weight loss supplements.

When your body is at a higher temperature, it has to burn energy to stay warm, which means more calories are being burned and more fat is being used as fuel. This also means that your body will be better able to release energy from fat stores than it would be at a lower temperature.

Don’t Take Too Much Pre-Workout

One of the reasons that I dislike proprietary blends is that they often do not state the amounts of ingredients per serving. So it is difficult to know which ingredients may be causing effects.


When you take too much pre-workout or more than the recommended dose, it is known to cause many side effects. It’s possible for your body temperature to spike higher than normal and could even potentially lead to heat exhaustion if you exercise in a hot environment.

Heat Exhaustion

If you feel very hot then there is a risk of heat exhaustion and you shouldn’t exercise in that state. Heat exhaustion can lead to heatstroke, which is a serious medical emergency. If you experience this, take a break from your workout, drink plenty of water, and rest in a cool place until your body temperature goes down. If the feeling continues to persist after 24 hours, seek medical advice.

Don’t Get A Real Fever!

Bacteria in your pre-workout supplement can give you a fever. To prevent any mold or bacteria growth and prevent the risk of fever:

  • Store it in a cool and dry place.
  • Ensure that the lid is tight
  • Don’t mix it with water unless you will be drinking it within a reasonable time
  • Don’t use it past its expiration date

Don’t let your pre-workout make you ill and be sensible with its storage.

Final Thoughts

If you experience a feeling of fever from your pre-workout supplement, it’s important not to panic. In most cases, the fever will go away on its own when the ingredients wear off and pass through your system.

If you feel ill, the best thing you can do is drink lots of water and take a break from your workout until the symptoms subside. If this doesn’t work or if you’re worried about more serious symptoms then see your doctor immediately!