Does Pre-Workout Make You Poop? Reasons & Prevention

If you are experiencing digestive upset after taking pre-workout, you may be asking yourself: does pre-workout make you poop, or is mine expired?

Yes, pre-workout can make you poop due to caffeine and artificial sweeteners. If your supplement has magnesium, taking too much can also cause diarrhea. To prevent these issues, take your pre-workout with lots of water, and use a supplement without caffeine or artificial sweeteners.

Keep reading to learn more in-depth about:

  • What are the most common ingredients in pre-workout?
  • Does pre-workout make you poop, and why?
  • How to prevent digestive upset after pre-workout?

Buckle up and let's get started.

Common ingredients in pre-workout

Man making himself a pre-workout drink

Before you can better understand why pre-workout makes you poop, let's lay the groundwork.

We do that by presenting some common ingredients found in this supplement, so that we can further discuss them in the context of bowel movement.

Knowing this information will help you choose a supplement which won't have you running for the bathroom after a set of heavy squats. Now, let's see those ingredients.

  • Caffeine. One serving of pre-workout usually contains 100-300mg of caffeine, which is the equivalent of 1-3 coffees. This ingredient has the role of giving you an energy boost for your workout.
  • L-Citrulline. This ingredient is a non-essential amino acid (meaning that your body produces it on its own) which helps with production of nitric oxide. The nitric oxide then expands the blood vessels, leading to better blood flow to the muscles.
  • Vitamin B complex. If you take pre-workout containing B vitamins, you may get an increase in energy and a reduction in fatigue, according to a 2012 study.
  • Beta-Alanine. Yet another non-essential amino acid, Beta-Alanine decreases the lactic acid accumulation in your muscles, reducing fatigue levels during your workouts. And in case you were wondering why pre-workout makes you itchy, this ingredient is the culprit.
  • Artificial sweeteners. Most manufacturers use artificial sweeteners to make the pre-workout tasty while also keeping calories at bay.

Now, given the context of the article, I think you can expect all of these ingredients to lead to a trip to the bathroom. And you are right.

In the following lines, let's explore how these ingredients can upset your stomach.

Does pre-workout make you poop, and why?

dose pre-workout make you poop

Yes, pre-workout does make you poop. There are multiple ingredients which can lead to the same outcome but the most common are caffeine and artificial sweeteners. Aside from the ingredients, drinking your pre-workout with too little water can cause digestive upset due to its concentration.

Now, let's go a bit more in-depth and see how each of the above mentioned ingredients can have laxative effects in their own rights.


This one should come as no surprise.

Most people get the urge to use the bathroom after a cup of coffee.

According to several studies, caffeine stimulates contractions in your intestinal muscles and colon, which help push the contents of your colon towards the rectum. Couple that with physical activity, and you are almost sure to have to poop once your pre-workout kicks in.

If you are sensitive to caffeine in that regard, it may be disheartening to hear that most of the best pre-workouts on the market use caffeine as an ingredient.


L-Citrulline doesn't have any laxative effect.

However, it can still contribute to an unwanted trip to the bathroom. By relaxing and improving your blood vessels' ability to widen, it helps your body get rid of urea - a major component of urine.

So even though L-citrulline in your pre-workout won't make you poop, it may still make you take a trip or two to the bathroom during your training session.

Vitamin B complex

Similar to caffeine, B vitamin stimulates muscle contractions in the digestive system, which then promotes bowel movement.

Unfortunately, B vitamins are being used abusively in pre-workouts.

Supplement companies caught onto the fact that customers associate the tingling sensation after taking pre-workout with its actual effectiveness and potency. That is why, some pre-workouts have vitamin B12 in quantities over 8000% (that's not a typo) your daily recommended intake.

The supplement in question is Pre-Kaged Pre-Workout.

With such quantities of B vitamins, I think we can easily close the case on whether pre-workout makes you poop. But let's keep going with the remaining two ingredients.


This one is tricky. The Beta-Alanine in your pre-workout can cause diarrhea but only if it is in excess quantities. Your body has a self-regulating ability as far as Beta-Alanine is concerned, and it will remove excess levels.

That being said, chances of ingesting too much Beta-Alanine from your supplement are low.

This ingredient is medium to expensively priced, so supplement manufacturers usually don't go overboard with it.

Artificial sweeteners

Most supplement companies use artificial sweeteners to provide a tasty product which is also calorie-free. However, this comes with its own set of drawbacks.

Some people may not be able to digest certain sugar substitutes (artificial sweeteners), which may lead to diarrhea. If your pre-workout doesn't have caffeine or obnoxious amounts of B vitamins or Beta-Alanine but you still have to go to the bathroom after ingesting it, then artificial sweeteners may be the culprit.

How to prevent digestive upset after taking pre-workout?

Picture of woman sitting at the restroom

In this part of the article, we will explore some ways to prevent an unwanted trip to the bathroom after you take pre-workout.

  • Avoid the above mentioned ingredients. This is self-explanatory but if you don't want to poop from pre-workout, then you should avoid as many of the above ingredients as possible. Opt for stim-free supplements instead of those filled with stomach-upsetting ingredients.
  • Don't make your pre-workout too concentrated. If your drink is too concentrated, your body may reject it through diarrhea. Have your pre-workout with plenty of water to prevent this issue from arising.
  • Consider not taking pre-workout. As much as most gym bros don't like to hear this, there are hardly any studies showing pre-workout to be as effective as manufacturers claim. The truth is that it may all just be placebo in the end. Some of the ingredients are effective on their own (while others aren't effective at all) but there is no proof you get better performance by mixing all of them together.

These are the only ways we found to prevent pre-workout from making you poop.

Now obviously, some people are more sensitive than others. You may be among the lucky ones who don't get the urge to run to the bathroom after drinking their supplement.


Now that you know the answer to whether pre-workout makes you poop, let's have a look at some other related questions that people ask.

Does pre-workout give you diarrhea?

Yes, this supplement can give you diarrhea if it has too much Beta-Alanine or artificial sweeteners that your body can't properly digest.

However, this issue is highly dependent on these two ingredients.

Why do workouts make you poop?

When you are working out, due to the acceleration in your breathing and heart rate, you are stimulating the muscles of your intestines.

These muscles are responsible for bowel movements so you will eventually get the urge to go to the bathroom.


So, does pre-workout make you poop?

Yes, it can, if it has caffeine, ridiculous amounts of B vitamins or Beta-Alanine, or if they are sweetened with artificial sweeteners. However, it all depends on your body and the strength of your digestive system.

Personally, I don't get the urge to go to the bathroom at any point after drinking my supplement. Some of my friends, on the other hand, do.

If you are among the unlucky ones, choose a supplement that won't have the ingredients presented above and you should be fine.

Over to you.