close up photo of woman touching her abdomen

Why Does Pre Workout Make You Poop? [and How To Avoid It 💩]

Pre workout has become the staple of any serious gym-goer. The market for pre workouts alone is worth over $13 billion, and it’s expected to reach $23.8 billion by 2027.

A pre workout drink before a vigorous training session can help bust through plateaus, increase your focus, and even direct blood to your muscles, helping to create that full pumped look.

All this is well and good, but what if your pre workout leaves you running to poop after you’ve taken it? Feeling like Superman with laser focus is no good if you’re stuck on the toilet. 

Pre workout can have adverse side effects on some people, and one of them is that your favorite pre workout supplement might be making you poop. In this article, we’ll investigate how your pre workout might be forcing you to spend your workout in the restroom and if there’s anything you can do about it.

Does Pre Workout Make You Poop?

The quick answer to this question is “yes and no.” We’ve all heard about pre workouts making you itch, but there are a few ingredients that you’ll find in most pre workout supplements that can play havoc with your bowels. But that doesn’t mean that everyone who takes pre workout is going to be spending their precious training time sitting on the loo.

One of the most enriching qualities of the human race is that we’re all different, and this goes for bodybuilders, too. Just because one ingredient is your pre workout can cause you to poop, doesn’t mean it will disrupt everyone.

Let’s take a closer look at some of the ingredients that might be making you poop.


If you’re using a stimulant-based pre workout and it’s making you poop, then the chances are the guilty party is caffeine. Caffeine is a stimulant and so it wakes you up. This includes your digestive system. 

Caffeine causes muscular contractions in the colon and intestinal muscles. It has been found to make the colon 60% more active than water does. Also, keep in mind that the average cup of coffee contains about 100 mg of caffeine. Your pre workout supplement probably contains between 250-400 mg!

If caffeine is your problem, then you can try a non-stimulant pre workout that still contains ingredients to increase your focus. If you’re not ready to say goodbye to the caffeine kick, then you can try reducing the size of your pre workout serving and gradually increase it as your body builds up a tolerance.   

Amino Acids

While not many pre workout supplements contain amino acids, you might find that yours does. Amino acids are sometimes included to stop your body from breaking down muscle tissue for energy if you train fasted.

Of the amino acids, the two biggest culprits that might be in your pre workout supplement are citrulline and cystine. These have been known to cause several gastrointestinal side effects, including diarrhea and abdominal cramping.

Amino acids aren’t a necessity when it comes to fueling your training, so if you think they might be responsible for your need to poop, then just find a pre workout supplement that doesn’t contain them. 


Yohimbe is often used in non-stimulant pre-workouts as it can increase energy and focus without the jittery side effects of caffeine. It’s quite common in pump-based pre workout drinks.

Unfortunately, Yohimbe is known to upset sensitive stomachs, especially if you’re training on an empty stomach. Taking a pre workout supplement that contains Yohimbe a couple of hours after a meal can help reduce stomach sensitivity.  

Artificial Sweeteners

One thing that most people notice when they first try a pre workout drink is the explosion of flavor. Some of them taste great while boasting zero grams of sugar. Well, there’s only one way to get this kind of taste, and that’s with artificial sweeteners. 

Many of the zero-calorie alternatives to sugar don’t absorb well in the gut. This can result in a case of diarrhea for more sensitive users. If you think artificial additives might be causing you toilet problems, then look for a pre workout supplement that boasts all-natural ingredients. 

Vitamin C

Pre workout supplements often contain a large amount of vitamin C because it can aid with recovery during and after your workout. Vitamin C is also known for its laxative effect when taken in large doses. 

If you think that Vitamin C might be responsible for your needing to poop, then find a pre workout that doesn’t contain vitamin C. If you still want to harvest the recovery-boosting properties of Vitamin C, then just add it you your post workout drink.  

Vitamin B12

Vitamin B12 is added to a wide range of pre workout supplements. It helps your body to metabolize fats, proteins, and carbohydrates, giving you more energy during your workout.

However, vitamin B12 can also be used to help treat constipation because it stimulates muscle contraction in the digestive system. There are plenty of other pre workout ingredients that help boost your energy, so if vitamin B12 is making you run to the toilet, then find a pre workout supplement without it.   


Wait, what!? Water is making me poop? Okay, it’s not the most likely of the ingredients in your pre workout, but drinking water is necessary for every function in the human body, including pooping. 

Drinking water, especially first thing in the morning, can kick-start your digestive system. This could be the reason you’re running to the toilet after you take your pre-workout. If it turns out that the culprit is water, then just try using as little water as possible to dilute your pre workout powder.  

Enjoy a Poop-Free Pre Workout

The majority of pre workout supplements contain something that might make you poop. However, if you can identify that one, in particular, is causing you problems, then it’s easy enough to find a pre workout that doesn’t contain it.

You might even find that you can keep your workouts uninterrupted by not taking your pre workout on an empty stomach. You might have to get up a bit earlier in the morning to eat a small snack, but you’ll be grateful for taking the time when you start to enjoy the benefits of a rumble-free workout.

Click here to read more about stimulant-free pre workouts that can get you working out without the urge to crap your pants.