Does pre-workout make you poop?” 

This may seem like a silly question, but it’s one many people ponder.

Why do you feel the need to use the bathroom after taking pre-workout?

What other factors contribute to pre-workout-induced pooping?

And how can you choose a pre-workout that boosts your performance without making you rush to the restroom?

Get evidence-based answers to these questions and more in this article. 

What Is A Pre-Workout?

A “pre-workout” is a sports nutrition supplement taken before training to enhance energy levels and exercise performance.

They usually contain a mix of ingredients, such as caffeine, citrulline malate, and beta-alanine.

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Why Do Pre-Workouts Make You Poop?

Many pre-workout powders contain ingredients that interact with your digestive system and stimulate bowel movements.

Common pre-workout ingredients with this side effect are sodium bicarbonate, vitamin C, magnesium, caffeine, and artificial sweeteners


Caffeine is probably the most common pre-workout ingredient. In some cases, supplements contain as much as 600 mg of caffeine (more than 6 times the caffeine content of a cup of caffeinated coffee)

Caffeine is a pre-workout mainstay because it boosts athletic performance by improving strength, promoting muscle endurance, and enhancing anaerobic performance. However, it also impacts your digestive system. 

Specifically, caffeine stimulates colonic motor activity—the process of moving your gut’s contents through the digestive tract. In other words, it gets your colon rollin’.

Artificial Sweeteners

Many pre-workout supplements contain large amounts of artificial sweeteners. 

Studies show that consuming large quantities of these sweeteners can cause digestive issues and laxative effects, particularly for those with sensitive stomachs.


Magnesium plays a crucial role in muscle function and energy metabolism and is, therefore, a common ingredient in pre-workout formulas.

Beware though, high doses can draw water into your intestines, speeding up digestion and potentially leading to untimely restroom trips.

Vitamin C

Supplement companies sometimes include vitamin C in pre-workout powders as a flavoring and to potentially accelerate post-exercise recovery by reducing inflammation (which may also blunt some of exercise’s positive effects).

The downside is that taking large doses can upset your stomach.

That said, most pre-workouts don’t contain enough vitamin C to cause this effect alone. Thus, it’s only a concern if you also consume a diet rich in vitamin C. 

Sodium Bicarbonate

Some people take sodium bicarbonate (baking soda) as a “homemade” pre-workout because it may boost athletic performance.

However, baking soda also causes a buildup of CO2 in the stomach, which commonly causes diarrhea.

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Other Factors that Contribute to Pre-Workout Pooping


The timing of your pre-workout intake greatly influences its effect on your digestion.

For instance, if you consume pre-workout in the morning when your stomach is empty, your body will absorb the ingredients rapidly. This may increase the odds you’ll need to use the bathroom. 

If you take pre-workout before an afternoon or evening workout, you’re less likely to experience digestive issues. That’s because the food you’ve eaten throughout the day prevents your body from absorbing the pre-workout as quickly.


Ingredients like caffeine and artificial sweeteners have a “dose-dependent impact” on your body. 

In other words, the more you consume, the higher your chances of experiencing side effects.

Therefore, finding products that include doses that maximize benefits without leading to unwanted effects is key.

Stomach Contents

The contents of your stomach can also influence how pre-workout affects your digestive system.

For instance, taking your supplement with food can slow digestion, potentially reducing any laxative effect. 

On the other hand, taking pre-workout powder on an empty stomach can worsen its side effects.

How to Choose A Pre-Workout That Won’t Make You Poop

Stim-Free Pre-Workout

Of all the ingredients above, caffeine is the most likely to cause stomach upset and bowel movements.

Therefore, using a pre-workout that doesn’t contain caffeine can effectively prevent pre-workout-induced pooping.

That’s where “stim-free” pre-workouts come in.

Stim-free pre-workouts are supplements that contain no stimulatory ingredients (e.g. caffeine) but still improve your athletic performance. 

This makes them a suitable alternative for those experiencing digestive issues with regular pre-workout powders.

Natural Sweeteners and Flavors

Opting for pre-workout powders that contain natural sweeteners and flavors can help minimize digestive upset.

Generally, natural options are more digestible, potentially leading to fewer stomach problems than artificial alternatives.

Clinically Effective Doses

Many people wrongly assume that when it comes to pre-workout ingredients, higher doses are better. 

This is a misconception—most pre-workout ingredients only boost performance up to a certain point. 

Taking more than this doesn’t improve your performance further, but it can increase your risk of experiencing unwanted side effects.

Unfortunately, some supplement companies capitalize on the “more is better” mindset by including excessive doses of stimulants in their products. This makes their products appear more potent, even though they’re actually less effective (and potentially dangerous).

To avoid this trap, look for products containing clinically effective doses of each ingredient. 

This means they include each ingredient at a level that confers the maximum benefits with the minimum side effects. 

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The Best Pre-Workout

If you want a 100% naturally flavored and sweetened pre-workout supplement containing clinically effective doses of 6 performance-boosting ingredients like caffeine, citrulline malate, and beta-alanine, try Legion’s pre-workout powder, Pulse

Or, if you’d prefer a 100% natural and stimulant-free pre-workout drink that boosts strength and stamina while reducing fatigue, try stim-free Pulse

(If you’re uncertain whether Pulse suits your needs and budget, take the Legion Supplement Finder Quiz to learn what supplements are right for you. Click here to check it out.)


Choosing the right pre-workout supplement can significantly improve your athletic performance and energy levels. 

However, it’s crucial to understand the impact ingredients like caffeine and artificial sweeteners have on your digestive system.

To minimize stomach upset, choose a pre-workout containing clinically effective doses of every ingredient. And if you still experience unexpected bowel movements soon after taking your pre-workout, opt for a stim-free version instead. 

+ Scientific References