We've all been there.

You're pumped up for your workout, you've taken your pre-workout supplement, and then suddenly, you're hit with an unexpected bout of diarrhea.

It's not only inconvenient, but it can also disrupt your workout routine.

But why does this happen?

Can pre-workout really cause diarrhea?

Let's dive into the details.

Pre-workout supplements are designed to help you maximize your workout.

They can provide an energy boost, improve focus, and enhance endurance. [1]

However, like any supplement, they can also have side effects, one of which can be diarrhea.

(See: Can creatine make you poop?)

While it's not a universal side effect, some people do experience diarrhea after taking pre-workout supplements.

This can be due to a variety of factors, including the specific ingredients in the supplement, how those ingredients interact with your body, and even the timing of when you take the supplement.

Although pooping from pre-workouts is common due to the caffeine content, diarrhea may depend on the pre-workout itself.

Caffeine is a common ingredient in many pre-workout supplements. [2]

It's a stimulant that can increase bowel motility, which means it can speed up the time it takes for food to travel through your digestive system.

This can potentially lead to diarrhea.

Caffeine is also found in coffee, but it’s typically dosed much higher in pre-workouts.

Sugar alcohols are a type of carbohydrate that your body cannot fully absorb.

When they reach your large intestine, they can cause water to be drawn into the intestine, which can lead to diarrhea.

Some pre-workout supplements contain artificial sweeteners like sorbitol and xylitol.

Like sugar alcohols, these sweeteners can also cause water to be drawn into the intestine, leading to diarrhea.

It’s possible to find pre-workouts without artificial sweeteners. 

Dehydration is a common side effect of pre-workout supplements because they often contain diuretics like caffeine and green tea extract.

These ingredients can cause you to lose more fluid than you take in, which can lead to dehydration and diarrhea.

Vitamin C is a water-soluble vitamin that acts as an antioxidant. [3]

It can also help to increase bowel motility.

High doses of vitamin C (1000 mg or more) can cause diarrhea in some people.

Creatine is a popular ingredient in pre-workout supplements. [4]

It has been shown to increase muscle mass and strength, but it can also cause gastrointestinal problems like diarrhea, nausea, and cramping.

The ingredients in pre-workout supplements can interact with your digestive system in ways that lead to diarrhea. [5]

For example, caffeine and diuretics can speed up digestion, while sugar alcohols and artificial sweeteners can draw water into your intestines.

This can result in loose, watery stools.

Scientific studies have shown a link between certain ingredients in pre-workout supplements and diarrhea.

For instance, a study published in the American Journal of Gastroenterology found that caffeine can stimulate the colon and speed up transit time in the intestines, leading to diarrhea. [6]

Similarly, a study in the European Journal of Clinical Nutrition found that sugar alcohols can cause diarrhea when consumed in large amounts. [7]

With these steps, you can prevent diarrhea from happening in the first place so your workout doesn’t get ruined.

Drinking plenty of fluids can help keep your digestive system running smoothly and prevent dehydration, which can lead to diarrhea.

Eating a balanced diet can help maintain a healthy digestive system. Avoid foods that can irritate your stomach or intestines.

If you're sensitive to caffeine, consider choosing a pre-workout supplement with lower caffeine content or none at all.

If pre-workout supplements are causing you digestive distress, you might want to consider some alternatives.

Natural energy boosters like bananas, oats, and beetroot juice can provide a pre-workout boost without unwanted side effects.

If you're experiencing persistent diarrhea after taking pre-workout supplements, it's important to consult a healthcare professional.

Persistent diarrhea can lead to dehydration and other serious health issues.

Pre-workout diarrhea can last anywhere from a few hours to a few days.

If your diarrhea doesn’t get better after this time, it is highly recommended to see a doctor.

Some of the common side effects of taking pre-workout supplements are insomnia, diarrhea, headaches, dehydration, high blood pressure, and tingling sensations.

Yes, pre-workout supplements are known to cause stomach problems like diarrhea, bloating, nausea, and even abdominal pain.

Yes, natural energy boosters like bananas, oats, and beetroot juice can provide a pre-workout boost without the unwanted side effects.

If you're experiencing persistent diarrhea after taking pre-workout supplements, it's important to consult a healthcare professional.

Persistent diarrhea can lead to dehydration and other serious health issues.

While pre-workout supplements can be a great tool to enhance your workout, they can also cause side effects like diarrhea in some people.

By understanding the potential causes and how to prevent them, you can make informed decisions about your pre-workout routine.