Yohimbine is a compound found in some pre-workout and fat-burning supplements. While it may be an effective stimulant for weight loss, it can also cause an upset stomach and other adverse effects3.
In my experience, taking yohimbe bark extract on an empty stomach can result in “emergency evacuation.” However, supplements with yohimbine HCl seem to cause fewer adverse effects.
6. Added Sugars
In addition, some pre-workouts contain artificial sweeteners known as sugar alcohols for flavoring. However, these zero-calorie additives don’t absorb well in the gut and can cause diarrhea in some people.
Lastly, unless you’re “dry scooping,” you probably mix your pre-workout powder with water. And drinking a glass of water is a surefire way to get your digestive system moving, especially in the morning.
One way around this is to take your pre-workout with less water. As little as 3 ounces is usually enough to dissolve the powder. Just make sure you drink plenty of water throughout the day!