Can protein powder cause diarrhea?

Protein powder can sometimes lead to diarrhea, particularly when consumed in large amounts or if an individual has an underlying sensitivity. The reason for this can vary based on the type of protein powder and individual dietary tolerances. Whey and casein protein powders, which are derived from milk, contain lactose. Lactose intolerance is a common condition that can cause diarrhea and other gastrointestinal symptoms in people who have difficulty digesting lactose (1). Plant-based protein powders, such as those made from peas, hemp, or rice, can also cause digestive issues due to their high fiber content, which can be difficult for some individuals to process (2).

Another factor to consider is the presence of artificial sweeteners in some protein powders. Sweeteners like sorbitol and xylitol can have a laxative effect when consumed in large quantities (3). Additionally, some people might be allergic or sensitive to specific ingredients used in protein powders, which could lead to diarrhea. It's important to monitor how your body reacts to a new protein powder and consult a healthcare provider if you experience adverse effects. Moderation is key, and it may be beneficial to try different types of protein powders to find one that suits your digestive system best.