Whey Protein Powder and IBS
Digestive HealthIBS

Does Whey Protein Powder Worsen IBS?

Does Whey Protein Powder Worsen IBS?
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Updated on October 27, 2025
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Protein is a vital nutrient, and it plays an important role in muscle growth and tissue repair when you exercise.

 Over the years, protein shakes have become popular for post-workout refueling and weight loss.

Protein shakes and powders include a wide range of products, including some that are terrible for your gut and others that are fine, says Elena Ivanina, DO, an integrative gastroenterologist in New York City. But most protein shakes and powders should be avoided by people with irritable bowel syndrome (IBS), Dr. Ivanina says.

IBS is a condition involving a group of symptoms, including abdominal pain and changes in bowel movements, such as diarrhea or constipation.

 Protein powders and shakes with whey, a protein derived from milk, can trigger IBS symptoms. Some may also contain artificial sweeteners and added sugar, which may also cause symptoms.

Why Protein Shakes With Whey Can Trigger IBS

Whey protein powder is a powdered collection of proteins derived from whey, which is the liquid that remains after cheese is made from cow’s milk.

 It should not be consumed by people with IBS, according to Ivanina.

Various foods affect people with IBS differently, but milk and other dairy products often cause gas and bloating. “Looking at one whey protein complex powder, the ingredients include multiple milk-based items and lecithin, which is an emulsifier,” she says. These ingredients can trigger IBS symptoms and gut inflammation.

Certain sweeteners that may be added to protein shakes, such as sugar alcohols like sorbitol, have also been found to cause gastrointestinal distress in people with IBS.

If you find that protein shakes, especially those with whey protein, trigger your IBS symptoms, get your daily dose of protein from whole-food sources instead. Fish, poultry, eggs, nuts, and seeds can be good options for those eating an IBS diet.

Protein Shakes: What’s in Them and What’s Not

“Protein powders,” Ivanina says, “may include added sugars, unnecessary calories, artificial colors and flavoring, emulsifiers and thickeners, and excessive vitamins and minerals that may impact gut health and symptoms.”

Protein shakes also don’t have the same amount of dietary fiber, antioxidants, and other important substances as you’ll find in protein-rich whole foods.

 Most people get enough protein (often too much) from the foods they eat, so protein supplements like shakes are often unnecessary in the first place.

Ivanina also points out that a nonprofit group called the Clean Label Project studies toxins in protein powders. Its latest report found that many protein powders contain heavy metals like lead, arsenic, cadmium, and mercury.

“While there may be some wholesome and natural protein shake options,” Ivanina says, “the general caution is beware of powders and blends that contain many ingredients and instead stick to wholesome natural foods if you have irritable bowel syndrome.”

What About Meal Replacement Shakes?

Meal replacement shakes have been promoted for people with IBS because they’re easy to digest, but Ivanina says they should also be avoided.

“At this time there is no convincing data supporting [the idea] that meal replacement shakes are good for people with IBS,” she says. “The best management of IBS includes an integrative approach with a gastroenterologist, nutritionist, and therapist to cover the food triggers as well as the gut-brain axis that is so vital to address in IBS.”

The Takeaway

  • People with irritable bowel syndrome should avoid whey protein powder because it poses risks for gut irritation. Other protein shakes can contain ingredients like emulsifiers and certain sweeteners that may also exacerbate IBS symptoms.
  • People with IBS may be better off obtaining their protein from whole foods, such as fish, poultry, eggs, nuts, and seeds.
  • For effective IBS management, a holistic approach involving guidance from a gastroenterologist, nutritionist, and therapist can help you address dietary triggers and the gut-brain connection that is crucial to IBS care.
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Waseem-Ahmed-bio

Waseem Ahmed, MD

Medical Reviewer

Waseem Ahmed, MD, is an assistant professor of medicine in the Karsh Division of Gastroenterology and Hepatology at Cedars-Sinai Medical Center in Los Angeles and serves as Director, Advanced Inflammatory Bowel Disease Fellowship and Education within the F. Widjaja Inflammatory Bowel Disease Institute.

He received his undergraduate degree from the University of Michigan and attended medical school at Indiana University. He then completed an internal medicine residency at New York University, followed by a fellowship in gastroenterology and hepatology at Indiana University, and an advanced fellowship in inflammatory bowel disease at the Jill Roberts Center for Inflammatory Bowel Disease at New York-Presbyterian Hospital/Weill Cornell Medicine. Prior to his current role, Dr. Ahmed served as an assistant professor of medicine within the Crohn’s and Colitis Center at the University of Colorado from 2021-2024.

Dr. Ahmed is passionate about providing innovative, comprehensive, and compassionate care for all patients with inflammatory bowel disease (IBD). His research interests include IBD medical education for patients, providers, and trainees; clinical trials; acute severe ulcerative colitis; and the use of combined advanced targeted therapy in high-risk IBD.

He enjoys spending time with his wife and dog, is an avid follower of professional tennis, and enjoys fine dining.

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William Payton

Author

William Payton is an experienced healthcare writer and editor specializing in consumer-targeted health information and medical content creation. He has contributed articles to multiple health and medical publications, including Livestrong.com, Lose It!, and Plastic Surgery Practice magazine. His work focuses on making complex medical concepts accessible to general audiences while maintaining accuracy and evidence-based reporting.

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Resources
  1. Nutrition and Athletic Performance. MedlinePlus. April 1, 2025.
  2. When You Should Drink a Protein Shake. Cleveland Clinic. October 22, 2022.
  3. Irritable Bowel Syndrome (IBS). Johns Hopkins Medicine.
  4. Is Whey Protein Good for You? Cleveland Clinic. January 4, 2021.
  5. Fernández-Bañares F. Carbohydrate Maldigestion and Intolerance. Nutrients. May 4, 2022.
  6. The Hidden Dangers of Protein Powders. Harvard Health Publishing. August 15, 2022.
  7. Protein Study 2.0. Clean Label Project.