Can Protein Powder Cause Constipation?

📌 Overview and Key Takeaways

Can protein powder cause constipation?

Discover what causes protein powder constipation and how to avoid this common side effect.

Last Updated
Jan 8, 2026

Author and Medical Reviewer

Written by Jack, CNC

Jack is a National Academy of Sports Medicine Certified Nutrition Coach.

Medically reviewed by Brittany, MS, RD and Jenn, PA-C

Brittany is a Registered Dietitian with a MS in Nutrition.

Jenn is a Physician Assistant with a BA in Nutritional Sciences.

Protein Powder Constipation

Does Protein Powder Cause Constipation?

Yes, protein powder can cause constipation.

Although a common side effect of protein supplements is diarrhea, many people report that protein shakes and powders also make them constipated.

Constipation occurs when you have fewer than three bowel movements a week and your poop is hard and difficult to pass.

Common symptoms include bloating, nausea, and stomach pain.

Note that although constipation usually does away on its own, it never hurts to seek medical advice.

Why Does Protein Powder Cause Constipation?

In most cases, protein powder constipation has nothing to do with the type or amount of protein in your protein powder.

Instead, protein powders make you constipated because they contain added ingredients that are hard to digest.

Here are some of the top protein powder ingredients that can make you constipated:

Food Additives

Emulsifiers, thickeners, and other ultra-processed additives look nothing like real food, which makes them hard to digest.

As a result, they feed your gut bacteria, which release gas as they eat.

And too much intestinal gas can cause bloating and constipation!

Regularly eating certain food additives can also alter the composition and function of your gut microbiome (North Clin Istanb, 2019).

These shifts, known as gut dysbiosis, contribute to constipation through multiple mechanisms (Appl Microbiol Biotechnol, 2022).

Specifically, dysbiosis alters production of key metabolites including short-chain fatty acids (SCFAs), bile acids, and tryptophan metabolites that regulate intestinal motility and secretion.

⚠️ Here is a list of the most common food additives in protein supplements:

• acacia fiber
• acacia gum
• acesulfame potassium
• artificial flavors
• ascorbic acid
• aspartame
• calcium carbonate
• carrageenan
• cellulose gum
• dextrin
• dicalcium phosphate
• dipotassium phosphate
• erythritol
• gellan gum
• guar gum
• gum arabic
• inulin
• locust bean gum
• maltitol
• maltodextrin
• mono- and diglycerides
• ‘natural’ flavors
• rice bran extract
• rice dextrin
• rice hulls
• rosemary extract
• silica
• silicon dioxide
• sodium alginate
• soluble corn fiber
• sorbitol
• soy lecithin
• sucralose
• sunflower lecithin
• tocopherols
• tricalcium phosphate
• xanthan gum
• xylitol
• zinc oxide

As a rule of thumb, if you cannot find it in nature or make it at home, it is probably a food additive.

🚫 Avoid Dairy-Based Proteins

Dairy-based proteins like whey and casein, although not an issue for everyone, can cause side effects like constipation too.

This is usually because they contain lactose, a sugar many individuals with sensitive stomachs cannot fully digest.

But you might be sensitive to dairy-based proteins even if you are not lactose intolerant.

This is particularly true for casein protein, which forms a gel-like substance in your stomach that slows down digestion.

🚫 Avoid Protein Concentrates and Isolates

If you have a sensitive stomach, you might also want to avoid ultra-processed protein concentrates and isolates.

Most protein supplements are made from one or both of these ultra-processed protein sources, which have been mechanically and/or chemically stripped of everything but the protein.

This includes the enzymes, fiber, and other natural digestive aids that help your gut break them down.

You therefore do not digest them in the same way that you do whole foods, which could affect your gut health.

Studies show that regularly eating protein concentrates and isolates might disrupt your gut microbiome (Nutrients, 2018) and cause the formation of toxic byproducts in your gut (Mol Nutr Food Res, 2024).

Individuals with pre-existing digestive issues should thus look for protein supplements made from whole food protein sources like egg whites and almonds, which are easier to digest and absorb.

Order Samples to see for yourself.

What Should I Do if Protein Powder Makes Me Constipated?

If you are constipated and looking for relief, try the following remedies.

Just keep in mind that everyone is different and that what works for someone else might not necessarily work for you.

Remember to be patient too, as most of these remedies take 12 to 72 hours to work.

1. Drink water. Drinking lots of water, especially warm or hot water in the morning, softens your stools.
2. Exercise. Movement can stimulate the muscles in your colon.
3. Eat fiber. Fiber increases the size of your stool, helping it move through your digestive tract. It also softens your stool, making it easier to pass.
4. Drink coffee. Caffeine can stimulate involuntary muscle contractions in your colon.
5. Use a laxative. If all else fails, try a laxative. Most laxatives can be purchased over-the-counter. I put laxative last on the list because laxatives have potential side effects, such as allergic reactions and vitamin deficiencies.

Occasional constipation is nothing to worry about, but if protein powders regularly make you constipated, it is probably time to switch brands.

If you are not ready to switch, however, here are some steps you can take to reduce or perhaps avoid symptoms:

Sources

1. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2019.
2. Applied microbiology and biotechnology (Appl Microbiol Biotechnol). Gut microbiota: a new avenue to reveal pathological mechanisms of constipation.. 2022.
3. Nutrients (Nutrients). Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study. 2018.
4. Molecular nutrition & food research (Mol Nutr Food Res). In Vitro Fermentation of Animal and Plant Protein Isolates by the Human Gut Microbiota Under High and Low Carbohydrate Conditions.. 2024.

Editorial Guidelines

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This article was written by a Registered Dietitian and reviewed by a Physician Assistant. We rely on peer-reviewed research and trusted medical sources, and regularly update our content to ensure accuracy and clarity.