What Are the Ingredients to Avoid in Protein Powder?

📌 Overview and Key Takeaways

This is a Dietitian’s guide on the ingredients to avoid in protein powder.

Discover the top 3 ingredients to stay away from.

Last Updated
Jan 12, 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.

Ingredients to Avoid in Protein Powder

This is an overview of the top ingredients to avoid in protein powder.

By avoiding these 3 types of ingredients, you can ensure that you are safely supplementing your protein intake.

🚫 Avoid Food Additives

In the United States, food additives are approved for human consumption by the U.S. Food and Drug Administration (FDA), which suggests they are safe.

But many of these same food additives are banned or restricted in other parts of the world, such as the European Union, due to health concerns.

Moreover, more and more research suggests regularly consuming certain approved food additives can cause side effects and even long-term health problems (Nat Rev Gastroenterol Hepatol, 2024).

This should make you think twice before consuming a packaged food, beverage, or supplement without first reading the ingredient list.

A food additive is any ingredient added to a food (or supplement) during its production, processing, packaging, or storage to enhance its flavor, texture, appearance, or shelf life.

Food additives are technically ultra-processed ingredients, meaning they look little to nothing like foods found in nature.

For this reason, they are hard to digest (break down and absorb), which cause painful side effects like bloating and diarrhea.

It can also alter the composition of your gut microbiome (the collection of microorganisms living in your gut), which can lead to gut dysbiosis, or an imbalance in gut bacteria (North Clin Istanb, 2019; Microorganisms, 2022).

Gut dysbiosis, in turn, can contribute to chronic diseases like obesity, type 2 diabetes, and even cancer (Mol Nutr Food Res, 2019).

In short, although more research is needed, the preliminary evidence linking the regular consumption of food additives to side effects and disease is more than concerning.

⚠️ 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

Note that this is not a comprehensive list.

Also note that 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 contain lactose, a sugar most adults cannot fully digest.

For this reason, they are notorious for causing digestive issues like bloating, gas, and stomach pain.

And you may 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

You 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 and cause the formation of toxic byproducts in your gut (Nutrients, 2018; Nutrients, 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.

Sources

1. Nature Reviews Gastroenterology & Hepatology (Nat Rev Gastroenterol Hepatol). Ultra-processed foods and food additives in gut health and disease. 2024.
2. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2019.
3. Microorganisms (Microorganisms). Gut Microbiota Dysbiosis: Triggers, Consequences, Diagnostic and Therapeutic Options. 2022.
4. Molecular Nutrition & Food Research (Mol Nutr Food Res). Contribution of diet to gut microbiota and its association with chronic disease risks. 2019.
5. Nutrients (Nutrients). Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study. 2018.
6. Nutrients (Nutrients). The Impact of Protein Supplementation on Gut Microbiota in Active Individuals: A Systematic Review. 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.