What to Look for When Buying Protein Powder

📌 Overview and Key Takeaways

This is a Dietitian’s guide on what to look for when buying protein powder.

Discover the top ingredients to avoid when buying protein supplements.

Last Updated
Jan 23, 2026

Author and Medical Reviewer

Written by Kayla Kamen, MS, RD

Kayla Kamen is a Registered Dietitian with a MS in Nutrition.

Medically reviewed by Jennifer Fossett, PA-C

Jennifer Fossett is a Physician Assistant with a BA in Nutritional Sciences.

How to Evaluate Protein Powder Ingredients

What to Embrace

Given how crowded the protein supplement market has become, shopping for a new protein powder can be stressful and expensive.

There are literally thousands of different options, each with different ingredients and supposed benefits.

And there is nothing worse than spending $50 on a new protein supplement, only to find out that it upsets your stomach or that you hate how it tastes.

Fortunately, if you feel overwhelmed, or if you just want advice on what to look for when buying protein powder, you have come to the right place.

I have sold protein powder for 5+ years, have worked with tens of thousands of customers, and am eager to share what I have learned.

The first thing most people consider when evaluating a protein powder is price, particularly price per serving.

They tend to consider taste and texture, which involves reading reviews from other customers.

And believe it or not, most customers stop there.

That is, only a few go on to read the Nutrition Facts or ingredient list, which amazes me.

The ingredient list is where you should start when evaluating a protein powder.

In fact, I would argue that it is the variable that matters most.

Variables like price, taste, texture, and even protein content or amino acid profile do not matter much if a protein powder is made from ultra-processed or artificial ingredients.

So, start with the ingredient list, and look for ingredients you can find in nature or make at home.

Anything else is probably not something you want to put in your body on a regular basis.

What to Avoid

Many protein powders are made with ingredients known to cause painful digestive issues and even long-term health problems.

Among these ingredients are food additives, dairy-based proteins, and protein concentrates and isolates.

🚫 Avoid Food Additives

Regularly eating food additives like artificial sweeteners, emulsifiers, thickeners, and flavorings can alter the composition and function of your gut microbiome (North Clin Istanb, 2019).

This can lead to gut dysbiosis, or an imbalance in gut bacteria, which can contribute to chronic diseases like obesity, type 2 diabetes, and even certain cancers (Microorganisms, 2022; Nat Rev Dis Primers, 2019).

Keep in mind that your gut does more than just help you digest food; it also influences things like metabolism, immunity, and inflammation.

⚠️ 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 digestive issues 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

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 and cause the formation of toxic byproducts in your gut (Nutrients, 2018; Mol Nutr Food Res, 2024).

You 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. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2019.
2. Microorganisms (Microorganisms). Gut Microbiota Dysbiosis: Triggers, Consequences, Diagnostic and Therapeutic Options. 2022.
3. Nature Reviews Disease Primers (Nat Rev Dis Primers). Role of the gut microbiota in nutrition and health. 2019.
4. Nutrients (Nutrients). Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study. 2018.
5. 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.