How to Find the Best Easily Digestible Protein Powder​

📌 Overview and Key Takeaways

This is a Certified Nutrition Coach’s guide on how to find the best easily digestible protein powder​.

Discover how to meet your protein needs without upsetting your stomach.

Last Updated
Aug 17, 2026

Author and Medical Reviewer

Jack, CNC

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

Jack’s Story | Jack on LinkedIn | Jack in Forbes 30 Under 30

Disclaimer: This communication is for general informational purposes only and is not a substitute for personalized medical advice.

Easily Digestible Protein Powder​

What Affects Protein Powder Digestion?

Digestion is the complex process that breaks down food into nutrients your body can absorb and use.

Amino acids – the building blocks of protein – are digested at a rate of 1.3 grams to 10 grams an hour (Int J Sport Nutr Exerc Metab, 2006).

The degree to which they are digested also varies, from 70 to 99% (Crit Rev Food Sci Nutr, 2023)

The exact rate and degree of digestion depends on the type of protein, how it was processed, the presence of other compounds or ingredients, and individual physiology.

For example, in individuals over age 65, gastrointestinal (GI) conditions can reduce protein digestibility by up to 20% (Food Res Int, 2023).

Moreover, protein that is hydrolyzed – broken down into smaller pieces using enzymes or chemicals – might be digested faster (Am J Clin Nutr, 2009).

Note that faster digestion does not equate more or better muscle-building (Am J Clin Nutr, 2009).

In short, what makes one protein powder easier to digest than another is multivariable and highly individual.

Plus, the rate at which and degree to which a protein is digested does not tell you much about the overall digestive experience (how it makes you feel).

This matters as much, if not more.

What Is the Best Easily Digestible Protein Powder​​​?

There are several methods used to determine how easy a dietary protein is to digest.

The most widely used method is the protein digestibility corrected amino acid score (PDCAAS), which measures amino acid composition and digestibility.

Both eggs and milk have a PDCAAS of 1, which is the highest score possible and an indication that they are easy to digest.

The PDCAAS does not consider how other nutrients might affect digestion, however.

For instance, milk contains both lactose and casein, both of which are notorious for causing digestive issues.

Lactose is a milk sugar that most adults cannot fully digest (Nutrients, 2024).

Casein is a milk protein that can release a bioactive peptide during digestion that has been linked to digestive issues (Adv Nutr, 2017).

Casein also forms a gel-like substance in your stomach that slows down digestion, which can contribute to bloating, constipation, and other GI side effects. (Crit Rev Food Sci Nutr, 2023).

Basically, although there are scientific methods used to measure protein digestibility, they do not account for how other macronutrients can affect the overall digestive experience.

Moreover, unless you are consuming a single-ingredient protein powder, you also have to consider how added ingredients affect digestion.

🚫 Avoid Food Additives

Some people report that certain food additives, particularly emulsifiers, thickeners, and artificial sweeteners, upset their stomach.

Regularly consuming ultra-processed ingredients like these can also alter the composition and function of your gut microbiome – the community of microorganisms living in your digestive tract (North Clin Istanb, 2020).

These shifts, known as gut dysbiosis, can impair digestion and contribute to the development of chronic digestive problems like irritable bowel syndrome (IBS) (Lancet Gastroenterol Hepatol, 2026; JGH Open, 2021).

It is important to note that much of this research is still emerging, so more studies are needed to clarify these relationships.

That said, the preliminary findings suggest that because protein shakes and powders are something you consume regularly, if not every day, the cumulative effects of small amounts of potentially harmful ingredients is worth taking seriously.

⚠️ Here is a list of the most common food additives in protein shakes and powders:

• 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 an ingredient 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 a problem for everyone, can cause digestive issues too.

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

But as you just learned, you might be sensitive to dairy-based proteins, particularly casein, even if you are not lactose intolerant.

🚫 Avoid Protein Concentrates and Isolates

I also recommend avoiding protein concentrates and isolates.

Most protein shakes and powders 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 you break them down.

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

For example, one study shows that regularly consuming protein concentrates and isolates might disrupt your gut microbiome (Nutrients, 2018).

Another study shows that it could cause the formation of toxic byproducts in your gut (Mol Nutr Food Res, 2024).

Although further research is needed, individuals with sensitive stomachs can play it safe by choosing protein shakes and powders made from minimally-processed protein sources like egg whites and almonds.

Our customers find them to be more gut-friendly.

Order Samples to see for yourself.

Sources

1. Critical Reviews in Food Science and Nutrition (Crit Rev Food Sci Nutr). Effect of processing on in vitro digestibility (IVPD) of food proteins. 2023.
2. Food Research International (Food Res Int). Comparison of protein in vitro digestibility under adult and elderly conditions: The case study of wheat, pea, rice, and whey proteins. 2023.
3. American Journal of Clinical Nutrition (Am J Clin Nutr). Ingestion of a protein hydrolysate is accompanied by an accelerated in vivo digestion and absorption rate when compared with its intact protein. 2009.
4. International Journal of Sport Nutrition and Exercise Metabolism (Int J Sport Nutr Exerc Metab). A review of issues of dietary protein intake in humans. 2006.
5. Nutrients (Nutrients). Prebiotic Strategies to Manage Lactose Intolerance Symptoms. 2024.
6. Advances in Nutrition | Journal (Adv Nutr). Systematic Review of the Gastrointestinal Effects of A1 Compared with A2 β-Casein. 2017.
7. Critical Reviews in Food Science and Nutrition (Crit Rev Food Sci Nutr). Milk proteins: Processing, gastric coagulation, amino acid availability and muscle protein synthesis. 2023.
8. Northern Clinics of Istanbul (North Clin Istanb). Food additives and microbiota. 2020.
9. The Lancet Gastroenterology and Hepatology (Lancet Gastroenterol Hepatol). Mechanisms and pathophysiology leading to development of small intestinal microbial dysbiosis. 2026.
10. JGH Open (JGH Open). Gut microbiota dysbiosis in functional gastrointestinal disorders: Underpinning the symptoms and pathophysiology. 2021.
11. Nutrients (Nutrients). Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study. 2018.
12. 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 Certified Nutrition Coach and reviewed by a Registered Dietitian. We rely on peer-reviewed research and trusted medical sources, and regularly update our content to ensure accuracy and clarity.