How to Evaluate Protein Powder Ingredients

📌 Overview and Key Takeaways

This is a Dietitian’s guide on how evaluate protein powder ingredients.

Discover how to safely supplement your protein intake.

Last Updated
Jan 13, 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.

Protein Powder Ingredients

Which Protein Powder Ingredients Should I Prioritize?

There are many different types of protein powder, including whey, pea, soy, and egg white to name a few.

Some people will tell you that certain types of protein powder are better than others due to their amino acid composition, but this is misleading.

If you eat a balanced diet, you will be getting all of the amino acids (including the essential amino acids and BCAAs) that you need.

Moreover, excess amino acids and BCAAs are excreted as waste, which means there is no advantage to meeting more than 100% of your amino acids needs.

In case you were wondering, “essential” amino acids are the amino acids that your body needs, but cannot make on its own.

And branched-chain amino acids (BCAAs) are a type of essential amino acid that plays a key role in muscle growth and repair.

Certain protein sources contain all of the essential amino acids and high amounts of BCAAs, but this is not an advantage if you get your protein from a variety of sources.

So, most people should just pick the type of protein powder that they like or tolerate the best.

Which Protein Powder Ingredients Should I Avoid?

Not all protein powders are created equal.

And although the type of protein powder you choose does not matter, ingredients to matter.

Certain common protein powder ingredients can cause painful side effects and even long-term health problems.

Here are some of the top offenders:

🚫 Avoid Food Additives

The average protein powder contains a cocktail of food additives.

Although they are not necessarily bad for you in small quantities, the effects of regularly eating small quantities of ultra-processed additives can compound quickly.

Consuming food additives can not only cause digestive issues like bloating, diarrhea, and stomach pain, but also alter the composition of your gut microbiome – the collection of microorganisms living in your gut (North Clin Istanb, 2019).

This can lead to gut dysbiosis, or an imbalance in gut bacteria, which can contribute to chronic diseases, including obesity, type 1 diabetes, and colorectal cancer (Microorganisms, 2022; J Exp Med, 2019).

Keep in mind that your gut microbiome plays a crucial role in various physiological processes, including immune system maturation, protection against pathogens, and regulation of metabolic functions.

For this reason, when the balance of bacteria therein is disrupted, it can have a huge impact on your overall health.

⚠️ 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 also cause digestive issues.

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

Optimum Nutrition

To help you better understand how to read the ingredients list on your protein powder, I am now going to review the ingredient labels on a few popular protein powders.

The first powder on the list is Optimum Nutrition’s Gold Standard 100% Whey Protein Powder, which is the best selling protein powder in the United States.

This is far from the worst ingredient list that I have seen, but it still has its fair share of additives, including lecithin, sucralose, and artificial flavors.

Interestingly, Optimum Nutrition does not specify what type of lecithin it is using, but we can assume that it is soy lecithin given there is soy on the ingredient list.

Soy lecithin is an ultra-processed emulsifier that looks nothing like real food, meaning it should not be part of a healthy diet.

Acesulfame potassium is an artificial sweetener.

Several studies have shown that artificial sweeteners can increase cravings toward sugary and sweet foods, which can lead to binging and feelings of withdrawal (Yale J Biol Med, 2010).

Research has also associated artificial sweeteners with a higher risk of glucose intolerance, which is a precursor for pre-diabetes and diabetes (Nature, 2014).

Natural flavors, although they do not have the same bad reputation as artificial flavors, are still not something you want to put in your body.

Did you know that flavor manufacturers can add synthetic solvents, preservatives, and carriers to a flavor that qualifies as “natural” under current regulations?

If follows that “natural flavor” is basically a catch-all term for everything that a manufacturer would rather not spell out on the ingredient list.

Orgain

Orgain is one of the most popular vegan protein powders.

It is Certified Organic, which is great, but just because something is organic does not mean that it is good for you.

As you can clearly see, Orgain is full of food additives.

One of the most problematic additives in this list is erythritol as a recent study found a link between erythritol consumption and cardiovascular events (Nat Med, 2023).

The other ingredients in Orgain that concern me are the thickeners, of which there are four: acacia gum, guar gum, inulin, and xanthan gum.

Thickeners are notorious for causing painful digestive issues and even long-term gut health problems.

BSN

BSN SYNTHA-6 Whey Protein Powder has one of the worst ingredient lists I have ever seen.

I count almost 20 food additives, which is way too many!

There are several repeat offenders, including soy lecithin, natural flavors, and acesulfame potassium, and some newcomers like sucralose (an artificial sweetener) and cellulose gum (a thickener).

There is also dipotassium phosphate, which is used as a fertilizer…

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.

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. The Journal of Experimental Medicine (J Exp Med). The gut microbiome: Relationships with disease and opportunities for therapy. 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. The Yale Journal of Biology and Medicine (Yale J Biol Med). Gain weight by “going diet?” Artificial sweeteners and the neurobiology of sugar cravings: Neuroscience 2010. 2010.
6. 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.
7. Nature (Nature). Artificial sweeteners induce glucose intolerance by altering the gut microbiota. 2014
8. Nature Medicine (Nat Med). The artificial sweetener erythritol and cardiovascular event risk. 2023.