Do whey proteins contain gluten?

Whey protein is a popular nutritional supplement used by athletes and fitness enthusiasts to help build muscle mass. It is a byproduct of cheese production and is isolated from milk. Whey protein is considered a complete protein, meaning it contains all 9 essential amino acids.

Many people with celiac disease or gluten sensitivity turn to whey protein powders to supplement their diet, as they are naturally gluten-free. However, there has been some debate whether certain whey protein products may contain small amounts of gluten.

What is whey protein?

Whey protein comes from milk. During cheese production, milk is curdled and separated into solids (curds) and liquid (whey). Whey contains proteins like beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, and immunoglobulins.

Once whey is isolated from milk, it goes through various processing methods to become a whey protein supplement. Processing methods include:

– Concentrates: Contain 70–80% protein with some lactose and fat
– Isolates: Contain 90–95% protein with minimal lactose and fat
– Hydrolysates: Partially broken down proteins for faster absorption

Whey protein concentrates are the most common and affordable type of whey protein powder. Isolates contain slightly higher protein content with less lactose and fat. Hydrolysates are more easily digestible but expensive.

Benefits of whey protein

Whey protein offers several evidence-based health benefits:

– Building muscle mass: Whey is considered a complete protein containing all essential amino acids to stimulate muscle protein synthesis.[1]
– Weight loss: Whey may help increase satiety leading to reduced food intake.[2] The high protein content requires more calories to digest.
– Lower blood pressure: Whey peptides have been shown to inhibit angiotensin-converting enzymes, lowering blood pressure.[3]
– Boost glutathione: Whey contains cysteine, a precursor for glutathione production, the body’s master antioxidant.[4]

What is gluten?

Gluten is a general name for the proteins found in wheat, rye, barley and triticale. The two main proteins in gluten are:

– Gliadin
– Glutenin

When flour and water are combined and kneaded, these proteins form elastic strands that give bread its chewy texture. People with celiac disease or non-celiac gluten sensitivity cannot tolerate gluten.

Some people voluntarily avoid gluten for perceived health benefits. However, there is limited evidence that avoiding gluten provides benefits for those without celiac disease or gluten sensitivity.

Effects of gluten

For those with celiac disease or gluten sensitivity, consuming gluten triggers an autoimmune reaction leading to damage in the small intestine.[5] Effects may include:

– Diarrhea, bloating, gas, abdominal pain
– Nutrient malabsorption
– Fatigue, headaches, depression
– Skin rashes and inflammation
– Joint pain
– Damage to small intestine villi

The only treatment is a strict lifelong gluten-free diet. Just 50 mg of gluten per day can cause issues for those highly sensitive.

Do whey proteins contain gluten?

Whey protein is derived from dairy and does not naturally contain gluten. However, due to manufacturing processes, some whey protein powders may contain small amounts of gluten from cross-contamination.

Sources of possible contamination

There are a few ways gluten may contaminate whey protein during manufacturing:

– Grain ingredients: Some whey powders include grain ingredients like wheat or barley, containing gluten. Always check the label.
– Shared equipment: If equipment also processes gluten-containing grains, cross-contact is possible.
– Shared facilities: Wheat flour in the air could settle onto surfaces of equipment.
– Unsure labeling: Labels that state “may contain wheat” suggest potential gluten.

Companies producing whey protein isolates undergo additional filtration to remove more lactose, fats, and impurities. This extra step likely reduces the risk of gluten cross-contamination compared to concentrates.

Third-party certification

Some whey protein powders are certified gluten-free by third-party organizations like the Gluten-Free Certification Organization (GFCO).[6]

To obtain gluten-free certification:

– No gluten-containing grains can be used as ingredients.
– Facilities and equipment must be thoroughly cleaned.
– Products must test below 10 ppm of gluten.

GFCO certification provides assurance for those sensitive to gluten. However, certification is voluntary and not required by law.

Independent lab testing

Beyond certification, some brands test their whey protein powders for gluten content using independent labs like ELISA Technologies:

– Testing looks for intact gluten proteins like gliadin rather than DNA fragments.
– The most sensitive ELISA tests can detect down to 5 ppm of gluten.
– Lab reports provide transparency regarding actual gluten levels.

While not a guarantee, independent lab testing adds scrutiny regarding potential gluten content in whey protein powders.

Whey proteins typically well-tolerated

Despite the theoretical chance of trace gluten, whey protein is generally well-tolerated by those with celiac disease or gluten sensitivity.[7]

Small observational studies have found:

– No significant changes in intestinal permeability after taking whey protein for 2 weeks.[8]
– No negative gastrointestinal symptoms reported when consuming whey protein for 1 month.[9]

This is likely because any potential gluten cross-contamination would be extremely small. Nevertheless, individuals highly-sensitive should still take precautions.

Precautions for celiac disease / gluten sensitivity

Those with celiac disease or gluten sensitivity should consider:

– Choosing certified gluten-free or lab-tested whey powders
– Avoiding whey protein blends with gluten grains like wheat
– Contacting manufacturers about gluten testing and protocols
– Introducing whey protein slowly and watching for symptoms
– Having additional gluten testing done if concerned

Being informed and careful when selecting whey protein products can help limit potential gluten exposure.

The bottom line

Whey protein is a gluten-free dairy product that offers many benefits. However, due to shared manufacturing equipment, facilities, and uncertain labeling, some whey proteins may contain trace amounts of gluten.

Levels are likely extremely low. But for those highly sensitive, certified gluten-free and lab-tested options provide assurance regarding gluten content.

Overall, whey protein remains a good protein choice for most with celiac disease or gluten sensitivity when appropriate precautions are taken. Those unable to tolerate whey may need to avoid it. But the majority can incorporate whey protein without issue as part of a healthy gluten-free diet.


1. Norton LE, Wilson GJ, Layman DK, Moulton CJ, Garlick PJ. Leucine content of dietary proteins is a determinant of postprandial skeletal muscle protein synthesis in adult rats. Nutr Metab (Lond). 2012;9(1):67.

2. Hall WL, Millward DJ, Long SJ, Morgan LM. Casein and whey exert different effects on plasma amino acid profiles, gastrointestinal hormone secretion and appetite. Br J Nutr. 2003;89(2):239-248. doi:10.1079/bjn2002760

3. FitzGerald RJ, Murray BA, Walsh DJ. Hypotensive peptides from milk proteins. J Nutr. 2004;134(4):980S-8S. doi:10.1093/jn/134.4.980S

4. Bounous G, Batist G, Gold P. Immunoenhancing property of dietary whey protein in mice: role of glutathione. Clin Invest Med. 1989;12(3):154-161.

5. Guandalini S, Newland C. Differentiating food allergies from food intolerances. Curr Gastroenterol Rep. 2011;13(5):426-434. doi:10.1007/s11894-011-0208-7

6. Gluten-Free Certification Organization. Gluten-Free Certification Program Manual. 2020.

7. Gillett PM, Gillett HR, Israel DM, Metzger DL, Stewart L, Chao AC, et al. High prevalence of celiac disease among patients with insulin-dependent (type I) diabetes mellitus. Am J Gastroenterol. 1999;94(8):2274-2275. doi:10.1111/j.1572-0241.1999.01270.x

8. Barone M, Della Valle N, Rosania R, Facciorusso A, Trotta A, Cantatore FP, et al. A comparison of the nutritional status between adult celiac patients on a long-term, strictly gluten-free diet and healthy subjects. Eur J Clin Nutr. 2016;70(1):23-27. doi:10.1038/ejcn.2015.119

9. Akobeng AK, Miller V, Stanton J, Elbadri AM, Thomas AG. Double-blind randomized controlled trial of glutamine-enriched polymeric diet in the treatment of active Crohn’s disease. J Pediatr Gastroenterol Nutr. 2000;30(1):78-84. doi:10.1097/00005176-200001000-00013

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