Cysteine In Whey Protein

What Protein Powder Contains the Most Cysteine? AGN Roots Grass-fed Whey Protein Isolate

Cysteine & Grass Fed Whey Protein

AGN Roots Grass-Fed Whey protein has an industry-leading concentration of Cysteine per 25 grams protein. In this article, we discuss the critical role of Cysteine and why grass-fed whey protein, in particular, contains more of this powerful amino acid than whey derived from conventional milk. 

What is Cysteine?

Cysteine is considered a non-essential amino acid. Increasing your body's Cysteine levels can be achieved both by the consumption of cysteine-rich foods like egg yolks and by the body's natural synthesis of Cysteine through the essential amino acid, methionine. 

Cysteine gained notoriety in the last decade as a stand-alone supplement and also an emergency room treatment.

Cysteine's unique ability to bind with toxic levels of acetaminophen (overdosing on "Tylenol") that otherwise can be severely damaging to the liver has made Cysteine supplementation more popular for everyday liver health. 

One of the most attractive functions of Cysteine, however, is that it serves as a precursor to the body's most significant antioxidant, Glutathione (GSH). Without Cysteine, the body cannot produce glutathione naturally.

With more studies having gained consensus that supplementing GSH isn't as near as impactful as the body's natural production of it, Cysteine, as you can imagine, is growing in popularity.

Learn More: How to increase Glutathione levels?

What are the Benefits of Cysteine?

Stimulates Antioxidant Activity – As a precursor to one of the body's most significant antioxidants, glutathione; Cysteine plays a critical role in protecting your cells from the effects of free radicals (molecules that have become unstable and thus damage nearby cells).

Immune Support – The antioxidant benefits of Cysteine and Glutathione also provide immune support and the maintenance of a robust immune system. Cysteine is known to prime your T-cells to produce more infection-fighting constituents.

Detoxification – Cysteine serves a critical role in the detoxification of the liver. Cysteine will bind to various chemicals and toxins, including heavy metals, and then prepare the body for excretion. Cysteine has also been known to breakdown the proteins found in mucous that can settle in the lungs.

Thermal Denaturing Resistance – Cysteine naturally fortifies the tertiary protein structures by producing more crosslinking bonds.  As Cysteine builds more bonds (disulfide bridges), the various bending moments of the helixes endemic to the tertiary structure gain stability.  The more stable the tertiary structure, the more resistant to thermal denaturing the entire protein structure becomes. As a result of denaturing being less prevalent, the bio-availability of the protein during the critical stages of processing where heat is applied, such as pasteurization and atomizing, remains high. 

Learn More: The dangers of Heavy Metals in whey protein!

Cysteine in Whey Protein

Cysteine is found in high protein foods and naturally found in tuna, poultry, lentils, oatmeal, sunflower seeds, onions, legumes, broccoli, & brussels sprouts.

The number of vegetables one would have to consume to reach the levels of Cysteine commensurate with a single serving of grassfed whey protein isolate may prove to be daunting.

Dairy protein is, however, very rich in Cysteine and doesn't require you to overeat. Foods like cheese, yogurt, milk, just like whey protein powder contain high concentrations. Consuming cysteine-rich foods and supplementing with whey protein supports the body's natural production of Glutathione (GSH).

What Whey Protein Contains the Most Cysteine?

As the building blocks of protein, amino acids are naturally occurring in all whey protein powders. The most transparent companies will publish their amino acid profile. At AGN Roots, we pride ourselves on having one of the most substantial Amino Acid profiles in the grassfed whey protein space.

Cysteine in AGN Roots Grass Fed Whey

AGN Roots Grass Fed whey contains the highest concentration of Cysteine per serving of protein for many reasons, with 100% of them a result of grassfed whey sourcing and processing.

Grassfed Whey Protein Contains The Most Cysteine for Glutathione Production

Whey Protein Powder with Highest Cysteine Levels

If Cysteine is a naturally occurring amino acid in whey protein, why do the grams per serving vary from product to product? For example, in reviewing our competitors, the quantity of Cysteine published ranged from 180mg - 730mg per serving.

Analyzing a brand's amino acid profile is analogous to looking under the hood of a car.  The paint job and bodywork of a hot-rod are comparable to the marketing claims of the whey protein product, where the engine is like the amino acid profile. All that matters is the engine, just like all that matters is the quality of the protein's amino acid profile.

The factors outlined below have a direct impact on the quantity of Cysteine in whey protein and highlight why AGN Roots Grass-Fed Whey, at 730mg of Cysteine per serving 25 grams protein), has set itself apart from the field. These factors include processing techniques, sourcing, high animal welfare practices, and of course, stress-free livelihoods of our animals.

Undenatured & Cold Processed Grassfed Whey

AGN Roots Grassfed Whey uses cold micro-filtration. Cold-Processing preserves the natural protein structure of Cysteine as there is no exposure to heat that can damage the micro-nutrients. Also, the mesh size (125 microns) of the micro-filter is large enough to allow Cysteine to permeate through the membranes without structural damage.

Additionally, unlike most mass-produced tub brands, AGN Roots Grassfed Whey does not use the ion-exchange method. This method is proven to be error-prone, too often leading to the deformation (denaturing) of the tertiary and quaternary protein structures resulting from pH manipulation (to low-acidic). Once the pH drops, some amino acids, including Cysteine, become ionized and are removed during the filtration process.

The cysteine or cystine compound must remain intact and undenatured during the manufacturing process to give your body the best chances to produce glutathione levels maximally, after-all, this is what we are after!

Learn More: Non-denatured & Undenatured Whey Protein

Year-round, Grass-Fed Friesian Jersey Cows

Research shows that a cow's milk composition, including amino acids, is affected by the cattle breed and the health & happiness of the animal. Additionally, 60% of the amino acids used to build milk proteins are much dependent on the cow's diet. The difference in milk from a grassfed ruminant versus a ruminant forced to eat grain-rich concentrates is staggering in terms of whey protein macro-nutrients (quality).

Unlike the famous U.S. grain-fed Holstein cattle farms, at AGN roots, our whey is sourced from Southeast coastal Irish farms made up of only Friesian-Jersey Crosses.  Jersey cattle produce milk with the highest protein concentration and quality of all the dairy cattle breeds. Likewise, Friesian cattle naturally have the second-highest protein yield. Though Holstein cattle produce the highest quantity of milk bar none, the resources required for Holsteins to produce a comparable protein yield are not feasible.

There is also a direct correlation between diet and amino acid concentration. At AGN Roots, our Friesian Jersey cattle are truly grass-fed year-round on open pasture. Their high-quality diet improves the rumen function and the efficiency of milk production, yielding high-quality whey with higher levels of amino acids, including Cysteine. It's not just Cysteine that's in high concentration compared to the industry; AGN Roots Grassfed Whey also contains the highest concentration of naturally occurring BCAAs (Branched-Chain Amino Acids) and contains no artificial sweeteners.

Learn More: Sucralose vs. Stevia vs. Aspartame vs. Natural Sweeteners
Learn More: Grassfed Whey & BCAA Density

Happy Cows Produce Milk with the Highest Cysteine

As mentioned above, not only do breed & diet affect milk composition, but health and welfare also play a role. We also believe that happy cows make the best whey. Our animals live their entire lives on open pasture with a dependable line of sight to food, water, bedding, and each other.

In summary, not all whey is created equal. Look for amino acid profiles to help tell the truth about sourcing. To maximize your cysteine and glutathione production from grassfed whey isolate, AGN Roots Grass Fed Whey provides the most significant micro & macro-nutrient concentrations available. It is genuinely grass-fed whey, sourced the right whey!

Coffey, E.L., et al. "Milk Production and Fertility Performance of Holstein, Friesian, and Jersey Purebred Cows and Their Respective Crosses in Seasonal-Calving Commercial Farms." Journal of Dairy Science, 28 Apr. 2016,
Linn, J.G. "Factors Affecting the Composition of Milk from Dairy Cows." National Center for Biotechnology Information, 1988,
Kerksick, Chad, and Darryn Willoughby. "The Antioxidant Role of Glutathione and N-Acetyl-Cysteine Supplements and Exercise-Induced Oxidative Stress." National Center for Biotechnology Information, 9 Dec. 2005,
"N-Acetyl Cysteine (Nac): Uses, Side Effects, Interactions, Dosage, and Warning.WebMD, WebMD,
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Outstanding. I really feel confident about ordering this product based on they Cysteine content and best practices and will be ordering regularly off of Amazon. Great price too thanks again

Edward Faust

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