Undenatured Whey Protein 

undenatured whey

Undenatured whey protein possesses an amazing ability to boost glutathione levels long term, safely and naturally, by supplying the cells with crucial bonded cysteine molecules necessary for glutathione production.

Let’s start our discussion with whey in general.

What is whey? Whey, also known as milk serum, is a constituent of milk from all mammals, including humans. The most common commercial whey comes from cow’s milk. 

Raw cow’s milk is 5-10% protein, out of which 80% is casein and 20% whey.


Whey used to be an insignificant by-product of cheese production in the dairy industry – the liquid that separates from casein solids. This liquid used to be discarded because the manufacturers could not find any application for it.

The late 1970s discovery of the nutritional benefits of proteins from whey, especially their ability to raise glutathione levels, by Dr. Gustavo Bounous at Canada’s McGill University, changed this practice and brought whey proteins into the limelight.

Unlike casein, whey contains a large group of cysteine rich proteins: alpha-lactalbumin, beta-lactoglobulin, serum albumin, lactoferrin and immunoglobulins - generally referred to as "lactalbumin" that all remain soluble in whey after separation from casein. 

These proteins are easily digestible and for this reason earned a reputation of an effective protein supplement for body builders and athletes.
But most importantly, these proteins in their undenatured form are potent glutathione precursors because of their remarkably high bonded cysteine content. Bonded cysteine is two cysteine molecules joined by disulfide bridges.

When these proteins are consumed intact with cysteine remaining bonded, they survive digestion, easily enter the bloodstream, then enter cells and are used there to form glutathione – the body’s own ultimate immune system booster.

As a comparison to cow’s milk, human breast milk contains only 40% casein, and whey is at the high level of 60% – this composition makes human breast milk an exceptional source of bonded cysteine and glutamylcysteine for a newborn. Long-term breastfeeding develops the baby’s immune system, protects against infection and incidence of childhood cancers through raising glutathione levels. The closest formulation to immune-boosting proteins of the human breast milk is cow's milk whey protein in undenatured form, produced in a way so that it maintains the critical concentration of three most bioactive whey proteins - lactoferrin, serum albumin and alpha-lactalbumin.


These above-mentioned disulfide bridges in the molecular structure of bonded cysteine are very fragile and easily destroyed by:

  • heat above 161.6 F (72 C) during pasteurization
  • prolonged exposure to oxygen (oxidation)
  • fast spinning or agitation during filtration and packaging
  • vigorous mechanical blending during rehydration
  • highly acidic liquids

Thus, denaturation of whey proteins is a breakdown in the protein structure due to above mentioned events that does not affect the food value of a whey protein, but affects its bioactivity. 

While the overly processed, denatured whey proteins are still a good source of high quality, easily digestible protein, they do not possess any immune boosting qualities.

Sometimes denatured whey proteins (and even some undenatured ones) are processed further to make them dissolve instantly in liquid, just like instant coffee or tea mixes. They may also contain added sugar, artificial sweeteners, artificial flavors or food dyes.

High quality undenatured whey protein is the protein extracted from milk through the process of cold filtration which carefully preserves the molecular structure of bonded cysteine leaving it intact throughout the entire manufacturing process under stringent pharmaceutical grade conditions.

Undenatured whey protein can thus serve as a cysteine delivery system for boosting glutathione levels and improving immune health.


If you want to raise your glutathione levels in order to boost immunity or to address a certain health issue, or if you are a competing athlete and your goal is to get the maximum out of your training and to minimize the recovery time, then you must choose a top quality undenatured whey protein with bioactive bonded cysteine.

This is what you need to keep in mind when choosing undenatured whey protein:

  1. Whether cow’s milk is obtained without the use of growth hormones, antibiotics and pesticides.
  2. Protein content – preferably, it should be a whey protein isolate, not concentrate, with at least 90% protein content, because more non-denatured whey protein means more glutathione precursors.
  3. Protein composition - the percentages of alpha-lactalbumin, beta-lactalbumin, serum albumin, lactoferrin and immunoglobulin in the protein. Research done by Dr. Bounous concludes that serum albumin level at about 9.5-10% is highly advantageous to improving the immune system because bonded cysteine and glutamylcysteine groups are the highest in serum albumin (17/molecule and 6/molecule respectively). Immunoglobulins at 25-30% are important as well because their presence in an undenatured whey protein is of clinical importance to patients whose immune systems are compromised.
  4. Glutathione precursors - the amounts of amino acids cysteine, glutamate and glycine are very important as they are building blocks for glutathione. Crucial cysteine levels should be no less than 200 mg per 10 g of whey protein.
  5. Lactose content – should be <1% for lactose intolerant people to be able to consume undenatured whey protein. Isolates are virtually lactose free.
  6. Added sugar content – should be none.
  7. Fat and cholesterol content – preferably none; isolates are virtually fat and cholesterol free, concentrates are not.
  8. Unwanted additives (artificial sweeteners, corn syrup, emulsifiers, lecithin, flavors, etc.) – additives may reduce bioactivity of undenatured whey protein, so there should be none.
  9. Check if whey protein is an instant mix product - if it mixes with liquid instantly, or without any clumping, it means that there is a certain degree of denaturation and the product is less effective.


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Further reading:

Undenatured Whey Protein Comparison

Undenatured Whey FAQ 

Types of Whey Protein

Glutathione (GSH) – what it does in your body and why it is important

Cysteine – the limiting factor in cellular glutathione production

How To Raise Glutathione

Ways to Boost Your Immune System



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