High-quality whey or soy protein (cold-pressed whey protein derived from grass-fed cows or soy protein derived from fermented soy, and free of hormones, chemicals and sugar) provides all the key amino acids for glutathione production (cysteine, glycine and glutamate) and contains a unique cysteine residue (glutamylcysteine) that is highly bioactive in its affinity for converting to glutathione.
Glutamylcysteine is a bonded cysteine molecule (cysteine plus glutamate) that naturally occurs in Bovine Serum Albumin - A fragile immune component of the whey. This unique cysteine is exclusive to whey and soy and rarely appears in other protein foods - which makes whey/soy protein the best glutathione-promoting food source.
Furthermore, whey provides critical co-factors, immunoglobulins, lactoferrin and alpha Lactalbumin (also a great source of cysteine), which together help create the right metabolic environment for high glutathione activity.
Glutathione is your body's most powerful antioxidant and has even been called "the master antioxidant." It is a tripeptide found inside every single cell in your body.
Glutathione is different from other antioxidants in that it is intracellular. It has the unique ability of maximizing the activity of all the other antioxidants, including vitamins C and E, CoQ10, alpha lipoic acid, and the fresh veggies and fruits you (hopefully) eat every day. It removes toxins from your cells and protects you from the damaging effects of radiation, chemicals, and environmental pollutants.
In fact, the main function of glutathione is to protect your cells and mitochondria from peroxidative and oxidative damage, such as what may occur during intense exercise.
Most oral glutathione supplements have been shown to be poorly absorbed and a waste of your hard-earned money, which is why consuming a good protein source to trigger your body's natural glutathione production makes sense. Fresh, uncooked meats and raw milk, and certain raw vegetables, are also excellent sources of glutathione, but they must be consumed raw to get the benefit, and many people do not do this.