CysteinePeP is a hydrolysed whey protein powder that is specifically designed to support glutathione production via the liver. Cysteine is an important precursor to glutathione, one of the most powerful antioxidant nutrients.* ... Glutathione fulfills most of its many biological functions intracellularly, but is not well transported into cells as a tripeptide. Most orally ingested glutathione must first be broken down to cysteine, absorbed, then re-synthesized by the liver.* ... Cysteine peptides are easier for the body to absorb.* ... Animal studies have shown that cysteine supplementation increases levels of GSH, and can help restore GSH levels after depletion due to oxidative stress.* ... In human studies, subject supplementing with cysteine have reported increased levels of energy.* ... This product contains whey, so tolerance will vary.*