Glutathione is commonly referred to as the master antioxidant due to its importance in human health. It's synthesized in the body from the amino acids cysteine, glutamic acid and glycine. Of these three amino acids, cysteine is typically the rate limiting factor in glutathione production since it's relatively rare in food. Therefore, it's important to ensure adequate intake of cysteine from other sources.
The two best sources of cysteine are:
Undenatured Whey Protein [Buy]
Undenatured (cold processed) whey protein naturally contains cysteine and other beneficial compounds such as lactoferrin and immunoglobulins.
N-Acetyl Cysteine (NAC) [Buy]
NAC is a modified and stabilized form of cysteine. The typical dose is 600 mg / day. There have been some (largely unsubstantiated) concerns about the safety of taking NAC daily but cycling this supplement should minimize any potential risks.
Apart from whey protein and NAC, there are several other supplements that have been shown to support the synthesis or recycling of glutathione. The most effective of these are:
There is one other option for raising glutathione levels that's worth mentioning - taking a liposomal form such as Upgraded Glutathione™ or Lypo-Spheric™ GSH. These products wrap glutathione in nanoparticles of phospholipids, which enable it to be digested more effectively (normally glutathione would be destroyed during digestion). Unfortunately, these products are very expensive. Also, because glutathione is tightly regulated by the body via a negative feedback mechanism, taking a lot of glutathione in this form may downregulate the body's own production.
I personally take Milk Thistle and Alpha Lipoic Acid every day, undenatured whey protein most days and NAC about 3 - 4 times a week. About once a week I'll take some liposomal glutathione after exposing myself to a large amount of toxins, such as questionable restaurant food. The results of a follow-up SpectraCell micronutrient test showed my glutathione and cysteine levels increased significantly after following this regimen.