NOW Liver Refresh is a proprietary blend of herbs and nutrients designed to support healthy liver function. Now Liver Refresh contains Milk Thistle Extract, which has been shown in clinical and non-clinical studies to support the liver, as measured by standard liver enzyme laboratory tests. In addition, Liver Refresh contains N-acetyl cysteine and L-methionine, two amino acids known to enhance the production of glutathione in the liver. L-glutathione, a major cellular antioxidant plays an essential role in liver detoxification mechanisms.