From the Manufacturer:
"Great for promoting lean muscle mass and healthier blood glucose level! How Does L-Cysteine Work? L-cysteine is an important amino acid that supports numerous functions in your body. It is used to help manufacture L-taurine and L-glutathione. L-taurine is important because it plays a key role in central nervous system function, assists in regulating blood pressure, maintaining good vision and eye function and promotes fat burning and muscle building. L-glutathione is essential for immune system function, cellular function and improved nerve signals.
Supplementing with L-cysteine may elevate your NAC (N-acetyl cysteine) level. NAC has been shown to help facilitate lean muscle mass. L-cysteine is also a component of human hair-research has shown it may support overall hair health and hair diameter. Plus, this nutrient is a key component of insulin:
L-cysteine can be converted into glucose when blood glucose levels are low, and this may be particularly beneficial toward energy production."