Prairie Naturals NAC 100 N-Acetyl L-Cysteine - 60 caplets - prevents vitamin E deficiency. Sources of antioxidants that fight/protect against free radicals and protects fat in body tissues from oxidation. Non-GMO, Gluten…N Acetyl Cysteine (NAC) is a precursor to the essential sulfur containing amino acid L cysteine, found in high protein foods such as eggs, chicken and turkey. Often referred to as the building blocks of protein, amino acids like cysteine are essential to body function and help with various processes such as building muscle or regulating immune function. Prairie Naturals NAC 1000 is the most potent dose of N Acetyl Cysteine available in Canada.