There are two sulfur-containing amino acids: cysteine and methionine. Methionine is essential, meaning it must be obtained through the diet. Animal proteins are considered better sources of methionine and cysteine than plant proteins. For healthy adults, numerous organizations recommend 13 mg/kg daily intake of sulfur amino acids, which is equivalent to 884 mg for a 150 pound healthy adult1.

This ingredient can be found in the following products in United States:


  1. van de Poll MC, Dejong CH, Soeters PB. Adequate range for sulfur-containing amino acids and biomarkers for their excess: lessons from enteral and parenteral nutrition. J Nutr. 2006;136:1694S-700S.