L-cysteine supplementation as an adjuvant therapy for type-2 diabetes

Can J Physiol Pharmacol. 2012 Aug;90(8):1061-4. doi: 10.1139/y2012-087. Epub 2012 Jul 11.


Diabetes remains a major public health issue. According to the American Diabetes Association, 23.5 million, or 10.7% of people in the USA aged 20 years and older, have diabetes. Type-2 diabetes is treated both by controlling the diet and with oral hypoglycemic drugs. However, for many patients, achieving a tight control of glucose is difficult with current regimens. This chapter discusses a relatively low-cost dietary supplement that could be used as an adjuvant therapy for type-2 diabetes. A review of the literature indicates that cysteine-rich whey protein improves glucose metabolism in diabetic animals and type-2 diabetic patients. Similarly, in animal studies, improvement in glucose metabolism is observed after supplementation with L-cysteine, or molecules containing a cysteine moiety. This chapter discusses the biochemical mechanisms by which L-cysteine can upregulate the insulin-dependent signaling cascades of glucose metabolism. Further studies are needed to examine whether clinical interventions using L-cysteine as an adjuvant therapy indeed help to control glycemia and vascular inflammation in the diabetic patient population.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Cysteine / therapeutic use*
  • Diabetes Mellitus, Type 2 / diet therapy*
  • Dietary Supplements*
  • Glucose / metabolism
  • Humans
  • Hypoglycemic Agents / therapeutic use*
  • Signal Transduction / drug effects
  • Up-Regulation


  • Hypoglycemic Agents
  • Glucose
  • Cysteine