Lysine ingestion markedly attenuates the glucose response to ingested glucose without a change in insulin response

Am J Clin Nutr. 2009 Aug;90(2):314-20. doi: 10.3945/ajcn.2008.27381. Epub 2009 Jun 24.


Background: Ingested proteins are known to stimulate a rise in insulin and glucagon concentrations. In our effort to explain this effect, we have begun to measure the effect of individual amino acids.

Objectives: The objectives were to determine the effect of lysine ingestion on insulin and glucagon concentrations and whether the effect is moderated by glucose ingestion.

Design: Thirteen healthy subjects were studied on 4 occasions. Water, 25 g glucose, 1 mmol lysine/kg lean body mass, or lysine plus glucose was given on separate occasions at 0800 after a 12-h fast. Serum lysine, glucose, insulin, and glucagon were measured during a 2.5-h period. The amount of lysine provided was equivalent to that present in a 672-g (24-oz) steak.

Results: Lysine ingestion resulted in an approximately 3-fold increase in lysine concentration and in a small decrease in glucose concentration. When lysine was ingested with glucose, the 2.5-h glucose area response decreased by 44% (P < 0.02). Lysine alone increased the insulin area response modestly; the insulin increase when lysine was ingested with glucose was similar to that when only glucose was ingested. Lysine stimulated an increase in glucagon (P < 0.02), whereas glucose decreased glucagon.

Conclusions: Lysine ingestion results in a small decrease in serum glucose and an increase in glucagon and insulin concentrations. Lysine ingested with glucose dramatically attenuated the glucose-stimulated glucose response, but there was no change in insulin response. Whether similar effects will be observed with more physiologic doses of lysine remains to be determined.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Area Under Curve
  • Blood Glucose / drug effects
  • Blood Glucose / metabolism*
  • Cross-Over Studies
  • Drug Synergism
  • Fasting
  • Female
  • Glucagon / blood
  • Glucose / administration & dosage
  • Glucose / metabolism
  • Glucose / pharmacology*
  • Humans
  • Insulin / blood*
  • Insulin / metabolism
  • Insulin Secretion
  • Lysine / administration & dosage
  • Lysine / metabolism
  • Lysine / pharmacology*
  • Male
  • Middle Aged
  • Satiation / drug effects
  • Young Adult


  • Blood Glucose
  • Insulin
  • Glucagon
  • Glucose
  • Lysine