What is Alpha-Hydroxybutyrate? Definition, Reference Ranges

What is α-Hydroxybutyrate?

α-Hydroxybutyrate is a by-product of glutathione production. Levels of alpha-hydroxybutyrate in the urine may reflect levels of glutathione production.

What is Glutathione?

Glutathione is an important antioxidant that can prevent damage to cellular components caused by reactive oxygen species such as free radicals, peroxides, lipid peroxides, and heavy metals.

Glutathione is constantly being used up in the removal of toxic molecules and prevention of oxidative damage.

α-Hydroxybutyrate is a by-product from the process in which the body forms more glutathione. When that process is running at high rates, α-hydroxybutyrate excretion is increased.

alpha-hydroxybutyrate high low reference ranges value glutathione synthesis

High α-Hydroxybutyrate levels:

All of the conditions associated with increased α-Hydroxybutyrate excretion may be related to increased rates of hepatic glutathione synthesis from methionine. Elevated α-Hydroxybutyrate thus shows increased flow through the hepatic glutathione synthesis pathway as required during times of increased oxidative stress or for detoxification functions.

  • Smoking, poor diet, and lack of exercise significantly inhibit the activity of AHBD (=α-hydroxybutyrate dehydrogenase catalyzes oxidation of AHB to acetate), suggesting that urinary elevation of α-Hydroxybutyrate may be related to these factors via increased glutathione demand.
  • High α-Hydroxybutyrate is also found during phases of increased lymphocyte destruction in infectious diseases such as measles.
  • Elevated α-Hydroxybutyrate is found in birth asphyxia and in inherited metabolic diseases such as “cerebral” lactic acidosis, glutaric aciduria type II, dihydrolipoyl dehydrogenase deficiency, and propionic acidemia.
  • α-Hydroxybutyrate is also an early marker for both insulin resistance and impaired glucose regulation that appears to arise due to increased lipid oxidation and oxidative stress.
  • Elevated levels of alpha-hydroxybutyrate in the plasma is a good marker for early-stage type II diabetes.


  • α-Hydroxybutyrate Is an Early Biomarker of Insulin Resistance and Glucose Intolerance in a Nondiabetic Population [L]
  • Clinical Applications of Urinary Organic Acids. Part 1: Detoxification Markers [L]
  • α-Hydroxybutyrate Is an Early Biomarker of Insulin Resistance and Glucose Intolerance in a Nondiabetic Population [L]
  • Serum α-hydroxybutyrate (α-HB) predicts elevated 1 h glucose levels and early-phase β-cell dysfunction during OGTT [L]


The information on is NOT intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice.


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