beta-Hydroxy beta-methylbutyric acid

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β-Hydroxy β-methylbutyric acid[1]
Hydroxymethylbutyric acid.png
IUPAC name
3-hydroxy-3-methylbutanoic acid
Other names
β-Hydroxyisovaleric acid
3-Hydroxyisovaleric acid
625-08-1 YesY
Abbreviations HMB
ChEBI CHEBI:37084 YesY
ChemSpider 62571 YesY
Jmol-3D images Image
PubChem 69362
UNII 3F752311CD N
Molar mass 118.131 g/mol
Density 0.938 g/mL
Melting point −80 °C (−112 °F; 193 K)
Boiling point 88 °C (190 °F; 361 K) at 1 mmHg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 N verify (what isYesY/N?)
Infobox references

β-Hydroxy β-methylbutyric acid (HMB), or β-hydroxy β-methylbutyrate, is a metabolite of the essential amino acid leucine and is synthesized in the human body. Its part in protein synthesis was discovered by Steven L. Nissen at Iowa State University.[2] It has been used in scientific studies to purportedly increase muscle mass and decrease muscle breakdown. Nissen held the original patent on the metabolite as a nutritional supplement. It was discovered in pigs and small quantities can also be found in grapefruit, alfalfa, and catfish. As a supplement it is usually sold as the calcium salt calcium beta-hydroxy-beta-methylbutyrate.

Research published in the Journal of Applied Physiology has shown that HMB may have an effect on increasing muscle weight and strength.[2] A review in Nutrition & Metabolism provides an in depth and objective analysis of HMB research. [3] The same study lists as HMB's proposed mechanisms of action the following:

The human body produces about 0.2-0.4 grams per day. Standard doses in research studies have been 1.5 to 3.0 grams per day, usually divided into two doses. Toxicity at these doses is unlikely, as the no-observed-adverse-event-level (NOAEL) in rats is between 2.48 to 2.83 g/kg BW per day, roughly equivalent to 70 to 100 g/day in humans.[4]


  1. ^ β-Hydroxyisovaleric acid at Sigma-Aldrich
  2. ^ a b Nissen S, Sharp R, Ray M et al. (November 1996). "Effect of leucine metabolite beta-hydroxy-beta-methylbutyrate on muscle metabolism during resistance-exercise training". J. Appl. Physiol. 81 (5): 2095–104. PMID 8941534. 
  3. ^ Wilson GJ, Wilson JM, Manninen AH. (2008). "Effects of beta-hydroxy-beta-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: A review.". Nutrition & Metabolism 5: 1. doi:10.1186/1743-7075-5-1. PMC 2245953. PMID 18173841. 
  4. ^ Fuller JC Jr, Arp LH, Diehl LM, Landin KL, Baier SM, Rathmacher JA. (February 2014). "Subchronic toxicity study of β-hydroxy-β-methylbutyric free acid in Sprague-Dawley rats". Food Chem Toxicol. 67: 145–53. doi:10.1016/j.fct.2014.02.025. PMID 24576552.