Beta-hydroxy beta-methylbutyric acid

Chembox new
Reference= [ [http://www.sigmaaldrich.com/catalog/search/ProductDetail/FLUKA/55453 β-Hydroxyisovaleric acid ] at Sigma-Aldrich]
ImageFile=Hydroxymethylbutyric acid.pngImageSize=150px
IUPACName=3-Hydroxy-3-methylbutanoic acid
OtherNames=β-Hydroxyisovaleric acid
Abbreviations=HMB
Section1= Chembox Identifiers
CASNo=625-08-1
PubChem=69362
SMILES=CC(C)(CC(=O)O)O
Section2= Chembox Properties
Formula=C₅H₁₀O₃
MolarMass=118.13 g/mol
Appearance=
Density=0.938 g/mL
MeltingPtC=−80
BoilingPt=88 °C at 1 mmHg
Solubility=
Section3= Chembox Hazards
MainHazards=
FlashPt=
Autoignition=

Beta-hydroxy beta-methylbutyric acid (HMB), or beta-hydroxy beta-methylbutyrate, is a metabolite of the amino acid leucine and is synthesized in the human body. It plays a part in protein synthesis and was discovered by Dr. Steve Nissen in scientific studies to purportedly increase muscle mass and decrease muscle breakdown. It should be noted however that Nissen held the original patent on the metabolite as a nutritional supplement. It can be found, in small quantities, in grapefruit, alfalfa, and catfish.

Research published in the "Journal of Applied Physiology" and other peer reviewed publications has shown that HMB may have an effect on increasing muscle weight and strength. [Nissen, SL et al. The effect of the leucine metabolite Beta-hydroxy-Beta-methylbutyrate on muscle metabolism during resistance-exercise training. J Appl Physiol 81: 2095-2104,1996] A review in "Nutrition & Metabolism" provides an in depth (129 studies) and objective analysis of HMB research. [cite journal |author=Wilson GJ, Wilson JM, Manninen AH. |title=Effects of beta-hydroxy-beta-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: A review. |journal=Nutrition & Metabolism |year=2008 |pmid=18173841 |doi=10.1186/1743-7075-5-1 |volume=5 |pages=1] The same study lists as HMBs proposed mechanisms of action the following:
* Increased sarcolemal integrity via conversion to HMG-CoA reductase
* Enhanced protein synthesis via the mTOR pathway
* Depression of protein degradation through inhibition of the ubiquitin pathway

Three grams of HMB per day may help muscles combat protein breakdown, assist in muscle repair and support increased endurance. Studies suggest its benefits may be greater for the untrained. Also, well-controlled scientific studies have found increases in muscle mass and decreases in body fat in 70 year old men. It has helped patients with chronic obstructive pulmonary disease in hospital intensive care units, muscle wasting associated with HIV or AIDS and with cancer, and trauma victims with severe injuries.Fact|date=September 2007

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.

References