beta-Hydroxy beta-methylbutyric acid

β-Hydroxy β-methylbutyric acid
Structure diagram, conjugate acid

Structure diagram, conjugate base

Top: β-Hydroxy β-methylbutyric acid
Bottom: Calcium hydroxymethylbutyrate
Systematic (IUPAC) name
3-hydroxy-3-methylbutanoic acid
Clinical data
Routes of
administration		 oral (by mouth)
Legal status
Legal status
  • US: Unscheduled
Pharmacokinetic data
Metabolites HMB-CoA, HMG-CoA, mevalonate, cholesterol, acetoacetyl-CoA, acetyl-CoA
Biological half-life HMB-FA: 3 hours[1]
HMB-Ca: 2.5 hours[1]
Excretion Renal (10–40% excreted)[1]
Identifiers
CAS Number 625-08-1 YesY
ATC code none
PubChem CID 69362
ChemSpider 62571 YesY
UNII 3F752311CD YesY
ChEBI CHEBI:37084 YesY
Synonyms Conjugate acid form:
β-Hydroxyisovaleric acid
3-Hydroxyisovaleric acid
Conjugate base form:
Hydroxymethylbutyrate
Chemical data
Formula C5H10O3
Molar mass 118.131 g/mol
Physical data
Melting point −80 °C (−112 °F)
Boiling point 88 °C (190 °F) at 1 mmHg

β-Hydroxy β-methylbutyric acid (HMB) and its conjugate base β-hydroxy β-methylbutyrate (hydroxymethylbutyrate, HMB) is a dietary supplement that is marketed as a performance-enhancing agent and that "appears to speed recovery from high-intensity exercise".[1][2][3] Based upon a meta-analysis of seven randomized controlled trials, HMB supplementation helps preserve lean muscle mass in older adults and it may be useful for preventing muscle atrophy from bed rest.[4] It does not appear to significantly affect fat mass in older adults.[4] More research is needed to determine the precise effects on muscle strength and function in this age group.[4]

There appear to be no issues with safety (i.e., no adverse effects) from long-term use as a nutritional supplement in young or old individuals.[1][3][5]

HMB is a leucine metabolite produced in the body through oxidation of the ketoacid of leucine (α-ketoisocaproate).[1] It is found in various foods including grapefruit and catfish and is sold as a dietary supplement, sometimes as the calcium salt, calcium hydroxymethylbutyrate.[1][6]

As of 2015, HMB was not tested for or banned by any sporting organization in the United States or internationally.[3] A NCAA survey in 2013 found that 0.2% of student athletes used HMB as a dietary supplement;[3] however, the use of HMB among athletes appears to be increasing.[3]

Human metabolic pathway for HMB and isovaleryl-CoA, relative to leucine.[1] Of the two major pathways, leucine is mostly metabolized into isovaleryl-CoA, while only 5% or so is metabolized into HMB.[1]


References

  1. 1 2 3 4 5 6 7 8 9 Wilson JM, Fitschen PJ, Campbell B, Wilson GJ, Zanchi N, Taylor L, Wilborn C, Kalman DS, Stout JR, Hoffman JR, Ziegenfuss TN, Lopez HL, Kreider RB, Smith-Ryan AE, Antonio J (February 2013). "International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB)". J. Int. Soc. Sports. Nutr. 10 (1): 6. doi:10.1186/1550-2783-10-6. PMC 3568064. PMID 23374455.
  2. ↑ Portal S, Eliakim A, Nemet D, Halevy O, Zadik Z (July 2010). "Effect of HMB supplementation on body composition, fitness, hormonal profile and muscle damage indices". J. Pediatr. Endocrinol. Metab. 23 (7): 641–50. PMID 20857835.
  3. 1 2 3 4 5 Momaya A, Fawal M, Estes R (April 2015). "Performance-enhancing substances in sports: a review of the literature". Sports Med. 45 (4): 517–531. doi:10.1007/s40279-015-0308-9. PMID 25663250.
  4. 1 2 3 Wu H, Xia Y, Jiang J, Du H, Guo X, Liu X, Li C, Huang G, Niu K (September 2015). "Effect of beta-hydroxy-beta-methylbutyrate supplementation on muscle loss in older adults: a systematic review and meta-analysis". Arch. Gerontol. Geriatr. 61 (2): 168–175. doi:10.1016/j.archger.2015.06.020. PMID 26169182.
  5. ↑ Molfino A, Gioia G, Rossi Fanelli F, Muscaritoli M (December 2013). "Beta-hydroxy-beta-methylbutyrate supplementation in health and disease: a systematic review of randomized trials". Amino Acids 45 (6): 1273–1292. doi:10.1007/s00726-013-1592-z. PMID 24057808.
  6. ↑ 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.
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