Hydroxymethyl Butyrate (HMB)
Supplement Forms/Alternate Names:
- Beta-Hydroxy Beta-Methylbutyric Acid
Principal Proposed Uses
Other Proposed Uses
Technically "beta-hydroxy beta-methylbutyric acid," HMB is a chemical that occurs naturally in the body when the amino acid leucine breaks down. Leucine is found in particularly high concentrations in muscles. During athletic training, damage to the muscles leads to the breakdown of leucine as well as increased HMB levels. Evidence suggests that taking HMB supplements might signal the body to slow down the destruction of muscle tissue. 1 However, while promising, the research record at present is contradictory and marked by an absence of large studies.
SourcesHMB is not an essential nutrient, so there is no established requirement. HMB is found in small amounts in citrus fruit and catfish. To get a therapeutic dosage, however, you need to take a supplement in powder or pill form.
Therapeutic DosagesA typical therapeutic dosage of HMB is 3 g daily.Be careful not to confuse HMB with gamma hydroxybutyrate (GHB), a similar supplement. GHB can cause severe sedation, especially when combined with other sedating substances, such as alcohol or anti-anxiety drugs.
Therapeutic UsesAccording to some but not all of the small double-blind trials performed thus far, HMB may improve response to weight training. 2-9,21,24,25 One small double-blind, placebo-controlled trial found hints that HMB might help prevent muscle damage during prolonged exercise, thereby potentially enhancing recovery during athletic training ; 10 however, a follow-up study failed to find this benefit. 25 A very small study found evidence that HMB might improve aerobic exercise capacity. 26 Very weak evidence suggests that HMB might improve blood pressure and cholesterol levels. 18
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