Hydroxymethylbutyrate
Jan 2, 2025
Hydroxymethylbutyrate (HMB)
What Is It?
Beta-hydroxy-beta-methylbutyrate (HMB) is a metabolite of the amino acid leucine and is often used as a body building supplement to improve muscle strength while reducing protein breakdown.
How Does It Work in the Body?
HMB is a by-product of the amino acid leucine. Along with arginine and glutamine, these compounds prevent or reduce damage to muscle cells that occurs with intense exercise or in advanced cancers and AIDS.
What Is It Used for?
HMB can be used to prevent or reverse cancer- or HIV-related weight loss and weakness; however, there is limited research in these populations with conflicting results.
HMB is used historically to increase muscle mass. As mentioned before, HMB is an amino acid metabolite that aids in building muscle with halting protein breakdown. However, meta-analyses currently suggest that any benefits with HMB supplementation are small.
Precautions/Side Effects:
HMB appears to be generally safe and well tolerated, with little to no known side effects. HMB appears to be generally safe in standard doses of 3 g daily or less up to 1 year.
Evidence for and Against:
A study by Asjodi et al. demonstrated that hydroxymethylbutyrate supplementation can decrease serum creatine kinase and delay the onset of muscle soreness, while increasing the range of motion in certain joints. The use of HMB may also be able to repair cell wall damage during the activities.
Dosage:
The standard dose of HMB is a maximum of 3 g daily.
Interactions:
Studies indicate that the stimulating effect of HMB on mammalian target of rapamycin (mTOR) is reduced by rapamycin, an mTOR inhibitor. HMB's ability to reduce the effectiveness of these drugs is unknown.
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