HMB (Beta-Hydroxy Beta-Methylbutyrate)
Commonly used for
Weight LossMuscle & StrengthHealthy Aging
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What is it? / Overview
HMB is a metabolite of leucine that helps reduce muscle protein breakdown while supporting muscle protein synthesis. It appears most beneficial in older adults, during immobilization, or in people beginning resistance training.
How is it used? / Administration
Form: Calcium HMB (HMB-Ca) or free-acid HMB (HMB-FA)
Typical dose studied: 3 g/day split into 2–3 doses
Timing: Split through the day or 30–60 min before training
Greatest benefit when paired with resistance exercise. Less evidence in already well-trained athletes.
How well does it work? / Evidence
~ Moderate evidence
Who should avoid it?
Already taking it? Ensure adequate dietary protein first — HMB works best on top of sufficient protein intake.
Research & references
Wilkinson DJ et al. (2013). HMB and skeletal muscle protein metabolism. Journal of Physiology. Wu H et al. (2015). HMB and muscle loss in older adults meta-analysis. Archives of Gerontology and Geriatrics. Jäger R et al. (2017). ISSN Position Stand: Protein and Exercise. JISSN.
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