HMB (β-hydroxy β-methylbutyrate)
Recovery · Leucine metabolite
Tier B
What this is
Most useful when muscle loss is the concern (age-related sarcopenia, bed rest, training novices) rather than when maximizing gains in trained lifters. Wilson 2013 ISSN position stand is the standard reference. Free-acid form better absorbed than calcium HMB.
Mechanism
Downstream metabolite of leucine (~5% of leucine converts to HMB); upregulates mTORC1, downregulates proteasomal/autophagic protein breakdown; anti-catabolic more than anabolic
Dose & route
3 g/day PO divided (commonly 1 g 3x/day); calcium HMB or free-acid HMB
Citations
- https://pubmed.ncbi.nlm.nih.gov/23374455/
- https://pubmed.ncbi.nlm.nih.gov/23924954/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3568064/
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