HMB
amino acids
HMB (β-hydroxy β-methylbutyrate) is a metabolite of the branched-chain amino acid leucine that supports muscle protein synthesis and recovery. It is primarily used by athletes and older adults to preserve lean muscle mass and reduce exercise-induced muscle breakdown.
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Benefits
Dosage
Typical Dose
2-3g daily in divided doses
Upper Limit
3g daily
Timing
Distribute throughout the day, particularly around training
Forms & Bioavailability
HMB Monohydrate
Standard form with good absorption; typically dosed at 2-3g daily
HMB-FA (Free Acid)
Faster absorption than monohydrate; may be effective at lower doses (1g daily)
Side Effects
Interactions
Research Summary
Research demonstrates HMB's efficacy in reducing muscle protein breakdown during periods of caloric deficit or immobilisation, particularly in older adults and untrained individuals. Benefits are most pronounced when combined with resistance training. Effects on muscle hypertrophy in trained athletes are modest and may require longer duration studies for definitive conclusions.
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The Bottom Line on HMB
HMB is moderately researched with promising but sometimes mixed evidence.It is most commonly used for muscle protein synthesis and reduced muscle breakdown. As with any supplement, individual results vary. Start with the lower end of the dosage range and assess for 4-8 weeks before adjusting.
About Our Research
This profile is compiled from peer-reviewed research published on PubMed, the NIH Office of Dietary Supplements, and established nutritional science databases. Dosages reflect clinically-studied amounts from human trials where available. We update profiles as new research emerges. This is not medical advice — consult a healthcare professional before supplementing.
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