Beta-hydroxy-beta-methylbutyrate free acid (HMB-FA)
What it is
The free acid form of HMB absorbs faster and reaches higher blood levels than the calcium salt. A 2024 meta-analysis found HMB-FA (3 g/day) significantly reduces muscle damage markers after resistance exercise and preserves lean mass during caloric restriction. ISSN position stand supports its use for trained athletes during overreaching phases and for older adults at risk of muscle loss.
Dose
3 g/day HMB free acid in 3 divided doses of 1 g; take 30–60 min before exercise
Time of day & tips
Split into 3 doses of 1 g spread throughout the day. Most effective during caloric restriction or intense training blocks. Less beneficial for beginners. Take the pre-exercise dose 30–60 min before training.
Compare or learn more
Compare with another supplement →
Browse by symptom →
Open the full interactive view →