Amino Acid
Calcium β-hydroxy β-methylbutyrate (HMB)
Also known as: HMB, β-hydroxy β-methylbutyrate, myHMB, Calcium HMB monohydrate
HMB is a metabolite of the branched-chain amino acid leucine that plays a role in muscle protein synthesis and breakdown prevention. It is investigated for its potential to support muscle mass, strength, and recovery in resistance training and aging populations.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Primary uses
- Muscle protein synthesis enhancement
- Attenuation of muscle protein breakdown
- Resistance training recovery support
- Age-related muscle loss (sarcopenia) management
- Athletic performance and strength gains
How it works
- Activates mTOR signaling pathway to promote muscle protein synthesis
- Inhibits proteasome and calpain-mediated muscle protein degradation
- Reduces inflammation and oxidative stress markers in muscle tissue
- May increase satellite cell activation for muscle fiber repair
Dosage
- Typical range
- 3,000–3,600 mg daily (divided into 2–3 doses, typically 1,000–1,200 mg per dose)
- Timing
- Distribute across meals; post-workout timing may offer marginal additional benefit when combined with resistance training
- With food
- With meals; may improve absorption and reduce GI upset
- Duration
- Effects typically emerge after 2–4 weeks of consistent supplementation. Long-term safety data support use for 12+ weeks. Discontinuation leads to gradual return to baseline within 2–4 weeks.
- Special populations
- Greatest benefit in older adults (65+), untrained individuals, and those recovering from illness or immobility. Benefits are additive to resistance training; minimal effect without exercise stimulus.
Forms
- Calcium HMB monohydrate· 70/100
- Free-acid HMB· 70/100
- Capsule· 70/100
- Tablet· 70/100
- Powder· 70/100
Safety
Common side effects
- Generally well-tolerated
- Mild GI upset (nausea, diarrhea) at high single doses; mitigated by dividing doses
- Occasional headache or dizziness reported (rare)
Contraindications
- No absolute contraindications at recommended doses
- Individuals with severe renal impairment should monitor metabolite levels (consult provider)
Evidence notes
Good-quality RCT evidence in resistance-trained and aging populations supports modest improvements in lean mass and strength. Effects are most pronounced in untrained individuals and older adults; benefits in trained athletes are smaller but consistent. Standard dose is 3 g/day.
Grade B: Some human trials support key claims; further confirmation needed.
Cited research for Calcium β-hydroxy β-methylbutyrate (HMB)
Clinical studies referenced across Formulate guides that mention calcium β-hydroxy β-methylbutyrate (hmb). Each links to the full study page with PubMed source + the guides that cite it.
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.