Amino Acid
Calcium β-hydroxy β-methylbutyrate monohydrate
Also known as: HMB, β-hydroxy β-methylbutyrate, beta-hydroxy beta-methylbutyrate, calcium HMB
HMB is a metabolite of the branched-chain amino acid leucine that may support muscle protein synthesis and reduce muscle breakdown during resistance training and caloric restriction. Research shows modest benefits for lean mass retention and strength gains, particularly in untrained or aging populations.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Every Calcium β-hydroxy β-methylbutyrate monohydrate product we have scored
| # | Product | Score | Per serving |
|---|---|---|---|
| 1 | NOW Foods HMB | 92 A | $0.44 |
| 2 | NOW Foods Sports Tablets, HMB With Vitamin D-3, 1,000 mg | 91 A | $0.38 |
| 3 | Double Wood HMB Supplement | 77 B+ | $0.33 |
Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.
Common questions
How much Calcium β-hydroxy β-methylbutyrate monohydrate should I take?
The typical range is 1.5-3 grams daily (divided into 2-3 doses). Benefits typically emerge after 2-4 weeks of consistent use; optimal duration unclear but studies extend to 12+ weeks
When should I take Calcium β-hydroxy β-methylbutyrate monohydrate?
Distributed throughout the day; around workouts may be optimal. May be taken with or without food; consistency more important than timing.
Which form of Calcium β-hydroxy β-methylbutyrate monohydrate is best?
Calcium HMB monohydrate capsules. Other forms in the catalog: Calcium HMB powder, Free acid HMB.
Is Calcium β-hydroxy β-methylbutyrate monohydrate safe?
Commonly reported: Generally well-tolerated, Rare reports of nausea or stomach upset at high doses.
Which Calcium β-hydroxy β-methylbutyrate monohydrate supplement scores highest?
NOW Foods HMB, at 92/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.
Primary uses
- Muscle protein synthesis support
- Lean mass preservation
- Strength and power development
- Recovery from resistance training
- Age-related muscle loss (sarcopenia)
How it works
- Inhibits protein degradation pathways (ubiquitin-proteasome system)
- Activates mTOR signaling for anabolic responses
- Modulates myostatin expression
- Reduces exercise-induced muscle damage markers
Dosage
- Typical range
- 1.5-3 grams daily (divided into 2-3 doses)
- Timing
- Distributed throughout the day; around workouts may be optimal
- With food
- May be taken with or without food; consistency more important than timing
- Duration
- Benefits typically emerge after 2-4 weeks of consistent use; optimal duration unclear but studies extend to 12+ weeks
- Special populations
- Appears safe and potentially beneficial for older adults and untrained individuals; limited evidence in elite/highly trained athletes
Forms
- Calcium HMB monohydrate capsules· 70/100
- Calcium HMB powder· 70/100
- Free acid HMB· 70/100
Safety
Common side effects
- Generally well-tolerated
- Rare reports of nausea or stomach upset at high doses
Contraindications
- No major contraindications identified
- Caution in individuals with severe kidney disease (metabolite clearance)
Products containing Calcium β-hydroxy β-methylbutyrate monohydrate
Top-scoring supplements in our catalog that list Calcium β-hydroxy β-methylbutyrate monohydrate on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Moderate evidence from multiple RCTs showing modest lean mass and strength gains in resistance-trained individuals, untrained persons, and aging populations. Effect sizes are generally small to moderate. Most robust evidence exists for untrained individuals and older adults; benefits in elite athletes less clear.
Grade B: Some human trials support key claims; further confirmation needed.
Cited research for Calcium β-hydroxy β-methylbutyrate monohydrate
Clinical studies referenced across Formulate guides that mention calcium β-hydroxy β-methylbutyrate monohydrate. Each links to the full study page with PubMed source + the guides that cite it.
Related in Amino Acid
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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.