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.
Every Calcium β-hydroxy β-methylbutyrate (HMB) 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 (HMB) should I take?
The typical range is 3,000–3,600 mg daily (divided into 2–3 doses, typically 1,000–1,200 mg per dose). 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.
When should I take Calcium β-hydroxy β-methylbutyrate (HMB)?
Distribute across meals; post-workout timing may offer marginal additional benefit when combined with resistance training. With meals; may improve absorption and reduce GI upset.
Which form of Calcium β-hydroxy β-methylbutyrate (HMB) is best?
Calcium HMB monohydrate. Other forms in the catalog: Free-acid HMB, Capsule, Tablet, Powder.
Is Calcium β-hydroxy β-methylbutyrate (HMB) safe?
Commonly reported: Generally well-tolerated, Mild GI upset (nausea, diarrhea) at high single doses; mitigated by dividing doses, Occasional headache or dizziness reported (rare).
Which Calcium β-hydroxy β-methylbutyrate (HMB) 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 enhancement
- Attenuation of muscle protein breakdown
- Resistance training recovery support
- Age-related muscle loss (sarcopenia) management
- Athletic performance and strength gains
What systematic reviews concluded
Outcomes that systematic reviews of Calcium β-hydroxy β-methylbutyrate (HMB) reached a verdict on: 4 with a benefit, 3 with no effect, 2 unclear. Each is quoted from a review and linked to it on PubMed. How these were read.
Reviews found a benefit (4)
“evidence of a beneficial effect of HMB supplementation was found in four of four studies for muscle mass, two of two for muscle function, three of three for hospitalization, and five of seven for survival.” PMID 35301826 · 2 reviews
“HMB (3 g·d -1 ) ingestion during 2-12 weeks significantly improves endurance performance and V̇O 2 max .” PMID 38090973
“The exceptions were β-hydroxy β-methylbutyrate and betaine, which can be considered effective for male athletes.” PMID 37697053
“The current evidence revealed a time-dependent effect of HMB in reducing LDH and CK serum levels among adults.” PMID 29676656
Reviews found no effect (3)
“The combination of HMB supplementation and resistance training does not improve body composition or muscle strength in adults aged 50 years and older.” PMID 41934514 · 2 reviews
“no beneficial effects of HMB on quality of life or body weight was found in two of four and three of five studies, respectively.” PMID 35301826
“Two other studies investigated a combination of arginine, glutamine, and β-hydroxy-β-methylbutyrate; however, they did not yield significant results, and one study favored a hyperproteic formula instead of a hyperproteic formula with arginine.” PMID 38696907
Not enough to say: muscle strength; physical performance.
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)
Products containing Calcium β-hydroxy β-methylbutyrate (HMB)
Top-scoring supplements in our catalog that list Calcium β-hydroxy β-methylbutyrate (HMB) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
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.
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.