Overview
Research Article Title: International society of sports nutrition position stand: β-hydroxy-β-methylbutyrate (HMB)
Authors: John A. Rathmacher et al.
Published in: Journal of the International Society of Sports Nutrition
Date of Publication: 19 December 2024
Link to Article →
Summary
HMB has been studied in a variety of exercise training conditions to support the efficacy of HMB supplementation for enhancing recovery, lean body mass, muscle strength and power, and aerobic performance. This position stand serves as an update including a vast amount of new research published since the original International Society of Sports Nutrition (ISSN) position stand published in 2013.
ISSN Research Committee 12 Approved Points:
- Forms of HMB: HMB is a metabolite of leucine found naturally in humans and animals. It exists in two studied forms: HMB-Ca (calcium-bound) and HMB-FA (free acid).
- Safety: Long-term (up to one year) oral supplementation of both HMB-Ca and HMB-FA is considered safe in humans (1.5–3 grams/day).
- Glucose Metabolism: HMB has no negative effects on glucose tolerance or insulin sensitivity and may improve glucose metabolism in younger adults.
- Mechanism of Action: HMB enhances muscle protein synthesis and reduces muscle protein breakdown, primarily through mTORC1 activation, independent of the leucine-sensing pathway.
- Muscle Recovery: HMB may help reduce muscle damage and promote muscle recovery which can aid in muscle growth and repair. It has anti-inflammatory effects which can contribute to reducing muscle damage and soreness.
- Timing and Use: Taking HMB near exercise sessions can boost muscle protein synthesis and reduce inflammation. It shows benefits when taken both short- and long-term.
- Impact on Body Composition: Daily HMB (38 mg/kg body weight) combined with exercise may improve lean mass and reduce fat, especially when paired with resistance training and proper diet.
- Strength and Performance: HMB may improve strength and power in untrained individuals and have beneficial effects on athletic performance by improved recovery.
- Aerobic Performance: HMB can have a positive impact on aerobic performance in trained athletes but the mechanisms of the effects are unknown.
- Aging and Sarcopenia: HMB may help sedentary and older adults maintain muscle strength and quality. Combined with exercise, it may support treatment of age-associated sarcopenia under select conditions.
- Disuse Atrophy: HMB may reduce muscle loss during periods of inactivity (e.g., illness, injury), possibly through effects on mitochondrial function and lipid metabolism.
- Nutrient Synergy: HMB's effectiveness may be increased when combined with specific nutrients under certain conditions. Nutrients identified: probiotics, creatine monohydrate, amino acids, vitamin D, and protein (specifically soy).
Methodology
ISSN position stands are invited papers on key topics selected by ISSN editors and the Research Council to guide readers and the profession. A lead author or team conducts a comprehensive literature review, drafts a paper, and revises it based on expert feedback to form a consensus statement, which is then approved as the official ISSN position.
In this case, the authors performed a scoping review on HMB, analyzing over 750 articles from databases like PubMed, Google Scholar, and ResearchGate, with additional input from expert reviewers to ensure thorough coverage.
Why It Matters
HMB may be effective in countering muscle disuse atrophy during periods of inactivity due to illness or injury. It is a metabolite of the essential amino acid leucine that plays an anticatabolic role in muscle tissue. HMB may help reduce muscle damage and promote muscle recovery which can promote muscle growth and repair. HMB may also have anti-inflammatory effects, which can contribute to reducing muscle damage and soreness.
HMB has been studied in humans for nearly three decades with a range of dosages across a variety of populations and situations. HMB has been studied in a variety of exercise training conditions in both the young and the old, and these studies support the efficacy of HMB supplementation for enhancing recovery, lean body mass, muscle strength and power, and aerobic performance.
Limitations
Need for further research were identified within the various approved points in the position stand which include:
- Determine the role of chronic HMB supplementation on insulin sensitivity and glucose metabolism with consideration for age and sex.
- Comparison studies of HMB-Ca to HMB-FA to determine if there are any differences are needed.
- Women and older populations are needed to better understand the mode of action.
- Determine the optimal dosage and duration of supplementation to achieve improvements in aerobic performance.
- Potential synergistic effects of combining HMB with other supplements in an athletic population such as creatine monohydrate.
- Vitamin D status may impact the beneficial effects of HMB supplementation with age-associated sarcopenia, frailty and cachexia.
- Younger populations for HMB supplementation to support loss of muscle mass and strength because of disuse atrophy.
Final Thoughts
Adding in HMB supplementation for the non-exercising and aging population can provide benefits for muscle strength, functionality, and muscle quality along with countering muscle disuse atrophy during periods of inactivity from illness or injury/surgery.
Mend uses a licensed version of HMB. myHMB® is patented and has published clinical studies in orthopedic populations to substantiate the benefit in orthopedic populations at 3g per day.
If you are interested in learning more about our products and ways to utilize HMB into your surgical protocols, shoot us a message at support@mend.me.
MEND Products with myHMB®:
- Repair & Recover: Daily – 3g HMB per scoop. Citrus flavored with 16g whey protein.
- Repair & Recover: Surgery – 3g HMB per 2 scoops. Citrus flavored with 32g whey protein.
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Regenerate – 1.5g HMB per scoop. Dark Chocolate or Vanilla Malt flavors with 15g whey protein.
This article was written by Katie Frushour, MS, RD, CSSD, a dietitian at Mend.
