HMB (β-hydroxy β-methylbutyrate)
Nutrient:
β-hydroxy β-methylbutyrate (HMB)
Brief description
This is a metabolite of leucine – an amino acid which has the strongest ability to activate the ‘mTOR’ pathway (described as the main muscle synthesis pathway).
It can be found in foods such as grapefruit, fish, Greek yoghurt, soyabeans, chicken & beef.
Evidence base
Multiple systematic reviews found that supplementation improved muscle mass & function in older individuals, this reduced the risk of progression from sarcopenia and or frailty (1- 4).
The international Society for Sports and Exercise Nutrition have recently (2024) advised in combination with exercise, can improve lean muscle mass and or decrease fat mass, regardless of age, sex or training status(5)
Recommended serving & duration.
Most studies used a dose of 1.5-3g/day.
Studies also suggest splitting this evenly amongst meals e.g. 3 x 1g
Safety & tolerability:
Appears to be safe and well tolerated(7).
Please consult with your healthcare provider if you have any existing medical conditions, are pregnant or younger than 18 years old.
References:
Prado CM, Orsso CE, Pereira SL, Atherton PJ, Deutz NEP. Effects of β-hydroxy β-methylbutyrate (HMB) supplementation on muscle mass, function, and other outcomes in patients with cancer: a systematic review. J Cachexia Sarcopenia Muscle. 2022;13(3):1623-41.Oktaviana J, Zanker J, Vogrin S, Duque G. The Effect of β-hydroxy-β-methylbutyrate (HMB) on Sarcopenia and Functional Frailty in Older Persons: A Systematic Review. J Nutr Health Aging. 2019;23(2):145-50.Bear DE, Langan A, Dimidi E, Wandrag L, Harridge SDR, Hart N, et al. β-Hydroxy-β-methylbutyrate and its impact on skeletal muscle mass and physical function in clinical practice: a systematic review and meta-analysis. Am J Clin Nutr. 2019;109(4):1119-32.Lin Z, Zhao A, He J. Effect of β-hydroxy-β-methylbutyrate (HMB) on the Muscle Strength in the Elderly Population: A Meta-Analysis. Front Nutr. 2022;9:914866.Rathmacher JA, Pitchford LM, Stout JR, Townsend JR, Jäger R, Kreider RB, et al. International society of sports nutrition position stand: β-hydroxy-β-methylbutyrate (HMB). J Int Soc Sports Nutr. 2025;22(1):2434734.Rathmacher JA, Nissen S, Panton L, Clark RH, Eubanks May P, Barber AE, et al. Supplementation with a combination of beta-hydroxy-beta-methylbutyrate (HMB), arginine, and glutamine is safe and could improve hematological parameters. JPEN J Parenter Enteral Nutr. 2004;28(2):65-75.
