HMB, commonly also known as β-Hydroxy β-Methylbutyrate or simply hydroxymethylbutyrate is a metabolite of the branched chain amino acid Leucine and is one of the primary compounds that support the anabolic properties of leucine. HMB is a well studied compound and it’s position as an ergogenic ingredient is coming back into popularity after experiencing a lull in the early 2000’s.
As previously mentioned, there has been plenty of research behind HMB as a supplement and it is considered one of the better supplements around. Some of the main benefits of HMB supplementation include:
- Improved Power Output – There is some evidence to suggest moderate increases in power output with HMB supplementation in resistance trainer men.1
- Increased Strength – HMB supplementation is able to support strength increases in resistance training of between 18.3% all the way up to over 204% over that of placebos.1,2
- Decreased Muscle Damage – Supplementation of HMB in resistance trained men is able to reduce markers of exercise induced muscle damage and also support recovery.3
- Increased Muscle Protein Synthesis – Again supplementation of HMB in resistance trained men resulted in an almost 252% greater increase in muscle mass than placebos.1
HMB & Weight Loss
There has been some speculation that HMB may be able to assist with fat and weight loss, however studies have been conflicting. In a study looking at resistance trained men, there was a decrease in fat mass, however the results were insignificant4. In another study5 looking at elite Judo athletes who were under calorie restriction, HMB further decreased fat mass over placebos. Overall there is some evidence to suggest HMB as a possible albeit expensive weight and fat loss support ingredient. The mechanisms aren’t fully understood, but it is believed that HMB helps to increase mitochondrial biogenesis (a part of the body responsible for energy production) and therefore increase fat oxidation6.
There has been a few studies looking at the safety of long term HMB supplementation. In one study, supplementation of 6g/day for a month had no adverse effects on cholesterol, hemoglobin, white blood cells, blood glucose, liver or kidney function7. Another 2 meta-analyses found that supplementation of HMB either by itself or with other amino acids also did not result in any adverse effects8,9. In general, the studies to date have not shown any adverse effects in young or old populations of varying degrees of fitness. There was one animal study that showed a decreased insulin sensitivity with one month of HMB supplementation10, however, this effect has not been seen in humans.
Does HMB Work?
From the countless positive ergogenic studies performed on this single ingredient, the answer would have to be yes. While there is a general consensus that leucine may be more effective and cost effective as a supplement in producing similar effects, HMB is still an excellent alternative for helping support the muscle building results you may be after. If you are considering taking HMB though, here are some tips on how to take it courtesy of the latest 2013 position stand on HMB by the International Society of Sports Nutrition:
- Whether you are trained or untrained, you can use HMB to help reduce muscular damage and go back into the gym faster.
- The ideal dose is 1g three times a day for an average period of a month.
- Try to take at least one dose before your workout with the other doses interspersed throughout the day. Most people tend to have it breakfast and lunch.
- Two forms of HMB are currently available, Calcium HMB and HMB Free Acid. The former has traditionally been used and studied, however HMB Free Acid is slowly gaining in popularity thanks to some new studies that have recently come out.
2. Dunsmore et al (2012), Effects of 12 weeks of beta-hydroxy-beta-methylbutyrate free acid gel supplementation on muscle mass, strength, and power in resistance trained individuals, J. Int. Soc. Sports Nutr. 9:Suppl. 1:P5
3. Wilson JM, et al. β-Hydroxy-β-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men. Br J Nutr. (2013)
4. Thomson JS, Watson PE, Rowlands DS. Effects of nine weeks of beta-hydroxy-beta- methylbutyrate supplementation on strength and body composition in resistance trained men. J Strength Cond Res. (2009)
5. Hunga W, Liub T-H, Chenc C-Y, Chang C-K. Effect of [beta]-hydroxy-[beta]-methylbutyrate Supplementation During Energy Restriction in Female Judo Athletes. J Exerc Sci Fitness.2010;8:50–53
6. Zemel RASMB: Role of β-hydroxy-β-methylbutyrate (HMB) in leucine stimulation of muscle mitochondrial biogenesis. FASEB J 2012, 26:251.6.
7. Gallagher PM, Carrithers JA, Godard MP, Schulze KE, Trappe SW: Beta-hydroxy-beta-methylbutyrate ingestion, part II: effects on hematology, hepatic and renal function. Med Sci Sports Exerc 2000, 32:2116-2119
8. Nissen S, Sharp RL, Panton L, Vukovich M, Trappe S, Fuller JC Jr: beta-hydroxy-beta-methylbutyrate (HMB) supplementation in humans is safe and may decrease cardiovascular risk factors. J Nutr 2000, 130:1937-1945.
9. Rathmacher JA, Nissen S, Panton L, Clark RH, Eubanks May P, Barber AE, D'Olimpio J, Abumrad NN: 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, 28:65-75
10. da Justa Pinheiro CH, et al.: Metabolic and functional effects of beta-hydroxy-beta-methylbutyrate (HMB) supplementation in skeletal muscle. Eur J Appl Physiol 2012, 112:2531-2537.img height=