HMB : Is This Descendant Of The Mighty Leucine Overrated Or Overlooked?

Meet Beta- hydroxyl- beta- methylbutyrate, but you can call it HMB! This long winded nutritional component is what’s known as a metabolite of the anti- catabolic Branched Chain Amino Acid (BCAA) Leucine. You can obtain HMB from catfish, breast milk and citrus fruits…so realistically just fruit then, because who really consumes any of the other two (disgusted face). Consequently, should you wish to ingest the requisite amounts of HMB in order to reap a potential ergogenic effect, then you might want to consider a nutritional supplement.

HMB product range

Should you consider HMB?

When considering if a supplement is suited to your needs you may wish to think about the following: What does it do, how does it do it, and does it work? Bare in mind that your body can produce HMB by itself via Leucine, you see HMB is what’s known as a metabolite of Leucine meaning it is a product of Leucine. So when Leucine is broken down for muscle protein synthesis you’re left with HMB, which leads on nicely to why you might consider supplementing with it. Supplementation may be of benefit because the amount produced in your body alone is unlikely to be adequate to induce an ergogenic, or performance enhancing effect.


Can you trust HMB?

The validity of a supplement depends on the validity of the research behind it. When assessing what a supplement can do for you, it’s wise to refer to peer reviewed research or nutrition articles that reference such research. If the research is non- existent or doesn’t have a definitive answer, then think long and hard as to whether you want to invest your time and money on the supplement. However, sometimes logical rationale can be employed when making a decision, and in HMB’s case the logic is sound. There have been no adverse side effects documented in any of the referenced research, so HMB is deemed to be safe.


What is HMB supposed to do?

Considering HMB is a derivative of Leucine, which is widely accepted (according to research) to be one of the most anabolic of all essential amino acids, it stands to reason that it may promote muscle repair and resistance to damage. In addition to HMB’s anabolic properties, it is also thought to support ventilatory thresholds as well as increasing time to exhaustion (although the mechanism behind the latter is less clear). So theoretically HMB can support muscle protein synthesis, recovery, and indirectly strength (Llewellyn, 2009). This said, research by Greenwood, Kalman & Antonio, (2008) suggest that HMB’s effects may be more apparent in relatively untrained people compared to those with a higher level of fitness to begin with, so its purported benefit may well be subjective (depends on the individual).


How does it work?

Theories behind HMB’s ergogenic effects include activity via the stimulation of MAPK and P13K pathways, as well as its reported capacity to raise IGF-1 mRNA levels. In simpler terms, these pathways and hormones are precursors to muscle protein synthesis (muscle growth), and minimising catabolism (muscle breakdown), so if they are up- regulated, then so might your muscle growth and strength gains too. Recent research by Robinson, Stout, Miramonti et al. (2014) suggests that HMB’s potential to improve aerobic power and metabolic thresholds in athletes also performing High Intensity Interval Training (HIIT) may be down to its potential to increase fatty acid oxidation, up- regulating energy metabolising enzymes such as adenosine monophosphate kinase, as well as increasing the density and blood flow of mitochondria (your bodies energy manufacturing factories). The result of all this is an increase in ATP and glycogen content within the muscle, which may translate as improved performance.


How much?

In order to invoke these desired effects the current evidence base suggests a dosage of approx 3g HMB a day. HMB comes in capsule and powder form, whilst also being added to some protein bars.


Overrated or Overlooked?

As a consumer you are obligated to question the reputability and validity of a supplement, we wouldn’t expect any less. As a retailer and hub of information it is our obligation to offer impartial and honest appraisals of the products we sell. So is HMB overrated... no, is it overlooked... possibly, it is my opinion that HMB simply isn’t understood anywhere near as well as it should be! Being the ‘understudy’ of leucine so to speak, means HMB’s ergogenic (performance enhancing) capacity is still relatively unexplored. Yes there is research out there, but in order to really validate a products place in sports nutrition it needs to stand a fair and unbiased trial. This trial should come in the form of a meta- analysis whereby all research surrounding HMB is gathered and critiqued in order to come out with an overwhelming consensus on its benefit. As yet HMB awaits its hearing, so in a roundabout way I suppose it is somewhat overlooked. In light of existing evidence, I feel HMB may offer some benefit to strength, muscle repair, VO2 peak, and overall energy delivery during exercise if coupled with a structured training regime and if the consumer still has plenty of room for athletic improvement.



Greenwood, M., Kalman, D, S. & Antonio, J. (2008). Nutritional Supplements in Sports and Exercise. HMB. NJ: Humana Press

Llewellyn, W. (2009). Sport Supplement Reference Guide. HMB. FL: Molecular Nutrition

Robinson, E, H., Stout, J, R., Miramonti, A, A., Fukuda, D, H., Wang, R. et al. (2014). High-intensity interval training and β-hydroxy-β-methylbutyric free acid improves aerobic power and metabolic thresholds. Journal of the international society of sports nutrition. 11: 16

Wilson, J, M., Fitschen, P, J., Campbell, B., Wilson, G, J., & Zanchi, N. (2013). International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB). Journal of the international society of sports nutrition. Retrieved 30th June, 2014, from








About the Author

Job Role Qualified Dietitian and Sports Nutritionist Qualifications BSc (Hons) Sports Science | BSc (Hons) Dietetics Tom has always participated in sport both recreationally and competitively which led to an unquenchable thirst for information on anything health, nutrition and fitness. After leaving school Tom went on to play for a football academy during which time he studied Sport and Exercise Science. From here he went on to study a BSc (Hons) Sport Science at UEA followed by his second BSc (Hons) degree, this time at the University of Hertfordshire studying Dietetics. Tom has worked in the fitness, educational and clinical nutrition industry starting out at David Lloyd Health and Leisure Clubs. He then went on to work as a Dietitian (RD) in the NHS, during which time he conducted clinics for healthy eating, weight loss and weight gain, as well as specialised consultations on Diabetes, IBS and Coeliac disease to name a few. He has vast amounts of experience at devising diet plans and supplement regimens, as well as working in the community with schools and competitive athletes. As Head Nutritionist and Supplement expert at Discount Supplements Tom is here to provide current and evidence based health and nutrition information to help you reach your health and fitness goals!
Post a Comment

Please wait...