HMB is a metabolite of leucine, also available as a dietary supplement in market promoted to enhance your strength, muscles size and endurance. In this article, we shall learn about its benefits, recommended dose, methods to use and side-effects. We shall also read clinical studies on HMB regarding its effect on trained athletes and untrained healthy individuals.
What is HMB?
HMB (beta-hydroxy-beta-methyl-butyrate) is a naturally occurring metabolite of the amino acid leucine. In simple words, when our body metabolises leucine (a part of protein), HMB occurs as a by-product of this metabolism. HMB is not an essential nutrient.
Our body produces almost 250mg to 1000mg HMB every day, depends on our protein (specifically leucine) intake1. The whey protein supplement scoop that provides you 25g of Protein, also includes almost 2.7g leucine. HMB from leucine is almost 5% of its total metabolism. So, when your body metabolises 2.7g of leucine, it also produces almost 0.135g of HMB.
HMB Supplements in Market
Almost all major brands are manufacturing HMB supplements. In supplemental form, HMB is most often supplied as a calcium salt, written as “Calcium B-Hydroxy B-Methylbutyrate Monohydrate” or “Calcium HMB”; available in both capsules and powder forms.
For example, this is Optimum Nutrition HMB supplement. It has 90 capsules and each capsule contains 1000 mg of HMB in calcium salt form. Suggested serving is 1 capsule 3 times a day with protein rich meals. The price for 90 capsules is between Rs. 3500-4000 in Indian market.
HMB is available in blends also. For example, Cellucor Alpha Amino Ultimate. Most common ingredients blended with HMB are BCAAs, amino acids and creatine.
- Increase muscle mass
- Increase Strength
- Reduce post workout soreness and faster recovery
- Increase endurance performance
- HMB is slightly effective for untrained individuals, but in case of trained athletes, effects are negligible.
- HMB is not effective to improve body composition (lean muscle mass or fat free mass), in both trained and untrained athletes.
- HMB is effective to slightly improve lower body strength compare to upper body strength.
- HMB prevents or slows down muscle damage; works as a catabolic agent.
- Any dose higher than 3 grams/day does not seem to further increase any strength and lean muscle.
- Effect is same for males and females.
- Not effective on post workout muscle soreness.
- HMB can improve your endurance performance.
- HMB can prevent lactate formation.
A study5 examined the effect of different doses of HMB on skeletal muscle mass in untrained individuals, involving three doses of HMB (0, 1.5 and 3.0g/day) with two dietary protein intakes (117 and 175g/day) during a resistance training program for 3 weeks. This study shows a total strength increase in a dose responsive manner, also HMB prevents or slows muscle damage as well as partially preventing the increase in proteolysis associated with intense muscular work. No significant effect in body composition.
A placebo-controlled study4 examined the effect of HMB supplementation on aerobic (running) performance and body composition in active collage students. Students were randomly assigned to either 3 grams HMB/day or a placebo, for a 5 week period including 3 times interval training every week. Before and after intervention showed a significant difference, 8.4% for placebo group & 15.5% for HMB group, gains in maximal oxygen consumption. Regarding body composition, there was no significant difference. Authors concluded that HMB is effective to increase your aerobic performance.
A meta-analysis3 published by Journal of Strength & Conditioning Research in 2009, reviewed 9 major placebo-controlled studies on HMB, involving 394 participants both trained and untrained. In depth evaluation of all 9 studies showed that HMB has a very small effect in untrained individuals, but in case of trained individuals effects are unclear. Effect on body composition is also inconsequential.
A study6 was conducted by Philip M. Gallagher to examine the effect of HMB on strength and fat free mass. Three different doses (0, 38, or 76 mg/kg/day) HMB was given to thirty seven, untrained, collage aged persons including resistance training consisted of 10 different exercises performed 3 days per week for 8 weeks. If we calculate exact dose from (0, 38, or 76 mg/kg/day). then it becomes almost (0, 3 or 6 grams/day). The study resulted an improvement in strength of 32.5%, 43.5% and 45.5% for the 0, 3, and 6 grams/day doses, respectively. So we can see that a dose higher than 3g/day does not seem to further increase any strength and fat free mass. I am not interested in strength gains here because this study was partly funded by Metabolic Technologies, Inc which is an American life sciences company that sells dietary supplements and analytical services.
A 4 week short term study7 to investigate the roles of gender on the effects of HMB supplementation on strength and body composition, involving 39 men and 36 women on 3 grams/day HMB with three times resistance training every week, resulted that the effect of HMB supplementation is same for male and females.
A very short term study8 to understand the effect of HMB supplementation on muscle damage, involving 17 untrained persons on 40mg/kg of bodyweight/day HMB, concluded that HMB has not effect on muscle soreness and swelling following the damaging eccentric exercise.
A placebo-controlled study2 was conducted with regard to examine the effect of HMB on strength and body composition, involved the supplementation of 3 grams of HMB per day for 9 weeks by 22 resistance trained men. The effect of HMB on strength was measured by 1 repetition maximum method for lower body (leg extension) and upper body (bench press, bicep preacher curl), before and after the supplementation. 9 weeks supplementation resulted a combined average increase in strength by 1.6% only. When consider in isolation, lower body strength increased by 9.1% and upper body strength was inconclusive. We can say, HMB is more effective to increase lower body strength compare to upper body. If we talk about body composition, effects were negligible.
A 4-week study9 on trained 36 collegiate football players, supplementing 3 grams/day HMB with resistance training, resulted in no alterations in body composition or strength.
In a study, 8 endurance trained cyclists were supplemented 3 grams HMB everyday for 14 days to evaluate the onset of blood lactate accumulation, resulted that HMB promotes a decrease in lactate production, an increase in lactate removal or both.
How to Use HMB?
The effective dose for HMB is 3 grams per day. For best results, you should use as follows:
- 2 grams HMB, 45 minutes before workout, with protein shake or meal.
- 1 gram HMB, after workout, with protein shake or meal.
Safety or Side Effects
HMB is safe and well tolerated in all studies.
If you are a beginner and want to gain some muscles and strength, HMB can slightly help you. But I won’t recommend you this supplement because it very costly and very less effective. There is no need to spend too much money for minor gains. There are many other supplements like protein, BCAAs and creatine; which has low cost and much more effective.
If you have been training for more than 6 months and want to gain some lean muscles or strength; HMB will not work for you.
If you are an endurance athlete (running, swimming, cycling, football etc), and want to improve your performance, HMB may help you. I personally suggest you to use beta-alanine, creatine and caffeine for endurance. If you are already using these supplements, adding HMB in your stack can give you a boost.
If you are comparing Leucine and HMB, then leucine is better for muscle building and HMB is better for preventing muscle damage.
I suggest you to monitor your recommended protein intake. If you are taking enough protein in your diet; no need to think about HMB. Here is a simple formula to understand this concept. Protein > BCAA > Leucine > HMB.
- R, Gatnau, Zimmerman Dr, Nissen Sl, Wannemuehler M, and Ewan Rc. 1995. “Effects of Excess Dietary Leucine and Leucine Catabolites on Growth and Immune Responses in Weanling Pigs.” Journal of Animal Science 73 (1): 159–65. Microsoft Academic
- Thomson, Jasmine S, Patricia E Watson, and David S Rowlands. 2009. “Effects of Nine Weeks of β-Hydroxy-β- Methylbutyrate Supplementation on Strength and Body Composition in Resistance Trained Men.” Journal of Strength and Conditioning Research 23 (3): 827–35. Microsoft Academic
- Rowlands, David S, and Jasmine S Thomson. 2009. “Effects of β-Hydroxy-β-Methylbutyrate Supplementation During Resistance Training on Strength, Body Composition, and Muscle Damage in Trained and Untrained Young Men: A Meta-Analysis.” Journal of Strength and Conditioning Research 23 (3): 836–46. Microsoft Academic
- Lamboley, Cédric R.H., Donald Royer, and Isabelle J. Dionne. 2007. “Effects of β-Hydroxy-β-Methylbutyrate on Aerobic-Performance Components and Body Composition in College Students.” International Journal of Sport Nutrition and Exercise Metabolism 17 (1): 56–69. Microsoft Academic
- Nissen, S., R. Sharp, M. Ray, J. A. Rathmacher, D. Rice, J. C. Fuller, A. S. Connelly, and N. Abumrad. 1996. “Effect of Leucine Metabolite β-Hydroxy-β-Methylbutyrate on Muscle Metabolism during Resistance-Exercise Training.” Journal of Applied Physiology 81 (5): 2095–2104. Microsoft Academic
- Gallagher, Philip M., John A. Carrithers, Michael P. Godard, Kimberley E. Schulze, and Scott W. Trappe. 2000. “β-Hydroxy-β-Methylbutyrate Ingestion, Part I: Effects on Strength and Fat Free Mass.” Medicine and Science in Sports and Exercise 32 (12): 2109–15. Microsoft Academic
- Panton, Lynn B, John A Rathmacher, Shawn Baier, and Steven Nissen. 2000. “Nutritional Supplementation of the Leucine Metabolite β-Hydroxy-β-Methylbutyrate (HMB) during Resistance Training.” Nutrition 16 (9): 734–39. Microsoft Academic
- Paddon-Jones, Douglas, Andrew Keech, and David Jenkins. 2001. “Short-Term β-Hydroxy-β-Methylbutyrate Supplementation Does Not Reduce Symptoms of Eccentric Muscle Damage.” International Journal of Sport Nutrition and Exercise Metabolism 11 (4): 442–50. Microsoft Academic
- Ransone, Jack, Kerri Neighbors, Robert Lefavi, and Joseph Chromiak. 2003. “The Effect of β-Hydroxy β-Methylbutyrate on Muscular Strength and Body Composition in Collegiate Football Players.” Journal of Strength and Conditioning Research 17 (1): 34–39. Microsoft Academic
- Vukovich, Matthew D., and Geri D. Dreifort. 2001. “Effect of Beta-Hydroxy Beta-Methylbutyrate on the Onset of Blood Lactate Accumulation and V(O)(2) Peak in Endurance-Trained Cyclists.” NLM. Microsoft Academic