Wilson, J.M., P.J. Fitschen, B. Campbell, G.J. Wilson, N. Zanchi, L. Taylor, C. Wilborn, D.S. Kalman, J.R. Stout, J.R. Hoffman, T.N. Ziegenfuss, H.L. Lopez, R.B. Kreider, A.E. Smith-Ryan, and J. Antonio, 2013 International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB), J. Int. Soc. Sports Nutr. 10:6
This publication is the International Society of Sports Nutrition position stand on the efficacy of HMB use in sports nutrition and combines a comprehensive review of HMB with the official position of the ISSN on HMB use. The position statements included in this paper were reviewed and approved by the Research Committee of the ISSN. Based upon this comprehensive review of HMB literature, the primary position statements were that HMB enhances muscle recovery by attenuating muscle damage; HMB increases muscle hypertrophy, strength, and power in trained and untrained populations when the appropriate exercise protocol is applied; HMB efficacy is manifested in young and old; and HMB is safe to consume.
Portal S., Z. Zadik, J. Rabinowitz, R. Pilz-Burstein, D. Adler-Portal, Y. Meckel, D. Cooper, A. Eliakim, and D. Nemet, 2011 The effect of HMB supplementation on body composition, fitness, hormonal and inflammatory mediators in elite adolescent volleyball players: a prospective randomized, E. J. Appl. Physiol. 111:2261-2269
This randomized, double-blind, placebo-controlled study examined HMB supplementation in young male and female elite volleyball players for 7 wks. HMB supplementation resulted in improved body composition and significantly increased strength, while also decreasing fat mass percentage. HMB supplementation also increased peak and mean anaerobic power. No changes in hormones or inflammatory mediators were seen in this study.
Fuller, Jr., J.C., S. Baier, P. Flakoll, S.L. Nissen, N.N. Abumrad, and J.A. Rathmacher., 2011 Vitamin D status affects strength gains in older adults supplemented with a combination of β-hydroxy-β-methylbutyrate, arginine, and lysine: A cohort study., JPEN 35:757-762 This year-long retrospective study in elderly adults demonstrated that a nutrient mixture of HMB, arginine, and lysine alone was effective in improving body composition regardless of vitamin D status, but accompanying strength increases were observed only when participants also had adequate vitamin D status indicating a synergistic effect between the HMB, arginine, and lysine and vitamin D.
Rowlands, D.S., and J.S. Thomson, 2009 Effects of beta-hydroxy-beta-methylbutyrate supplementation during resistance training on strength, body composition, and muscle damage in trained and untrained young men: a meta-analysis, J. Strength Cond. Res. 23:836-846
This recent meta-analysis was conducted on the effects of HMB in younger men participating in resistance-training programs. The data were broken into trained and untrained subject groups. The authors concluded that HMB supplementation resulted in clear overall increases in strength in men entering a resistance training program, but that the benefit of HMB in trained athletes was smaller.
Thomson, J.S., P.E. Watson, and D.S. Rowlands, 2009 Effects of nine weeks of beta-hydroxy-beta- methylbutyrate supplementation on strength and body composition in resistance trained men, J. Strength Cond. Res. 23:827-835
In this 9-week, randomized, double-blind, placebo-controlled study, HMB improved body composition and decreased fat mass which resulted in a substantial increase in lower body strength.
Baier, S., D. Johannsen, N. Abumrad, J.A. Rathmacher, S. Nissen, and P. Flakoll, 2009 Year-long changes in protein metabolism in elderly men and women supplemented with a nutrition cocktail of beta-hydroxy-beta-methylbutyrate (HMB), L-arginine, and L-lysine, JPEN 33:71-82 In this year-long, double-blind, placebo-controlled study in the elderly, daily supplementation with HMB, arginine, and lysine resulted in improved body composition and protein turnover.
Kraemer W.J., D.L. Hatfield, J.S. Volek, M.S. Fragala, J.L. Vingren, J.M. Anderson, B.A. Spiering, G.A. Thomas, J.Y. Ho, E.E. Quann, M. Izquierdo, K. Hakkinen, and C.M. Maresh, 2009 Effects of amino acids supplement on physiological adaptations to resistance training, Med. & Sci. in Sports & Exerc. 41:1111-1121
This randomized, double-blind, placebo-controlled study tested the effects of EAS Muscle Armor® (main ingredients HMB, arginine and glutamine) in resistance-training men in a 12 week study. This study showed that supplementation with Muscle Armor® improved the effects of the training on improving body composition and increasing fat loss compared with placebo supplementation. Muscle Armor® beneficially improved hormonal markers associated with intense resistance exercise and improvement in body composition. Muscle Armor® also resulted in greater increases in strength, power, thigh circumference, and decreased indicators of muscle damage.
Wilson, G.J., J.M. Wilson, and A.H. Manninen, 2008 Effects of beta-hydroxy-beta-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: A review, Nutr. Metab. (Lond) 5:1 This independent, peer-reviewed paper discusses the critical details of HMB studies and the variables affecting the results of these studies. Included is a review of the current research showing how HMB works (metabolic mechanisms). This paper concludes that collectively there is not only clinical data, but also mechanistic data supporting HMB's effect on improving body composition and increasing muscle strength.
O’Connor, D.M. and M.J. Crowe, 2007 Effects of six weeks of ß-hydroxy-ß-methylbutyrate (HMB) and HMB/creatine supplementation on strength, power, and anthropometry of highly trained athletes, J. Strength Cond. Res. 21:419-423
Subjects’ ethical backgrounds prevented this study from being conducted as a double-blind, placebo-controlled study; however, a placebo treatment was utilized. Using skin-fold data reported in this paper, results demonstrated a numerical improvement in body composition with HMB supplementation. This calculation was however not reported in the paper.
Kuhls, D.A., J.A. Rathmacher, M.D. Musngi, D.A. Frisch, J. Nielson, A. Barber, A.D. MacIntyre, J.E. Coates, and J.J. Fildes, 2007 ß-Hydroxy-ß-methylbutyrate (HMB) supplementation in critically ill trauma patients, J. Trauma Inj. Infect. & Crit. Care 62:125-131 This placebo-controlled, double-blind clinical study of HMB in critically injured patients suggests that HMB can improve nitrogen balance in severely injured trauma patients.
Nissen, S.L., 2007 ß-Hydroxy-ß-methylbutyrate. In J.A. Driskell (Ed.) Sports Nutrition: Fats and Proteins, Boca Raton: CRC Press 12:221-241 This chapter in the CRC series of desk references for professional nutritionists and trainers discusses the origins, mechanisms, uses, safety, and results of HMB supplementation in both healthy individuals and those experiencing unwanted muscle loss.
Flakoll, P., R. Sharp, S. Baier, D. Levenhagen, C. Carr, and S. Nissen, 2004 Effect of ß-hydroxy-ß-methylbutyrate (HMB), arginine, and lysine supplementation on strength, functionality, body composition, and protein metabolism in elderly women, Nutrition 20:445-451 In two independent double-blind, randomized, placebo-controlled clinical studies in elderly women, data from both of the studies studies demonstrate that a nutritional mixture of HMB, arginine, and lysine can enhance whole body protein synthesis and improve functionality in elderly women.
Ransone, J., K. Neighbors, R. LeFavi, and J. Chromiak, 2003 The effect of ß-hydroxy-ß-methylbutyrate (HMB) on muscular strength and body composition in collegiate football players, J. Strength Cond. Res. 17:34-39 This study was a double-blind, randomized crossover study in 35 training collegiate football players. This study was performed with highly trained athletes undergoing an intense training program. Although this study failed to show significant differences, HMB-supplemented subjects showed improved body composition and a decrease in body fat.
Nissen, S. and R. Sharp, 2003 The efficacy of dietary supplements in accentuating the muscle mass and strength gains achieved with resistance exercise: A meta-analysis, J. Appl. Physiol. 94:651-659 This meta-analysis of dietary supplements used to improve body composition and strength with resistance-exercise training shows that few supplements used as ergogenic aids have two or more peer-reviewed studies. Only HMB and creatine have been shown to significantly improve body compositin and increase strength gains with exercise.
Vukovich, M.D., N.B. Stubbs and R.M. Bohlken, 2001 Body composition in 70-year-old adults responds to dietary ß-hydroxy-ß-methylbutyrate (HMB) similarly to that of young adults, J. Nutr. 131:2049-2052 This paper reports a double-blind, randomized study in elderly men and women participating in a weight training exercise program. In this 8-week study in older adults, HMB tended to increase muscle strength and improve body composition while significantly increasing fat loss.
Jówko, E., P. Ostaszewski, M. Jank, J. Sacharuk, A. Zieniewicz, J. Wilczak, and S. Nissen, 2001 Creatine and ß-hydroxy-ß-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight training program, Nutrition 17:558-566 This study reported the effects of HMB and creatine in a double-blind, randomized study in weight-training males. The results showed that HMB combined with creatine supplementation results in even greater strength gains and improvements in body composition than either HMB or creatine supplementation alone.
Slater, G., D. Jenkins, P. Logan, H. Lee, M. Vukovich, J.A. Rathmacher and A.G. Hahn, 2001 ß-Hydroxy-ß-methylbutyrate (HMB) supplementation does not affect changes in strength or body composition during resistance training in trained men, Int. J. Sport Nutr. & Exer. Met. 11:384-396 In this double-blind, randomized study in trained male athletes undergoing a weight-training program, HMB supplementation numerically increased strength and improved body composition; however, the gains were not significantly greater than those of the placebo group.
Gallagher, P.M., J.A. Carrithers, M.P. Godard, K.E. Schulze, and S.W. Trappe, 2000 ß-Hydroxy-ß-methylbutyrate (HMB) ingestion, Part I: effects on strength and fat free mass, Med. & Sci. in Sports & Exer. 32:2109-2115 In this double-blind, randomized study with male weightlifters, either three or six grams of HMB were consumed per day. HMB improved body composition, increased peak muscle torques, and decreased plasma CPK after resistance training with no added benefit seen from consuming the higher level.
Panton, L.B., J.A. Rathmacher, S. Baier, and S. Nissen, 2000 Nutritional supplementation of the leucine metabolite ß-hydroxy-ß-methylbutyrate (HMB) during resistance training, Nutrition 16:734-739 Two double-blind randomized studies including males and females and trained and untrained weightlifters. Both studies showed that regardless of gender or prior training, HMB increases strength and minimizes muscle damage when combined with a four-week resistance-training program.
Kreider, R.B., M. Ferreira, M. Wilson, and A.L. Almada, 1999 Effects of calcium ß-hydroxy-ß-methylbutyrate (HMB) supplementation during resistance training on markers of catabolism, body composition, and strength, Int. J. Sports Med. 20:503-509 This paper describes a four-week, randomized, placebo-controlled study of 40 experienced resistance-trained males. In this study the trained athletes consumed either three or six grams of HMB per day. While not statistically significant, HMB consumption resulted in improved body composition and numerically greater strength gains.
Nissen, S., R. Sharp, M. Ray, J.A. Rathmacher, D. Rice, J.C. Fuller, Jr., A.S. Connelly and N. Abumrad, 1996 Effect of the leucine metabolite ß-hydroxy-ß-methylbutyrate (HMB) on muscle metabolism during resistance-exercise training, J. Appl. Physiol. 81:2095-2104 Two double-blind, placebo-controlled, randomized studies were conducted in weight training males. In these separate studies, one for three weeks and one for seven weeks, it was found that supplementing three grams of HMB to exercising humans improved body composition, increased strength, and reduced muscle damage.
Lamboley, C.R., D. Royer, and I.J. Dionne, 2007 Effects of ß-hydroxy-ß-methylbutyrate (HMB) on aerobic performance components and body composition in college students, Int. J. Sport Nutr. Exerc. Metab. 17:56-69 In this placebo-controlled study in interval-training college students, HMB supplementation was shown to significantly increase maximal oxygen consumption and respiratory compensation point.
Vukovich, M.D. and G.D. Dreifort, 2001 The effect of ß-hydroxy-ß-methylbutyrate (HMB) on VO2 peak and lactate threshold in endurance-trained cyclists, J. Strength and Conditioning Res. 15:491-497 This double-blind switchback study with HMB, leucine, and placebo showed that HMB supplementation increased the cyclists endurance as measured by VO2 peak and lactate threshold.
Knitter, A., L. Panton, J.A. Rathmacher, A. Peterson, and R. Sharp, 2000 Effects of ß-hydroxy-ß-methylbutyrate (HMB) on muscle damage after a prolonged run, J. Appl. Physiol. 89:1340-1344 This double-blind randomized study in male and female runners showed that HMB reduced muscle damage after a prolonged run. Decreasing the amount of muscle damage caused by running may decrease the DOMS soreness many long-distance runners experience.
Baxter, J.H., J.L. Carlos, J. Thurmond, R.N. Rehani, J. Bultman, and D. Frost, 2005 Dietary toxicity of calcium ß-hydroxy-ß-methylbutyrate (CaHMB), Food & Chem. Toxicology 43:1731-1741 A toxicity study in rats fed up to five percent HMB in the diet was conducted. The data showed that HMB at five percent of the diet can be considered the NOAEL (no observed adverse effect level). The intakes were 3.49 and 4.16 g HMB/kg body weight per day in male and female rats, respectively. (Like a normal human consuming about 300 g per day)
Gallagher, P.M., J.A. Carrithers, M.P. Godard, K.E. Schulze, and S.W. Trappe, 2000 ß-Hydroxy-ß-methylbutyrate (HMB) ingestion, Part II: effects on hematology, hepatic and renal function, Med. & Sci. in Sports & Exer. 32:2116-2119 In this eight-week double-blind, randomized study with male weightlifters consuming up to six grams of HMB per day was shown to have no adverse effects on measures of hematology and hepatic and renal function.
Nissen, S., R.L. Sharp, L. Panton, M. Vukovich, S. Trappe, and J.C. Fuller, Jr., 2000 ß-Hydroxy-ß-methylbutyrate (HMB) supplementation in humans is safe and may decrease cardiovascular risk factors, J. Nutr. 130:1937-1945 This study reported a summary of safety data from nine double-blind, placebo-controlled, randomized clinical trials including both men and women and young and elderly adults. HMB supplementation was shown to have no adverse or untoward effects. HMB supplementation was also shown to have positive effects on LDL cholesterol (-7.3 percent) and systolic blood pressure (-4.4 mm Hg).
Wilkinson, D.J., T. Hossain, D. Hill, B.E. Phillips, H. Crossland, J. Williams, P. Loughna, T.A. Churchward-Venne, L. Breen, S.M. Phillips, T. Etheridge, J.A. Rathmacher, K. Smith, N.J. Szewczyk, and P.J. Atherton, 2013 Effects of leucine and its metabolite, β-hydroxy-β-methylbutyrate (HMB) on human skeletal muscle protein metabolism, J. Physiol. FV:1-35
Skeletal muscle protein turnover was measured in healthy young men in response to an oral dose of either 2.4 g of HMB in free acid form or 3.4 g of leucine. While both HMB and leucine stimulated muscle protein synthesis, HMB was also shown to attenuate muscle protein breakdown (-57%). The authors concluded that HMB induces anabolic effects in skeletal muscle that are distinct and/or additive to the effects of leucine.
Aversa, Z., N. Alamdari, E. Castillero, M. Muscaritoli, F.R. Fanelli, and P.O. Hassegren, 2012 β-Hydroxy-β-methylbutyrate (HMB) prevents dexamethasone-induced myotube atrophy, Biochem. Biophysical Res. Comm. 423:739-743
This study used a model cell culture system that represents what happens in an animal or human. Glucocorticoids, such as dexamethasone used in this study, cause increased muscle protein degradation and decreased protein synthesis which result in a loss of muscle. HMB attenuated the negative effects of dexamethasone on protein degradation and protein synthesis and thus prevented the muscle loss.
Wilson, J.M., S.C. Grant, S.R. Lee, I.S. Masad, Y.M. Park, P.C. Henning, J.R. Stout, J.P. Loenneke, B.H. Arjmandi, L.B. Panton, and J.S. Kim, 2012 Beta-hydroxy-beta-methyl-butyrate blunts negative age-related changes in body composition, functionality and myofiber dimensions in rats, J. Int. Soc. Sports Nutr. 9:18 In a study using sedentary rats of multiple age groups, from young to old, HMB supplementation was shown to maintain muscle mass as the rats aged. HMB simultaneously decreased fat mass in older rats. Thus, HMB supplementation may be useful in blunting the effects of sarcopenia (muscle loss with aging) in humans, even without a stimulus such as regular exercise.
Pinheiro, C.H., F. Gerlinger-Romero, L. Guimarães-Ferreira, A.L. de Souza-Jr, K.F. Vitzel, R.T. Nachbar, M.T. Nunes, and R. Curi, 2012 Metabolic and functional effects of beta-hydroxy-beta-methylbutyrate (HMB) supplementation in skeletal muscle., Eur. J. Appl. Physiol. 112:2531-2537
In this study utilizing rats, HMB was shown to improve muscle tetonic force after 4 weeks of oral supplementation. HMB also decreased muscle fatigue as measured by muscle tension developed over successive contractions. Additionally, HMB increased glycogen, ATP, and citrate synthase activity in these muscles which may have been why the HMB-supplemented rats had increased tetonic force and fatigue resistance.
Kornasio, R., I. Riederer, G. Butler-Browne, V. Mouly, Z. Uni, and O. Halevy, 2009 β-Hydroxy-β-methylbutyrate (HMB) stimulates myogenic cell proliferation, differentiation and survival via the MAPK/ERK and PI3K/Akt pathways, Biochim. Biophys. Acta 1793:755-763
This in vitro study of HMB on muscle cells showed that HMB affects myoblast differentiation and survival similar to IGF-1 and suggests that HMB has a positive role in preventing muscle wasting.
Russell, S.T., and M.J. Tisdale, 2009 Mechanism of attenuation by β-hydroxy-β-methylbutyrate of muscle protein degradation induced by lipopolysaccharide, Mol. Cell. Biochem. 330:171-179
Lipopolysaccharide (LPS) was used to simulate an endotoxemia model of muscle wasting in cultured muscle cells. HMB was shown to attenuate the LPS-induced protein degradation. HMB attenuated the activation of caspase-3/-8, activation of dsRNA-dependant protein kinase, and production of reactive oxygen species. This study further defined the mechanism whereby HMB may attenuate protein degradation in muscle wasting.
Wilson, J.M., J. Kim, S. Lee, J.A. Rathmacher, B. Dalmau, J.D. Kingsley, H. Koch, A.H. Manninen, R. Saadat, and L.B. Panton, 2009 Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage, Nutrition & Metabolism 6:6
HMB supplementation was given either pre- (60 min to allow blood levels to increase) or post-exercise to college-aged men performing acute isometric exercise by maximal voluntary contraction of the quadriceps and hamstrings. Taking HMB pre-exercise prevented an increase in lactate dehydrogenase (LDH), an indicator of muscle damage. Therefore this study indicated there was an advantage to taking HMB pre-exercise.
Holecek, M., T. Muthny, M. Kovarik, and L. Sispera, 2009 Effect of beta-hydroxy-beta-methylbutyrate (HMB) on protein metabolism in whole body and in selected tissues, Food Chem. Toxicol. 47:255-259 In this study tissue as well as whole body protein turnover was studied in rats after HMB administration. This study demonstrated that HMB inhibits proteasome dependent proteolysis in skeletal muscle and decreases whole body protein turnover.
Nunes, E.A., D. Kuczera, G.A. Brito, S.J. Bonatto, R.K. Yamazaki, R.A. Tanhoffer, R.C. Mund, M. Kryczyk, and L.C. Fernandes, 2008 β-Hydroxy-β-methylbutyrate supplementation reduces tumor growth and tumor cell proliferation ex vivo and prevents cachexia in Walker 256 tumor-bearing rats by modifying nuclear factor-kappaB expression, Nutr. Res. 28:487-493 This 8-week study using a rat tumor model showed that oral HMB attenuated the cachexic weight loss caused by the tumor, resulted in decreased tumor weight, and improved glucose and glycogen metabolism. Therefore, HMB at commonly used dosages maintained healthy tissues while helping inhibit the tumor tissue growth.
Eley, H.L., S.T. Russell, and M.J. Tisdale, 2008 Mechanism of attenuation of muscle protein degradation induced by tumor necrosis factor-α and angiotensin II by β-hydroxy-β-methylbutyrate., Am. J. Physiol. Endocrinol. Metab. 295:E1417-E1426
The author's first paper detailed HMB effect on maintaining protein synthesis even after administration of lipopolysaccharide, TNF-α and angiotensin II. This second set of experiments in cultured muscle cells showed that HMB attenuated a specific pathway involving caspase 3 and 8, PKR (RNA dependent protein kinase), and reactive oxygen species (ROS) known to activate the ubiquitin-protease pathway. These data provide evidence as to why HMB is effective in maintaining and building muscle mass in a wide range of conditions such as AIDS, cachexia and aging.
Eley, H.L., S.T.Russell, and M.J. Tisdale, 2008 Attenuation of depression of muscle protein synthesis induced by lipopolysaccharide, tumor necrosis factor, and angiotensin II by β-hydroxy-β-methylbutyrate, Am. J. Physiol. Endocrinol. Metab. 295:E1409-E1416
Lipopolysaccharide, tumor necrosis factor-α and angiotensin II are catabolic in nature and depress protein synthesis. In cultured muscle cells HMB attenuated the decrease in protein synthesis by stimulating factors involved in the mTOR/p70S6k pathway.
Eley, H.L., S.T. Russell, J.H. Baxter, P. Mukerji, and M.J. Tisdale, 2007 Signaling pathways initiated by ß-hydroxy-ß-methylbutyrate to attenuate the depression of protein synthesis in skeletal muscle in response to cachectic stimuli, Am. J. Physiol. Endocrinol. Metab. 293:E923-E931 Protein synthesis studies were conducted in a cachectic mouse model and in muscle cell cultures. The results demonstrate that HMB simulates protein synthesis in muscle by multiple mechanisms including the mTOR/p70S6k pathway. Many of these mechanisms are also shared with leucine. However, HMB is more potent than leucine in attenuating the development of cachexia and is better tolerated by oral administration.
Smith, H.J., P. Mukerji, and M.J. Tisdale., 2005 Attenuation of proteasome-induced proteolysis in skeletal muscle by ß-hydroxy-ß-methylbutyrate (HMB) in cancer-induced muscle loss, Cancer Res. 65:277-283 This study was conducted in a mouse model of cancer tumor growth. HMB was shown to maintain lean body mass and attenuate protein degradation through down regulation of the increased expression of key regulatory components of the ubiquitin-proteasome proteolytic pathway. HMB also stimulated protein synthesis.
Van Someren, K.A., A.J. Edwards, and G. Howatson, 2005 Supplementation with ß-hydroxy-ß-methylbutyrate (HMB) and α-Ketoisocaproic Acid (KIC) reduced signs and symptoms of exercise-induced muscle damage in man, Int. J. Sport Nutr. & Exer. Met. 15:413-424 This counterbalanced, crossover study in 6 non-resistance trained males given either a placebo or HMB/KIC (3 grams HMB and 0.3 grams KIC) showed that his combination reduced exercise-induced muscle damage.
Smith, H.J., S.M. Wyke, and M.J. Tisdale, 2004 Mechanism of the attenuation of proteolysis-inducing factor stimulated protein degradation in muscle by ß-hydroxy-ß-methylbutyrate, Cancer Res. 64:8731-8735 This In vitro study of chemical markers of proteolytic functions in muscle cell cultures showed that HMB inhibits activation of a major protease pathway in muscle, thus inhibiting protein degradation in muscle.
Vukovich, M.D., G. Slater, M.B. Macchi, M.J. Turner, K. Fallon, T. Boston, and J. Rathmacher, 2001 ß-Hydroxy-ß-methylbutyrate (HMB) kinetics and the influence of glucose ingestion in humans, J. Nutr. Biochem. 12:631-639 In 2 randomized trials the blood levels of HMB were examined after eight males took either HMB, HMB plus glucose, glucose alone, or placebo. These metabolic studies showed that the half-life of HMB in plasma is about 2.5 hours and that up to 85 percent of the HMB ingested is retained in the body. Simultaneous glucose ingestion did not affect the percentage of HMB retained.
Slater, G.J., P.A. Logan, T. Boston, C.J. Gore, A. Stenhouse, and A.G. Hahn, 2000 ß-Hydroxy-ß-methylbutyrate (HMB) supplementation does not influence the urinary testosterone:epitestosterone ratio in healthy males, J. Sci. Med. Sport 3:79-83 In this case study of six males taking HMB, the results demonstrated that HMB does not alter testosterone levels and infer that HMB acts through a mechanism other than testosterone.
Wilson, J.M., R.P. Lowery, J.M. Joy, J.A. Walters, S.M. Baier, J.C. Fuller, Jr, J.R. Stout, L.E. Norton, E.M. Sikorski, S.M.C. Wilson, N.M. Duncan, N.E. Zanchi, and J. Rathmacher, 2013 β-Hydroxy-β-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men, Br. J. Nutr. FV:1-7
This study in trained athletes demonstrated that HMB free acid taken before a muscle-damaging, resistance-training session decreases muscle damage and improves perceived readiness to train in the next session. Thus, the athletes were able to recover quicker and train harder sooner with HMB free acid supplementation.
Dunsmore, K. A., Lowery, R. P., Duncan, N. M., Davis, G. S., Rathmacher, J.A., Baier, S.M., Sikorski, E., Morrison, T. J., Naimo, M. A., Walters, J., Wilson, S. M. C., and Wilson, J. M., 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 This is the first 12-week study using the new delivery form of beta-hydroxy-beta-methylbutyrate, HMB free acid. Highly trained athletes underwent an intense, high-volume, resistance-training program, including a 2-week overreaching phase during weeks 9 and 10. HMB free acid supplemented subjects had greater strength gains, increased Wingate power, and increased muscle thickness compared with the placebo supplemented subjects. This study showed that even in highly trained athletes, HMB free acid results in greater training gains over a 12-week periodized resistance-training program.
Sikorski, E., Wilson, J. M., Lowery, R. P., Duncan, N. M., Davis, G. S., Rathmacher, J.A., Baier, S.M.,
Naimo, M. A., Wilson, S. M. C., Dunsmore, K. A., Walters, J., Joy, J., Morrison, T. J., 2012 The acute effects of a free acid beta-hydroxy-beta-methylbutyrate supplement on muscle damage following resistance training: a randomized, double-blind, placebo-controlled study, J. Int. Soc. Sports Nutr. 9:Suppl. 1:P27 This is the first resistance training study to examine the acute effects of HMB free acid supplementation on muscle damage and perceived recovery scale (PRS) when initiating a high-volume resistance-training program. The results showed that when compared to placebo, HMB free acid resulted in decreased CPK indicating decreased muscle damage, and an increase in PRS meaning the subjects felt more recovered 48 h after the training. In conclusion, HMB free acid minimized the initial muscle damage and improved recovery in trained athletes initiating a high-volume training program.
Davis, G. S., Lowery, R. P., Duncan, N. M., Sikorski, E., Rathmacher, J.A., Baier, S.M., Morrison,
T. J., Dunsmore, K. A., Naimo, M. A., Walters, J., Joy, J., Wilson, S. M. C., and Wilson, J. M., 2012 The effects of beta-hydroxy-beta-methylbutyrate free acid supplementation on muscle damage, hormonal status, and performance following a high volume 2-week overreaching cycle, J. Int. Soc. Sports Nutr. 9:Suppl. 1:P4 The overreaching cycle during a resistance-training program is designed to simulate muscle stress that is encountered during higher intensity training, peaking for competition, or multiple-game tournaments. In this study, trained athletes underwent a 2-week overreaching cycle after 8 weeks of intense resistance-training. HMB free acid supplementation resulted in decreased CPK, an indicator of muscle damage; decreased cortisol, a stress hormone; and maintained more strength throughout the overreaching cycle. In conclusion HMB free acid provided more muscle protection against the sudden increase in training intensity compared to the placebo.
Fuller J.C., R.L. Sharp, H.F. Angus, S.M. Baier, and J.A. Rathmacher, 2011 Free acid gel form of β-hydroxy-β-methylbutyrate (HMB) improves HMB clearance from plasma in human subjects compared with the calcium HMB salt, Br. J. Nutr. 105:367-372
The results of this research study demonstrate that a liquid gel form of HMB is more readily available to tissues when taken orally than the currently available powdered form, Calcium HMB. The results show quicker and higher plasma levels of HMB with improved utilization by the tissues. HMB free acid gel could improve HMB availability and efficacy to tissues in health and disease.
Rathmacher, J. A., S. Nissen, L. Panton, R. H. Clark, M. P. Eubanks, A. E. Barber, J. D'Olimpio, and N. N. Abumrad, 2004 Supplementation with a combination of beta-hydroxy-beta-methylbutyrate (HMB), arginine, and glutamine is safe and could improve hematological parameters, JPEN 28:65-75 Consumption of HMB, arginine, and glutamine by healthy, AIDS patients and cancer patients was studied. No adverse effects were seen and the mixture enhanced hematological parameters such as red blood cell numbers.
Williams, J. Z., N. Abumrad, and A. Barbul, 2002 Effect of a specialized amino acid mixture on human collagen deposition, Ann. Surgery 236:369-375 HMB combined with the amino acids arginine and glutamine increased collagen synthesis in human wound healing.
May, P.E., A. Barber, J.T. D’Olimpio, A. Hourihane, and N.N. Abumrad, 2002 Reversal of cancer-related wasting using oral supplementation with a combination of ß-hydroxy-ß-methylbutyrate, arginine, and glutamine, Am. J. Surgery 183:471-479 In this multi-center study, a combination of HMB, arginine, and glutamine was shown to improve body composition in cancer wasting by targeting nutrition to increase protein synthesis and decrease protein degradation.
Coelho, C.W. and T. Carvalho, 2001 Effects of HMB supplementation on LDL-cholesterol, strength, and body composition of patients with hypercholesterolemia, Med. & Sci. in Sports & Exer. 33:s340 In hypercholesterolemic men participating in an exercise program, HMB decreased LDL cholesterol by 28 percent as well as increasing strength and improving body composition. No changes in LDL were seen in the placebo group.
Zachwieja, J.J., S.R. Smith, S.L. Nissen, and J.A. Rathmacher, 2000 ß-Hydroxy-ß-methylbutyrate (HMB) is produced in vivo in humans from leucine, FASEB J. 14:A747 HMB is produced from leucine in humans and increasing plasma leucine will increase the rate of appearance and amount of plasma HMB.
Neighbors, K.L., J.W. Ransone, B.H. Jacobson, and R.G. LeFavi, 2000 Effects of dietary ß-hydroxy-ß-methylbutyrate on body composition in collegiate football players, Med. & Sci. in Sports & Exer. 32:s60 In this study HMB was shown to decrease body fat and improve body composition in these well-trained collegiate football players.
Ransone, J.W., K. L. Neighbors, T.B. Adams, B.H. Jacobson, and R.G. LeFavi, 2000 The effect of ß-hydroxy-ß-methylbutyrate supplementation on muscular strength in collegiate athletes during a strenuous exercise program, Med. & Sci. in Sports & Exer. 32:s61 This study is another showing HMB supplementation improved body composition in a brief, strenuous exercise program in highly trained athletes.
Clark, R.H., G. Feleke, M. Din, T. Yasmin, G. Singh, F. Khan, and J. Rathmacher, 2000 Nutritional treatment for acquired immunodeficiency virus-associated wasting using ß-hydroxy-ß-methylbutyrate (HMB), glutamine, and arginine: A randomized, double-blind, placebo-controlled study, JPEN 24:133-139 AIDS patients, who had previously lost body weight, gained back body weight and improved body composition as well as increased T-cells and decreased viral load when they consumed a dietary supplement containing HMB, arginine, and glutamine in this eight-week clinical study.
Byrd, P.L., P.M. Mehta, P. DeVita, D. Dyck, and R.C. Hickner, 1999 Changes in muscle soreness and strength following downhill running: Effects of creatine, HMB, and Betagen supplementation, Med. & Sci. in Sports & Exer. 31:S263 HMB and Betagen (HMB and creatine) were the only supplements shown to decrease muscle soreness after downhill running, and HMB, creatine, and Betagen all decreased the loss in strength associated with the running.
Rathmacher, J.A., S.L. Nissen, L. Panton, J. Fuller, Jr., R.H. Clark, G. Singh, and N.N. Abumrad, 1999 Safety of a nutritional mixture of ß-hydroxy-ß-methylbutyrate (HMB), glutamine, and arginine in healthy young adults and patients with AIDS, JPEN 23:S10 The nutrient mixture of HMB, glutamine, and arginine was well tolerated in both healthy males and patients suffering from AIDS with no adverse effects seen in either study.
Zachwieja, J.J., S.R. Smith, G.A. Bray, J.C. Lovejoy, T.L. Witt, J.P. DeLany, and J.A. Rathmacher, 1999 Effect of the leucine metabolite ß-hydroxy-ß-methylbutyrate on muscle protein synthesis during prolonged bedrest, FASEB J. 13:A1025 The trend for increased strength maintenance with HMB was not due to a change in muscle protein synthesis or whole-body protein turnover during periods of bed rest.
Macchi, M.B., M.J. Turner, J.A. Rathmacher and M.D. Vukovich, 1999 Influence of coingestion of glucose on ß-hydroxy-ß-methylbutyrate (HMB) metabolism in humans, FASEB J. 13:A909 The half-life of HMB in the blood was shown to be about three hours and was independent of glucose intake or insulin level.
Rathmacher, J.A., J.J. Zachwieja, S.R. Smith, J.L. Lovejoy, and G.A. Bray, 1999 The effect of the leucine metabolite ß-hydroxy-ß-methylbutyrate on lean body mass and muscle strength during prolonged bedrest, FASEB J. 13:A909 Three grams of HMB per day tended to decrease the strength loss associated with extended periods of bed rest.
Nissen, S. and N.N. Abumrad, 1997 Nutritional role of the leucine metabolite ß-hydroxy-ß-methylbutyrate (HMB), J. Nutr. Biochem. 8:300-311 This paper reviews the first seven human studies with HMB and summarizes health and safety data generated as well as the muscle and strength gain data from these studies. The only significant changes in blood chemistry are decreases in total and LDL cholesterol.
Nissen, S., L. Panton, J. Fuller, Jr., D. Rice, and R. Sharp, 1997 Effect of feeding ß-hydroxy-ß-methylbutyrate (HMB) on body composition and strength of women, FASEB J. 11:A150 In two separate studies, one with and one without exercise, women were supplemented with HMB. No effect of HMB on body composition was measured in the non-exercising group of women, but in women undergoing exercise, HMB improved body composition and had increased fat loss, and strength gains.
Cohen, D.D., 1997 The effect of ß-hydroxy-ß-methylbutyrate (HMB) and resistance training on changes in body composition during positive and negative energy balance – a randomized double-blind study, M.Sc. Thesis, St. Bartholomew's and Royal London School of Medicine and Dentistry – 0:Queen Mary and Westfield College, University of Lo This thesis showed that HMB helped maintain muscle mass while on a calorie-restricted diet.