Summary

A metabolite of the amino acid leucine, HMB was introduced in 1996 as a performance micronutrient and is now used by countless athletes — from bodybuilders to marathon runners to extreme adventure sports athletes — anyone involved in the rigorous clutches of strenuous physical activity. But make no mistake, this is not some supplement fad: this one's been shown in clinical research to help individuals build new muscle tissue, burn greater amounts of fat, recover faster, and feel less sore after intense workouts.

Other names for HMB

beta-hydroxy-beta-methylbutyrate

Where to find HMB

Our bodies produce small amounts of HMB naturally. This nutrient is also found in breast milk, which you wouldn't be drinking unless you were an infant, and in catfish and citrus fruits, albeit in very small amounts.

Why athletes use HMB

Any athlete seeking to enhance recovery, increase muscle growth, decrease muscle soreness, and boost fat loss should certainly consider this unique performance micronutrient. It's not a "magic bullet," though. For the greatest potential benefits, it must be combined with an intense exercise program or vigorous physical activity and, some experts suggest, a higher protein nutrition plan. But, when used as "suggested," many athletes have discovered a world of difference in their bodies and their performance after adding HMB to their supplement programs.

Ways that HMB can enhance Muscle Gain & Recovery:

• Prevent muscle breakdown by stabilizing muscle cells
• Improve the growth of new muscle tissue by increasing protein synthesis
• Reduce the likelihood of muscle fatigue and soreness in endurance athletes

Ways that HMB can enhance Fat Loss:

• Support fat burning in muscle cells to help the reduce bodyfat

Signs of HMB deficiency

No deficiency conditions exist; however, intense physical activity and/or improper diet could deplete levels of HMB within the body.

Potential uses for HMB

Research indicates that HMB may be useful in the treatment of:

• Catabolism (muscle wasting)

More about HMB

A fairly new performance micronutrient, HMB (an acronym for "beta-hydroxy-beta-methylbuterate") was introduced in 1996 and is now used by countless athletes — from bodybuilders to marathon runners to extreme adventure sports athletes — anyone involved in the rigorous clutches of a strenuous exercise program.

This amino acid metabolite has been shown to be an important nutrient for reducing the amount of muscle damage following intense physical activity of any type, including exercise. And, it is often highly recommended when an athlete changes his or her training program or when coming back after a brief layoff or injury. This is because during these times of change or after an absence, it's more difficult to recover from the damage our workouts inflict, and supplementing with HMB may not only improve recovery but has been shown to be beneficial for preventing further muscle breakdown.

What it is and how it works

HMB is a naturally occurring metabolite of the essential amino acid leucine. Basically, small amounts of HMB are found naturally in various foods we eat that contain leucine. Once ingested, the amino acid leucine breaks down to produce HMB, albeit in extremely small amounts. However, to induce any sort of performance-enhancing effects, our bodies require much greater amounts than we can get from the leucine in foods. And besides, who would want to eat catfish or grapefruit (the two highest sources) every day?

Supplementing provides the body with sufficient amounts of HMB to help prevent the breakdown of muscle tissue after intense exercise, while increasing the metabolism of fats.

As one of the most well-researched supplements on the market, HMB has been shown to help boost muscle-protein retention as well as assist the body in holding onto important amino acids needed for protein synthesis. In the real world, this simply equals results. HMB has been documented to help athletes gain muscle, lose fat, improve recovery, and decrease muscle soreness.

Research reveals

In one study, athletes who supplemented with three grams of HMB a day for three weeks gained three times more muscle mass and two and a half times more strength than folks who worked out the same but used a placebo instead of the real thing. Many other studies show similar results.

Even more recently, HMB has been shown to be beneficial for endurance athletes. In one study, runners who supplemented with 3 grams of HMB were found to experience 50% less muscle damage than those who used a placebo. Plus, the supplemented group was found to either maintain or improve leg strength, whereas the placebo group progressively lost leg strength.

Other studies have revealed it may help increase VO2max — which loosely translated means increased aerobic capacity and performance — as well as decrease lactic acid buildup and thereby reduce muscle fatigue and post-workout soreness.

While most research on HMB shows positive effects, one recent study did show that with short-term supplementation of 40 mg per kg of bodyweight, HMB had no beneficial effects when it came to improved muscle recovery or reduced muscle damage. So a longer supplementation period may be needed to see results.

In conclusion

Any athlete seeking to enhance recovery, increase muscle growth, decrease muscle soreness, and boost fat loss should certainly consider this unique performance micronutrient. Studies have shown HMB is not gender specific, and it doesn't care about age. It works just as well for women as it does for men, and it works as well for those who are 81 as it does for those who are 18. But it's not a "magic bullet." For the greatest potential benefits, it must be combined with an intense exercise program or vigorous physical activity and, some experts suggest, a higher protein nutrition plan.

Nonetheless, when used as "suggested," many athletes have discovered a world of difference in their bodies and their performance after adding HMB to their supplement programs.

Amount

Three grams per day is the most effective amount recommended for athletes or those seeking to improve their physiques (i.e., bodybuilders).

Optimal amounts

Experts are finding that the most effective amount of HMB depends more on an individual's weight, suggesting a 170-lb male might need 3 grams, a 120-lb female may need only 2 grams, and men who weigh over 200 lbs might need 4 grams a day. Research has revealed the optimal range to be 1 gram per 25 kg of bodyweight (e.g., a 200-lb male would weigh about 90 kg — there are 2.2 lbs in a kilogram (200 / 2.2 = 90); thus, he should supplement with approximately 4 grams of HMB (90 / 25 = 3.6) per day).

Timing

HMB supplementation is often recommended with meals, and supplementation should be divided into equal dosages throughout the day: one gram three times per day.

Synergists of HMB

Anecdotal reports have revealed time and again the synergistic properties of combining HMB with creatine (monohydrate) for greater effects.

Consuming HMB with one gram of Vitamin C immediately after an intense workout may significantly minimize muscle soreness.

Research also indicates that HMB combined with glutamine may help prevent muscle wasting and weight loss in people with AIDS and cancer. This may also support the practice of a post-workout combination to avoid muscle breakdown (catabolism).

Safety of HMB

Pregnant or lactating women should discuss any nutritional/dietary supplement with their physicians before beginning supplementation.

Toxicity of HMB

No known toxicity.

Bans and restrictions

None reported.

• Nissen, S., et al., "Beta-Hydroxy-Beta-Methylbutyrate (HMB) Supplementation in Humans Is Safe and May Decrease Cardiovascular Risk Factors," J Nutr 130.8 (2000) : 1937-45.
  
• Nissen, S., et al., "Effect of Beta-Hydroxy-Beta-Methylbutyrate (HMB) Supplementation on Strength and Body Composition of Trained and Untrained Males Undergoing Intense Resistance Training," FASEB J 10 (1996) : A287.
  
• Nissen, S., et al., "Effect of Leucine Metabolite Beta-Hydroxy Beta-Methylbutyrate on Muscle Metabolism During Resistance-Exercise Training," J Appl Physiol 81.5 (1996) : 2095-104.
  
• Nissen, S., et al., "Effect of Supplemental Beta-Hydroxy-Beta-Methylbutyrate (HMB), Glutamine, and Arginine on Skeletal Muscle Mass in AIDS Patients," JPEN 23.1 (1999) : S7.
  
• Nissen, S., and Abumrad, N.N., "Nutritional Role of the Leucine Metabolite Beta-Hydroxy-Beta-Methylbutyrate (HMB)," J Nutr Biochem 8 (1997) : 300-11.
  
• Paddon-Jones, D., et al., "Short-Term Beta-Hydroxy-Beta-Methylbutyrate Supplementation Does Not Reduce Symptoms of Eccentric Muscle Damage," J Sport Nutr Exerc Metab 11.4 (2001) : 442-50.
  
• Vukovich, M.D., and Adams, G.D., "Effect of Beta-Hydroxy-Beta-Methylbutyrate (HMB) on VO2 Peak and Maximal Lactate in Endurance Trained Cyclists," Med Sci Sport Exerc 29.5 (1997) : S252.