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What is it?

HMB is a substance formed naturally when the body breaks down the amino acid leucine, a component of protein.

Does it occur naturally in the body?


What are the claims?

There are two. The first is that if you ingest amino acids, you'll be able to increase protein and increase muscle mass. The second is that HMB will decrease the amount of muscle breakdown caused by strength training.

Does it work?

A review of studies published in the journal Sports Medicine indicates it may have a small effect, but only on untrained athletes just beginning a weight training program. There have also been some studies indicating it may be helpful for increasing lean tissue on AIDS and cancer patients.

The theory that HMB can build muscle by decreasing the amount of muscle breakdown is problematic because building new muscle requires some breakdown of protein within the muscle tissue.

An interesting note: Two studies did show that subjects who took HMB saw a reduction in both blood pressure and cholesterol. While researchers were quick to note people should not start taking HMB to reduce either blood pressure or cholesterol, it is something that more studies are currently looking into.

What are the dangers?

The current studies do not show any significant adverse health effects from taking HMB.

The Bottom Line

HMB does not appear to influence body composition without the stimulus provided by resistance training. HMB does seem to offer some benefit for people with AIDS and cancer, provided it is prescribed and monitored by a doctor.

Unless prescribed by a doctor for a medical condition, we cannot recommend the supplement HMB for people simply looking to build muscle.

Links for More Info

Centers for Disease Control and Prevention (CDC) Logo and Link
Centers for Disease Control and Prevention

United States Food and Drug Administration (FDA)

Herbs, Botanicals & Other Products - Extensive Information from the Memorial Sloan-Kettering Cancer Center

National Center for Complementary and Integrative Health - Overviews on Herbal Treatments and Supplements

National Institutes of Health

National Institutes of Health - Office of Dietary Supplements
National Institutes of Health - Office of Dietary Supplements

Operation Supplement Safety
Operation Supplement Safety

United States Department of Agriculture (USDA) Logo and Link
United States Department of Agriculture

WebMD Logo and Link
WebMD - Helping you make better decisions for life.

We at WeBeFit DO NOT recommend ANY supplements to ANY of our clients. ONLY a licensed Nutritionist or Medical Doctor can make those recommendations based on your individual needs.

This is being provided for INFORMATIONAL and EDUCATIONAL purposes only.

CAUTION: These supplements have not been evaluated by the Food and Drug Administration (FDA) for safety, effectiveness or purity. There may be unknown risks associated with taking any supplements. There are no regulated manufacturing standards for companies that make supplements. There have been instances where herbal or health supplements have been sold that were contaminated with toxic substances. If you should choose to purchase herbal or health supplements, please only purchase them from a reliable source to minimize the risk of contamination.

If you should decide to use ANY supplement, ALWAYS consult your doctor or Nutritionist first.

Updated 9/2/2006