HMB: The Key To Increase Muscle Gains Or A New Fad?

HMB is the latest supplement that is making waves for its potential to increase muscle gains, improve body composition and improve muscle strength after resistance training. Traditionally used by bodybuilders, it has been catapulted into the general public’s sphere but is it worth all of the hype?

Where Does HMB Come From?

Hydroxymethylbutyrate or ꞵ-hydroxy ꞵ-methyl butyrate, also known as HMB for short, is a metabolite of the amino acid leucine. Leucine is an essential amino acid found in proteins in a group known as Branched Chained Amino Acids (BCAAs), which also includes isoleucine and valine.

More than one-third of your muscle protein is made up of Branched-Chain amino acids (BCAAs); leucine appears to play the most crucial role. Leucine is responsible for protein metabolism, regulation of blood sugar levels, muscle recovery and lean muscle growth.

HMB is a substance that your body naturally produces as a result of the breakdown of leucine.

When leucine is digested, it is broken down into the metabolite a-ketoisocaproate (KIC). Most KIC is metabolised into isovaleryl-CoA, and the rest, approximately 5%, is converted into HMB.

A 60-gram serving of leucine would provide 3 grams of HMB. 3 grams is the most common dose administered for studies in HMB.

Two forms of HMB are usually available, including:

• HMB Free Acid
• HMB Calcium Bound

There are no found differences between the two forms, with a 3-gram dose generating similar results.

How Does HMB Work?

Before jumping on the bandwagon, let’s dive into how HMB works.

The effects of HMB on muscle seem to be due to its activity on muscle protein synthesis and muscle protein breakdown (catabolism).

• HMB stimulates the mammalian target of rapamycin (mTOR) which controls the growth and production of protein in various cells, including muscle fibres.
• The Growth hormone/insulin-like growth factor axis activity may also be increased by HMB, which is an important factor in building muscle mass.
• The inhibition of two pathways, ubiquitin-proteasome system and caspases, by HMB reduces the breakdown of protein and reduces the loss of lean muscle mass.

HMB Dose

A 3-gram dose is the most common dose administered in studies. A 6-gram amount also had no adverse effects on cholesterol levels, blood glucose, liver function, kidney function and red or white blood cells. 

Is HMB Safe With Other Supplements?

HMB appears safe when combined with Creatine and other amino acids such as Arginine, Glutamine and Lysine. 

Does HMB Work?

If you’re sitting on the fence about whether or not to invest in taking HMB, look no further, as we will be diving deep into the science of HMB.

Research on HMB is quite varied. Several studies have supported the supplementation of HMB and improvement of exercise performance, but on the other hand, several studies conflict with these results.

HMB on Trained Athletes:

One study found that HMB supplementation may not be effective for trained athletes, including strength and power athletes and bodybuilders, to improve aerobic exercise performance.

A study on 28 football players taking 3 grams of HMB a day found no difference in the reduction of catabolism, strength, body composition and sprint performance.

HMB and Muscle Recovery:

The studies on HMB and muscle recovery are mixed, with most claiming that HMB has no significant effect on reduced exercise-induced muscle damage.

HMB and Muscle Gain:

A study on 40 athletes found no positive effects on muscle gain, catabolism, body composition or strength.

One study did find there were improvements in muscle mass and muscle strength in adolescent volleyball players, but there were no significant differences in anabolic indicators such as growth hormone, insulin growth-factor-1 or testosterone and no reduction of inflammatory mediators either.

HMB supplements also appear to be effective in helping elderly people increase muscle mass and strength to reduce sarcopenia (age-related loss of muscle mass).

Should You Take HMB?

Although some research favours the benefits of HMB supplementation, take it with grain as salt. There are a lot of mixed results, and overall there seems to be no benefit for trained athletes. More research is needed to demonstrate that this supplement is worth the investment. HMB supplement in Australia is not banned or is a prohibited substance. However, if you want to build on more muscle, you probably should invest in leucine. Leucine still takes the crown as the number one for muscle gains - first because it's a cheaper alternative and appears more potent than HMB.