Everything You Need to Know About HMB


Holding onto our strength and muscle is vital to living a long, healthy life. In fact, there’s a direct correlation between strength and longevity. Of course, that begins with a foundation of a healthy diet (with plenty of protein) combined with regular exercise (especially some type of resistance training). Other nutrients, such as creatine and HMB, may also help maintain muscles. While it may not be as well-known as protein or creatine, the HMB benefits for muscles are well-documented.

What Is HMB?

HMB is the acronym for “beta-hydroxy beta-methylbutyrate.” It’s also known as beta-hydroxy beta-methylbutyric acid and hydroxymethylbutyrate. This metabolite of the amino acid leucine has gained popularity as a supplement for helping aid muscle growth and exercise performance.

Small amounts of HMB are produced by the body naturally when the body breaks down the branched-chain amino acid (BCAA) leucine, which it uses for muscle repair and growth. 1 However, less than five percent of the leucine consumed is converted into HMB. 2
HMB can also be found in small amounts in some foods, such as catfish, avocado, grapefruit, cauliflower, and alfalfa. The body then uses this HMB for protein metabolism, muscle growth, and insulin activity. 3 Having sufficient levels of HMB in the body has been correlated with muscle mass. 4

To get enough HMB for the HMB benefits for muscles, though, it’s more commonly used as a dietary supplement. 5 HMB supplements hit the market in the early 1990s and quickly became popular with bodybuilders and other physique athletes. It can now be found in a variety of forms, including powders, capsules, and tablets.

Some of the potential HMB benefits for muscles shown in research include:

  • Increased exercise recovery and performance
  • Reduced muscle damage
  • Increased aerobic and anaerobic capacity during high-intensity workouts
  • Boosts in power output when combined with resistance training
  • Decreased muscle tissue breakdown by increasing protein synthesis
  • Diminished muscle damage
  • Decreased fat mass and improvements in body composition
  • Increased muscle growth, especially in untrained and mature adults 3, 6 – 20

HMB’s ability to boost muscle growth has been debated, yet even more research shows it may help fend off the loss of muscle mass as we get older or more sedentary. 10, 21 – 23

How Does HMB Impact Muscles?

Muscle within the body is constantly being broken down and rebuilt. Amino acids that are found in proteins within our diet are used to fuel this process, known as protein turnover. The balance of breakdown and rebuilding is what allows us to maintain or build muscles—as long as protein synthesis is equal or greater. On the other hand, if protein breakdown is greater, it leads to muscle loss.

Eating enough protein is a big piece of this puzzle, but even when you’re eating enough protein, if the muscle metabolism is sluggish, it can inhibit gains. HMB is unique in that it appears to help on both sides of the muscle process. On one side, it appears to help activate muscle protein synthesis. On the other, it appears to help lessen protein breakdown. Together, this helps balance muscle protein turnover, so you keep your hard-earned muscle and even build more.

The typical recommended amount of HMB for muscle is three grams per day, split into two servings. Studies have found HMB muscle benefits after only a couple of weeks, though more measurable results take up to four weeks or more, depending on your overall training, nutrition, and other supplementation.

HMB Side Effects

HMB hasn’t been studied with pregnant or nursing moms, but for teenagers to adults to seniors, it appears to be safe, with little to no reported side effects. Still, before using supplements, it’s always a good idea to discuss it with your healthcare team.

What Other Supplements Work Well with HMB?

To get the optimal HMB muscle benefits, some experts suggest ensuring you are getting enough vitamin D. One study, for instance, found that using vitamin D3 with HMB helped improve muscle function in older adults, even when they were sedentary. Vitamin D3 has also been associated with enhanced strength and muscle function. 24

Other supplements to include with HMB for muscle building include creatine, which has been shown to promote muscle size and performance, and betaine, which helps encourage muscle hydration. It’s also often taken with protein powders (like whey) and carbohydrates. 25

HMB Benefits for Muscles: A Wrap-Up

There’s no doubt that regular exercise combined with a nutrient-dense diet that’s rich in protein can help build muscle. It doesn’t hurt to look for an extra edge or at least a little support, especially as you age, when recovering from injury, or to recover from intense training.

Potential HMB benefits for muscles included increased strength, reduced muscle damage, and even positive changes in body composition when compared to a placebo. And it may be even more effective when combined with vitamin D and creatine.