All, Sports Nutrition

More Muscle Less Fat? The Skinny on HMB

The Skinny on HMB

Can this three letter supplement be all that it’s cracked up to be?

If you have been out of the loop, HMB, used by muscle builders for years, has started making waves for the general population. It’s making a bit of a splash because of its promises to reduce muscle breakdown, improve endurance and weight control. Basically, all the things that you would want in a training supplement, right?

So, the question then is, is it legit? Or are we just talking urban legend over here.

Let’s find out, shall we?

So….What is HMB?

The fancy chemical name is b-Hydroxy b-methylbutyrate. What a mouth full right?

In simple terms its a cousin of the branched chain amino acid leucine. Leucine has been known for a while in fitness circles for increasing strength, muscle and decreasing body fat (1).

Muscle Wastage

Proteolysis (aka the breakdown of muscle tissue) is a major cause of muscle soreness. This process was originally thought to be soothed by leucine. However, because leucine converts into HMB, scientists found out it was actually HMB doing all the heavy lifting! (Pun intended)

Also using leucine and HMB in combination can also provide great benefits for body composition over time.

Summary: HMB is the breakdown of an amino acid called leucine. It reduced muscle breakdown and muscle soreness.

What does HMB do, what are the benefits?

1. Lean Muscle Mass:

Basically, it works in two ways — it increases the effectiveness at which proteins combine together to form muscle while decreasing protein breakdown(1). This synergistic effect basically means you can pack on more lean mass more efficiently(2).

Increasing lean muscle mass has a huge affect on your metabolism. As muscle tissue is more metabolically active than fat cells, meaning they use more energy, your body’s natural ability to tear through excess energy is increased.

2. Strength:

A unique quality of this nutrient seems to be that it can increase strength even if a person is sedentary. In one study, the researchers compared strength performance results of sedentary, overweight women before and after six weeks of supplementing with HMB.

There was weight loss and fat loss over the course of the study in the group who took HMB, but the group also showed a significant improvement in their strength performance after 6 weeks (without following a weight training routine).(3)

This study proved that HMB can increase muscle strength without exercise, even in overweight, sedentary people(3).

New to Weight Training?

Newbies to weight training find the most benefit due to the high amounts of muscle damage and increased need for muscle recovery. While there’s evidence of increase in strength in groups who are brand new to resistance training, it may be less effective for the occasional exerciser or someone who doesn’t perform very challenging workouts(7).

3. Recovery:

Intense exercise can cause muscle soreness and pain due to the amount of damage and inflammation this type of exercise causes. As HMB increases the rate of muscle recovery, it allows you to heal from workout injury, reduces the amount of pain associated with muscle damage and muscle synthesis as well as reduce the time until your next visit to the gym (1).

4. Endurance:

Like to run? Or maybe row? In another study of a small group of elite male rowers they compared the impact of HMB on endurance cardiovascular training. Twelve weeks of supplementation increased the athletes’ VO2 max (aerobic endurance) and decreased their body fat(4). The study also indicated that the supplementation might have a positive impact on peak anaerobic power as well(4).

5. Weight Control:

One of the main draws of this new nutrient is its ability to create something called a net positive balance of muscle turnover, or in other words, creating more muscle and less muscle breakdown(1). So if you combine HMB with a caloric restricted diet, it can be effective at reducing fat whilst not getting the muscle wastage/ atrophy that sometimes comes with weight loss.

6. Aging:

Another study found that HMB levels change in the body as we age(5). It may be the main reason behind muscle wastage as age increases. This particular study also showed that differences in grip strength as well as general muscle mass was directly associated with differing levels of HMB.

Are there any potential risks of taking HMB?

Short term HMB supplementation appears to be safe. No studies on the safety of long term HMB supplementation have been undertaken although acute large doses appear to be free of side effects, as does an intake of 3 grams per day (9).

Which foods contain HMB?

Because HMB is a cousin of leucine, to increase your dietary intake you should focus on foods that are high in leucine. High levels of leucine are typically found in high-protein animal-and plant-based foods(8) Examples include:

HMB Foods; Cheese, fish and eggs.

The greater the amount of leucine in your diet, the more HMB will become available, but only about 5% of leucine is converted to HMB. For this reason, a HMB supplement is the most efficient way to get more in your diet.

When to take HMB

In short, for most people, 3 grams of HMB about an hour before exercise is ideal. However it is important that you consult a health professional before taking HMB. HMB can greatly vary in effectiveness depending on when you take it. For example when taken with carbohydrates or as part of a meal, HMB might take longer to become available for maximum benefit. For this reason, if carbs are taken at the same time, consume your HMB about 2 hours before your training session(1).

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Final Take

Overall, the beneficial effects of HMB seem to be tied with the intensity of the training and level of the athlete who is taking it. The groups who seem to have the greatest benefits from taking HMB are trained athletes who perform intense, challenging workouts that would otherwise be more damaging to the muscles(6). There have been no reported side effects and even more benefit when combined with other supplements like creatine. If you’re noticing a longer period of muscle soreness and struggling to get the results you want from your training, come talk to the Health Squared team about taking HMB and changing up your routine to be more challenging.


HMB has been shown to show the most benefit to those new to weight training, there’s less effect in highly trained individuals who aren’t performing exercises that challenge their bodies. HMB can also potentially reduce the amount of muscle loss due to aging.

Written by Naturopath Sam the Protein Man

To book a consult with Sam or one of other practitioners please click here for more information.


  1. Wilson, J. M., Fitschen, P. J., Campbell, B., Wilson, G. J., Zanchi, N., Taylor, L., … & Ziegenfuss, T. N. (2013). International society of sports nutrition position stand: beta-hydroxy-beta-methylbutyrate (HMB). Journal of the International Society of Sports Nutrition, 10(1), 6.
  2. Jówko, E., Ostaszewski, P., Jank, M., Sacharuk, J., Zieniewicz, A., Wilczak, J., & Nissen, S. (2001). Creatine and β-hydroxy-β-methylbutyrate (HMB) additively increase lean body mass and muscle strength during a weight-training program. Nutrition, 17(7-8), 558-566.
  3. Hashempour, A., Hooshmand, S., Tabesh, M. R., & Alizade, Z. (2019). Effect of 6-week HMB (beta-hydroxy-beta methylbutyrate) Supplementation on Muscle Strength and Body Composition in Sedentary Overweight Women. Obesity Medicine, 100115.
  4. Durkalec-Michalski, K., & Jeszka, J. (2015). The efficacy of a β-hydroxy-β-methylbutyrate supplementation on physical capacity, body composition and biochemical markers in elite rowers: a randomised, double-blind, placebo-controlled crossover study. Journal of the International Society of Sports Nutrition, 12(1), 31.
  5. Kuriyan, R., Lokesh, D. P., Selvam, S., Jayakumar, J., Philip, M. G., Shreeram, S., & Kurpad, A. V. (2016). The relationship of endogenous plasma concentrations of β-Hydroxy β-Methyl Butyrate (HMB) to age and total appendicular lean mass in humans. Experimental gerontology, 81, 13-18.
  6. Wilson, J. M., Lowery, R. P., Joy, J. M., Walters, J. A., Baier, S. M., Fuller, J. C., … & Duncan, N. M. (2013). β-Hydroxy-β-methylbutyrate free acid reduces markers of exercise-induced muscle damage and improves recovery in resistance-trained men. British Journal of Nutrition, 110(3), 538-544.
  7. Rowlands, D. S., & Thomson, J. S. (2009). Effects of β-hydroxy-β-methylbutyrate supplementation during resistance training on strength, body composition, and muscle damage in trained and untrained young men: A meta-analysis. The Journal of Strength & Conditioning Research, 23(3), 836-846.
  8. United States Department of Agriculture. Nutrient Lists – Leucine, from{“type”:”block”,”srcIndex”:0,”srcClientId”:”05050f3d-5cde-44fd-a012-3fbe162a771c”,”srcRootClientId”:”27252947-8e88-425a-ae43-cf3192df76cb”}

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