HMB

Geschatte leestijd: 5 minuten HMB (beta-hydroxy-beta-methylbutyric acid) is a supplement that has been extensively researched. It is a substance that your body can produce itself, in small amounts, from one of the essential amino acids in your diet. By supplementing larger amounts of it, you could potentially become stronger and more muscular. At least, that’s the idea. But what does scientific research actually say about this? Some studies suggest that HMB works even better than anabolic steroids in trained athletes, while other studies have failed to demonstrate any effect at all. This controversy has surrounded the supplement to a considerable extent. In this article, I will first give you a brief introduction to HMB. Then I will outline and discuss the remarkable results from the literature.

What is HMB?

HMB is a substance that your body can produce from leucine, one of the nine essential amino acids in your diet. Leucine plays an important role in muscle growth. It is closely involved in the regulation of muscle growth. Part of this important role is attributed to the conversion of leucine into HMB. It is estimated that ~5% of ingested leucine is converted into HMB [1]. This means that most people, even on a high-protein diet, produce less than 1 gram of HMB from leucine per day. A supplement of 3 grams per day is recommended. HMB increases protein synthesis (probably less than leucine itself) and inhibits protein breakdown [2]. It has also been suggested that it improves membrane integrity [3]. This could mean that it limits muscle damage, but this has not been directly studied. However, there are many indirect indications that it limits muscle damage, as inferred from surrogate markers (such as serum creatine kinase) for this. It is generally assumed that HMB supplementation is especially useful in intensive training schedules that cause a lot of muscle damage (and muscle protein breakdown). As early as 1996, an experiment looked at the effect of HMB supplementation on body composition and muscle breakdown [3]. That’s only four years after the first experiment in humans with creatine supplementation by sports scientists [4]. In that sense, HMB as a supplement is about ‘as old’ as creatine. For this reason, there is quite a bit of scientific research available. The experiment from 1996 was conducted under the direction of Professor Steven Nissen. Steven Nissen had already started his own supplement company called Metabolic Technologies, Inc. (MTI) in 1990. He held the patent for the supplement and consequently had a significant stake in the success of the product. I believe that this stake played a significant role in the varied results that the supplement shows in the literature.

HMB better than anabolics?

The title of this article has a very high clickbait content. But, joking aside, there are indeed studies that suggest that HMB works better than anabolic steroids. In 2014, a study was published from the lab of Jacob Wilson in which trained athletes were supplemented with HMB for 12 weeks in combination with a strength training program. And when I say trained, I mean really trained. Not beginners who had just dabbled in the gym for a few months. On average, the subjects were squatting, bench pressing, and deadlifting 1.7, 1.3, and 2.0 times their body weight, respectively. After 12 weeks, the 1-RM squats in the HMB group increased from 143.7 kg to 179.9 kg (+25%), 1-RM bench presses from 112.4 kg to 125.2 kg (+12%), and 1-RM deadlifts from 170.3 kg to 198.4 kg (+16%). In the placebo group, the strength gains were much smaller, with increases of only +5%, +3%, and +9%, respectively. But that’s not all. In the HMB group, lean body mass increased by 7.4 kg, while fat mass decreased by 5.4 kg! Holy shit. These results quickly led to a comparison with a study in which strength training was combined with a high dose of testosterone injections (600 mg per week) [5]. Subjects who combined strength training with testosterone were only able to gain 6.1 kg of fat-free mass in 10 weeks and did not lose any fat. In short: HMB better than steroids. In 2016, another study was published by Jacob Wilson’s lab [6]. Here, HMB supplementation was combined with ATP for 12 weeks. This resulted in an increase of 8.5 kg in lean body mass for the subjects.

Criticism from the scientific community

You can imagine that Wilson’s results led to harsh criticism on social media. No one believes results like that. According to these results, HMB should work so incredibly well that it is comparable to anabolic steroids. In addition to criticism on social media, it has also led to fierce criticism from prominent sports scientists in the literature [7-9]. Not only were the results absurd, but there were also shortcomings in the studies. Wilson is not exactly the most reliable figure in science, and the studies were also funded by MTI. Moreover, several of the co-authors were employees of this company. Given that such absurd results have not been found by other groups, it can be concluded overall that these results are nonsense.

What the rest of the literature says about HMB

Fortunately, we have more research material available than just Wilson’s results. However, a considerable number of studies involve funding from MTI or employees (especially Steven Nissen himself) as co-authors of the publications. Especially these studies show positive results on strength or body composition. However, most independent studies do not show any effect. This suggests that if HMB does work, the effect is likely to be small. These studies also have a limited number of subjects, making it difficult to detect a small effect. I would like to add that a study showed that HMB inhibited protein breakdown in an insulin-independent manner [2]. Normally, a meal already provides an almost maximal inhibition of protein breakdown due to the insulin response triggered by a meal (the threshold for maximum inhibition is quite low, so a protein shake achieves this). However, people who practice intermittent fasting have a very low insulin level for a large part of the day. HMB supplementation may be useful in such a situation to inhibit protein breakdown, although this has not been directly tested.

Conclusion

HMB is a substance that we produce ourselves in small amounts from leucine. By supplementing it (3 grams per day), you get a lot more than you would produce yourself. Two studies suggest that HMB supplementation works better for gaining muscle mass than high doses of testosterone, but these results should be taken with a grain of salt. They are unbelievable and have received a lot of criticism on social media, as well as in the scientific literature. HMB supplementation may work a little. It is supposed to work especially in situations with intensive training or, for example, during intermittent fasting, during the fasting periods to inhibit protein breakdown.

References

1. Zanchi, Nelo Eidy, et al. “HMB supplementation: clinical and athletic performance-related effects and mechanisms of action.” Amino acids 40.4 (2011): 1015-1025.
2. Wilkinson, Daniel J., et al. “Effects of leucine and its metabolite β‐hydroxy‐β‐methylbutyrate on human skeletal muscle protein metabolism.” The Journal of physiology 591.11 (2013): 2911-2923.
3. Nissen, S., et al. “Effect of leucine metabolite β-hydroxy-β-methylbutyrate on muscle metabolism during resistance-exercise training.” Journal of Applied Physiology 81.5 (1996): 2095-2104.
4. Wilson, Jacob M., et al. “The effects of 12 weeks of beta-hydroxy-beta-methylbutyrate free acid supplementation on muscle mass, strength, and power in resistance-trained individuals: a randomized, double-blind, placebo-controlled study.” European journal of applied physiology 114.6 (2014): 1217-1227.
5. Bhasin, Shalender, et al. “The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men.” New England Journal of Medicine 335.1 (1996): 1-7.
6. Lowery, Ryan P., et al. “Interaction of beta-hydroxy-beta-methylbutyrate free acid and adenosine triphosphate on muscle mass, strength, and power in resistance trained individuals.” The Journal of Strength & Conditioning Research 30.7 (2016): 1843-1854.
7. Hyde, Parker N., Kristina L. Kendall, and Richard A. LaFountain. “Interaction of Beta-Hydroxy-Beta-Methylbutyrate Free Acid and Adenosine Triphosphate on Muscle Mass, Strength, and Power in Resistance-Trained Individuals.” The Journal of Strength & Conditioning Research 30.10 (2016): e10-e11.
8. Gentles, Jeremy A., and Stuart M. Phillips. “Discrepancies in publications related to HMB-FA and ATP supplementation.” Nutrition & metabolism 14.1 (2017): 42.
9. Phillips, Stuart M., et al. “Changes in Body Composition and Performance With Supplemental HMB‐FA+ ATP.” The Journal of Strength & Conditioning Research 31.5 (2017): e71-e72.