HMB: Does it Build Muscle?
by Paul Cribb, B.H.Sci HMS
AST Director of Research
Hamlet said to his faithful friend Horatio in Shakespeare's classic tale, "Something is rotten in Denmark". By this, Hamlet meant something very strange was going down, that things were not quite right in his home country. Well, there is something rather rotten about the sports supplement HMB and I'll tell you what it is.
HMB (beta-hydroxy beta-methylbutyrate) was launched on to the sports supplement market back in 1996 by a rather savvy entrepreneur. It was a well-marketed product, surrounded by a lot of hype and very little science. It is still one of the most advertised products in the sports supplement industry. Yet there is still only one research paper (published at the time of its launch) that demonstrates any muscle building effect from HMB use ¾ and that study used untrained individuals [1].
There have been a number of reports presented in abstract form at various sports science conferences around the world and some have showed beneficial effects [2-6]. Yet none of these studies have been published in full in a peer-reviewed journal. Why? I don't know. This is particularly odd as evidence of any nutritional supplement that can enhance body composition and athletic performance is such a hot topic. In May 2000, one published study involving experienced bodybuilders clearly demonstrated that HMB exerted no muscle building effect, even at double the prescribed dose [7].
Recently, another research study involving experienced bodybuilders using HMB was published. This study examined HMB's muscle building effects during eight weeks of resistance training [8]. The results obtained were rather strange. The methodology used was very unusual and the way in which the data was interpreted by the researchers was very strange to say the least!
The research???.
The study involved 37 male weight trainers divided into three groups. Group one was given 3-grams of HMB. Group two was given 6-grams and group three 0-grams (a sugar placebo) of HMB per day. Three grams of HMB per day is the prescribed dosage that will, supposedly, reduce muscle damage significantly and increase strength and lean mass. Body composition (lean and fat mass) was assessed, as well as strength (by 1-rep max), peak isokinetic torque in leg muscles and plasma creatine phosphokinase (PK) activity; this provides an indication of muscle damage.
The results???.
After eight weeks of weight training, the data showed no differences between HMB or the placebo in peak muscle torque, muscle strength and body fat. Apart from the first weight training session, the data on PK levels showed no differences between the groups either. Remember, a reduction in muscle damage is one of the big claims made by the marketers of HMB. However, HMB failed to produce any significant reduction in PK levels, indicating that HMB supplementation does not reduce the muscle damage created by resistance training. This result was confirmed by a previous study [7].
A reduction in muscle damage is one of the big claims made by the marketers of HMB. However, the research on experienced bodybuilders show that HMB does not reduce muscle damage.
The data on changes in lean mass (muscle) obtained in the present study was not impressive either. In fact, the phase highly speculative comes to mind when assessing the results.
In this study, the group taking 3-grams of HMB per day gained just under 4-pounds (1.9-kgs) of lean mass after 7-weeks of training. The group taking the placebo gained 2.2 pounds (1-kg), however, the group taking 6-grams of HMB per day did not produce any gain in muscle mass!
Now, I aint the smartest guy walking around, but common logic dictates that if 3-grams of HMB per day increases muscle mass by around 4-pounds, then taking 6-grams (double the recommended dose) should produce at least the same gains, if not, more. However, in this study the group taking 6-grams of HMB a day produced zero gains! A result worse than the group taking a sugar-based placebo!
The real eye-opener was the fact that the researchers (authors) of this study when on to suggest that HMB supplementation is effective at increasing muscle mass. I cannot see how results could possibly be interpreted in this way. "A very mixed result" would be a more realistic interpretation. However, read on because now the plot really thickens.
This is the second study to demonstrate that taking 6-grams of HMB a day (double the prescribed dose) produces zero gains in muscle!
When body composition assessment is the primary focus of a research study, the most accurate methods are almost always used. Underwater weighing and DEXA (duel energy x-ray absorptiometer) are the most reliable and credible methods of assessing changes in body fat and muscle mass. The researchers of this study chose to use only the skin fold caliper technique. Now, using skin fold calipers (pinching and measuring the skin fold) to guestimate body fat and muscle mass is okay for the local gym or fitness center. However, it is commonly known that even if the technician is highly skilled, there is still an enormous amount of room for error with this technique.
In this day and age, when highly accurate body composition technology is readily avalible, the skin fold technique is a stone-age choice. As the sole method for body composition assessment in university research, it is a pitiful choice. Especially when you consider that this study was produced by one of the largest, best equipped university sports science facilities in the world.
The clear science on HMB
Let me be very clear on the research behind HMB for bodybuilding. To date there is only one paper that has been published that demonstrates any muscle building effect. This is the same paper used to initially launch HMB more than five years ago, and this research involved untrained subjects. Two studies that used trained lifters showed HMB produced zero benefits, at double the recommended dose. The most recent research has produced results that are best, unconvincing, and after carefull assessment can only be described as highly questionable.
Don't get me wrong; I have no problem with any company that can manufacture a quality supplement that works. The entire industry gains credibility when this happens.
However, the fact is that HMB continues to be marketed to athletes as a supplement that enhances recovery, strength and muscle growth. This is a complete sham. I do have a problem with marketers hyping a supplement as a research-proven muscle builder while the real scientific evidence shows the complete opposite. The next time you see an advertisement promoting HMB as a research-proven supplement that builds muscle, be very skeptical. Not only of the product, but also supplement company that markets it.
http://www.ast-ss.com/articles/article.asp?AID=83
