HMB at the bottom
You could say that the HMB supplements is one of the most excitement (and controversy) has created in recent years. This fault, they have certain studies showing a radical change at body composition, resulting in a gain 7 kg “muscle tissue” also lose fat 5 kg 1. Other studies 2,3 show how HMB helps maintain muscle mass, which would help prevent muscle loss in the population that can not train (case of injury).
HMB Ca-HMB-VS FA
The problem we found is that HMB is found in two forms:
At one end of the HMB-Ca (as calcium salt) and HMB-FA in free acid form, which patent has the Musclebuilding (Clear Muscle).
In the first case, the bio availability of HMB is much lower, so that plasma levels of this will be lowered compared with HMB-FA, as we see in the graph below:
For those @ s who do not know, HMB is a metabolite of leucine, in other words, leucine is the precursor of HMB. However, only 5% of leucine becomes HMB 4, so need to ingest about 60g of leucine to produce 3g HMB, hence the interest in the form of supplementation bio available.
Although at first you may think that leucine can have the same mechanism hormonal level, reality is quite different. It is true that leucine helps maintain muscle mass since it promotes protein synthesis at a muscular level (with other locations such as our reserves of fat or liver). However, leucine does not favor higher levels of IGF-1 (insulin growth factor) 5, which if it happens when we consume HMB-FA 6.
The IGF-1 activates the cascade related muscle growth and development level, besides inhibiting the pathways associated with protein degradation (through FOXO), which would explain the beneficial impact of HMB on muscle.
Hormonal effects of HMB-FA
As observed in this figure 7, IGF-1 promotes muscle growth and prevents loss caused by use of drugs or injury.
Early studies with HMB were carried out in 1996 8 where they took a group of people and given amounts of HMB 3: 0, 1.5 and 3 grams of HMB, for the effect level had body composition.
What was observed is that there was a negative relationship between HMB and protein breakdown, ie, with increasing the dose of HMB, decreased the amount of muscle protein is degraded. This led to a greater interest in the HMB and body composition, obtaining modest results versus placebo 9 in which 1.4% gained muscle and lost 1.1% fat.
HMB and muscle composition
When we reviewed the literature on the HMB, we can find the following:
As we see, the HMB can help people who are easy to lose muscle mass, but in healthy subjects is difficult hypertrophy. As I mentioned before, these studies are based on the Ca-HMB, but not in the HMB that is as free acid (HMB-FA).
Recently, it has been studied as HMB-FA affects the metabolic level. To this, it was tested in healthy subjects with a relatively low percentage of fat (13%) and with at least 7 years of training. As expected, plasma levels of HMB were pretty good, compared to other studies where HMB-FA is used.
At the level of testosterone and growth hormone, the following was obtained:
It was observed that in both groups, testosterone rose just at the end of training, however, 30 minutes levels were reduced to identical to pre-training levels, which would explain why raise-training post testosterone has no effect on muscle mass. On the other hand, if higher levels of growth hormone (GH) in the group consuming HMB-FA was observed.
My opinion, these higher levels of the hormone, could get much cheaper shaped anaerobic workouts, since we produce a lot of lactate (hence the importance of proper carbohydrate intake and not a ketogenic diet). These elevated lactate levels, help increase the release of growth hormone 10.
In theory, one might think that these higher levels of growth hormone lead to greater muscle mass, but this does not happen in practice. Much of the benefits on protein synthesis and thus on muscle mass is due to IGF-1, which lines discussed above which rises with the consumption of HMB-FA. Perhaps we have to wait for more studies out how free acid (HMB-FA) to see if this new supplement can actually lead to these results it promises.