Myostatin inhibition is the new “hot” thing on the bodybuilding block. This is because researchers found that myostatin is a negative regulator of muscle mass. In other words, inhibit myostatin in skeletal muscle, and watch your muscles grow. Unfortunately most of the myostatin research is limited to hard to find, and often expensive drugs. In addition the quality provided by many “research chemical labs” is questionable at best. So where does that leave us? We need something natural, something that inhibits myostatin, or at least has the potential to decrease myostatin. Does that even exist?
A major player in skeletal muscle fibrosis is transforming growth factor-b1 or TGF-β1. In fact TGF-β1 is elevated in injured muscle and those suffering from muscular dystrophy. An often cited study was looking at skeletal muscle injury and therapy methods (1). Using a non-steroidal anti-inflammatory (NSAID) decreases regeneration, and increases fibrosis. Fibrosis in skeletal muscle is essentially connective tissue that repairs the area, but also directly competes with muscle regeneration. In other words if you suffer from an acute muscle injury, your body will repair the area, but it may not be as strong as it once was simply because fibrous tissue is interfering with high quality muscle tissue regeneration.
The same study we referenced earlier on the repair of skeletal muscle injury also wanted to gain a better understanding of the relation of myostatin to TGF-β1. Specifically to see if myostatin played a role in skeletal muscle fibrosis as previous research had indicated may be true. The researchers studied many things, but one part of the study specifically compared normal mice and myostatin knockout mice. They purposely injured the mice by lacerating the muscle, and then stained the fibrous connective tissue of each animal group. Below is a photo of the difference in tissue quality. What you will notice is far less fibrotic tissue (blue stain) in the myostatin deficient mice (right) than in normal mice (left):
They found that there was about 4% less fibrous tissue at both 2 weeks from injury as well as 4 weeks out from injury. Previous research had already shown that TGF-β1 plays a role in skeletal muscle fibrosis, and this literally paints a picture that shows myostatin also has a role in this process. They then performed eight different in vitro tests to determine the relationship of TGF-B1 and myostatin. They essentially found that each one promoted the action of the other.
A previously known TGF-β1 inhibitor was then introduced to the study. They wanted to see if this TGF-β1 inhibitor known as decorin, would also inhibit or decrease myostatin fibroblast (fibrosis) proliferation, or growth. They found that decorin significantly decreased the effect of myostatin on fibroblast growth. To go a step further, they tested it in mouse muscle cells to see if it could reduce the effect myostatin has on cell growth (or muscle hypertrophy). And again they found that decorin inhibited the effect of myostatin in muscle cells, creating larger muscle cells (myoblast differentiation). The authors go on to also find that decorin stimulates follistatin the popular myostatin inhibitor.
In conclusion the authors made the following statement:
In summary, our results suggest the following:
(i)MSTN stimulates the formation of fibrosis in skeletal muscle after injury,
(ii) TGF-β1 and MSTN up-regulate the expression level of each other, and
(iii)DCN is capable of inhibiting MSTN activity as it does for TGF-β1
The second finding is highlighted above for an important reason. If a natural TGF-β1 inhibitor were to exist, we could likely inhibit myostatin to some degree. In return, build bigger muscles. Well we happen to be in luck. ForeRunner Labs has released a product to their fans known as Ursol-XT. Ursol-XT contains a modified compound known as Ursolic Acid. Ursolic Acid is also a potent TGF-β1 antagonist (2). Meaning it prohibits TGF-β1 from binding to its receptor. The research has yet to test Ursolic Acid’s direct impact on myostatin, but as we previously illustrated decreasing TGF-β1, can inhibit myostatin to some degree. (3)
Now this effect may not be as powerful as injecting follistatin itself, but even the results of this practice have led to questionable results. More likely because of the stability and quality of the grey market chemical, that is currently available to bodybuilders. Because of this, the information discussed suggests that Ursol-XT will be the best legal option to decrease myostatin available to bodybuilders today.
References
1. Relationships between transforming growth factor-beta1, myostatin, and decorin: implications for skeletal muscle fibrosis. Zhu J, Li Y, Shen W, Qiao C, Ambrosio F, Lavasani M, Nozaki M, Branca MF, Huard J. Pittsburgh, Pennsylvania : J Biol Chem., 2007, Vols. Aug 31;282(35):25852-63.
2. Ursolic acid, an antagonist for transforming growth factor (TGF)-beta1. Murakami S, Takashima H, Sato-Watanabe M, Chonan S, Yamamoto K, Saitoh M, Saito S, Yoshimura H, Sugawara K, Yang J, Gao N, Zhang X. Japan : FEBS Lett., 2004, Vols. May 21;566(1-3):55-9.
3. Role of TGF-β signaling in inherited and acquired myopathies. Burks TN, Cohn RD. Baltimore, MD : Skelet Muscle., 2011, Vol. May 4;1(1):19.