Myostatin, also known as growth/differentiation factor 8 (GDF-8), is a protein in humans and animals that regulates muscle growth. The myostatin protein inhibits excessive muscular growth. Myostatin is essential to the human body if it is to have a proper metabolism and retain homeostasis. It takes 50-100 extra calories a day to maintain just one pound of muscle. Imagine what would happen to our metabolisms if we had uncontrollable muscle growth? The body also needs to maintain a stable temperature and more lean mass means that the body’s cooling efficiency will drop. Large muscles also means that fibers are added closer to the tendon. These fibers work from a mechanical disadvantage, which may send the nervous system the message that this new, bigger muscle isn’t very efficient. So there are many reasons why myostatin is “good” for the human body. Muscle is also very expensive, genetically speaking, to synthesize. The body needs a very good reason to create and sustain muscle, which is why extreme muscular stress is needed to start the process.
Many universities and pharmaceutical companies are currently trying to develop drugs to inhibit myostatin or turn off the production of it in hopes of curing such muscle wasting diseases as muscular dystrophy, AIDS, and cancer to name a few. Researchers at John’s Hopkins University have been able to block the gene in mice, which caused these genetically engineered mice to grow to twice the size of normal mice without any extra food or training! A 1998 study showed that myostatin levels increased in HIV patients as their muscle tissue began to waste away. This shows us that myostatin is inversely correlated with fat-free mass. The most likely explanation of this is that the body constantly strives to maintain homeostasis.
Belgian Blue cattle are another example of what happens when the GDF-8 gene is blocked or non-existent. Cattle farmers had to figure out a way to get more product out of their livestock, so they selectively bred the most muscular cattle. Over time, the cattle grew to be 2 to 3 times the size of normal cattle! A scientist from Belgium discovered that these cattle lacked the myostatin gene, thus producing amazing amounts of muscle with no alteration to diet or physical activity.
Many supplement companies are now claiming that they have created a supplement that can block myostatin, which simply cannot be true. Scientists that are manipulating GDF-8 are doing so through embryonic microinjection, meaning that this gene is being manipulated before birth. Scientists at John’s Hopkins University have only recently discovered how to perform this procedure and it will likely be 5-10 years before any pharmaceutical companies can develop a suitable human friendly drug.
Victor Conte of BALCO fame, was able to prove that Flex Wheeler, perhaps one the most genetically gifted bodybuilders of all time, had a mutation in his myostatin gene, thus allowing him to grow extreme amounts of muscle. What does this mean for you and I? It means that everyone has their own unique level of myostatin suitable for our own bodies. This means that we may never achieve our dream level of muscle mass, but it does mean that our body has myostatin for a reason and as long as we train smart and hard, we will develop the most efficient muscular body we are capable of.