Subtitles section Play video Print subtitles We all have a fascination with muscles and strength - whether we want to be stronger, feel better, or look like superman; and there are many proposed strategies and exercise regimens to get this done. But what if I told you that it was out of your control, and that your genetics may be entirely holding you back? Conversely, what if there was a secret out there that could lead you to super human strength? The truth is: your muscle size has a limit. Sure, it may seem obvious when you hear it, but your muscles are under the strict control of a protein called Myostatin, which determines exactly how large a muscle can become. And this limit is different for everyone depending on their myostatin levels. As a muscle reaches this limit, myostatin prevents any further growth. But if the myostatin itself is limited or absent, this muscle limit suddenly goes away. This phenomenon was first noticed in Belgian Blue Cattle. These cows developed 2-3 times more muscle mass than a normal cow, and it was later discovered that they had a deletion of the gene GDF-8, which just so happens to create myostatin. As a result, without any exercise or special diet, these cows have incredible muscle mass. Similar cases have been documented in dogs, mice, and even a few cases of human babies lacking the GDF-8 gene. These findings have helped scientists understand why some people bulk up easily, while others struggle to. Lower levels of myostatin = more muscle mass. In fact, some studies have even shown that many champion body builders have naturally lower levels, or even entire deletions of the myostatin gene. If you look at somebody like Arnold Schwarzenegger, as a teen, he just looks naturally muscular. As such, perhaps many champion bodybuilders owe their success more to genetics than their training or drug use. Eventually, it may be possible to develop drugs which deplete or block myostatin. Of course, it's a double edged sword; On the one hand, patients with muscular dystrophy, or muscle loss from aging could regrow and restore muscle. On the other hand, the potential for abuse as performance enhancers seems...inevitable. But, the prospect of seeing a real-life human Hulk...seems kind of cool. Besides, should those who already have low levels of myostatin be considered to have an unfair advantage? It's hard to say. Regardless, be weary of anybody selling or promoting this unproven and unregulated treatment. At the end of the day, whether you have naturally low or high myostatin levels, remember - this is the level that is optimal for your mechanical and metabolic efficiency. With proper exercise and general health, you'll reach your own unique physiological peak. And while you may not be destined to pack a punch like Superman, you can push your own limits through training and hard work. But, what if you could punch as hard as Superman? Our friend Jake over at Vsauce3 has the answer to this smashing superhero question, which you definitely need to check out. And if you want to know how much myostatin you have...there's only one real way to find out. Get working. This episode of AsapSCIENCE is supported by 23 and Me. 23 and Me is a DNA analysis service that allows you to explore your own genes. Whether you are interested in discovering your global origins, or understanding your health and your risk for disease, be sure to check out 23andme.com/asap. With the help of their DNA kits, connect to your past, learn about your present health and potentially be part of future genetic research, all at 23andme.com/asap. And subscribe for more weekly science videos.