Myostatin is a human growth factor that prevents excessive muscle growth, and abnormally high levels can cause the loss of muscle mass. Despite the lack of proper data, myostatin has become a hot topic among athletes and bodybuilders, who claim that inhibiting it can boost muscle growth. Read on to learn what the latest science suggests myostatin inhibition might do.
What is Myostatin?
In both humans and animals, myostatin is a hormone that acts as a sort of “brake” that tells muscles to stop growing, which helps to prevent them from getting too large.
This is important because past a certain size, adding more mass to muscles doesn’t actually make them stronger – and muscles that are too large are also more vulnerable to damage. Over-developed muscles can also get in the way of other important organs, reducing their size and impairing their functions [1, 2].
Myostatin is active during multiple stages of the life cycle. Before birth (during embryonic development), myostatin determines the total number of muscle fibers an individual will have. In adults, myostatin controls the way that existing muscle fibers grow based on diet, physical activity, and age [3, 4, 5].
Scientists believe that exercise directly impacts myostatin levels – especially resistance exercise that specifically focuses on increasing muscle strength [5, 6].
In humans, myostatin levels also often increase with age, which may contribute to the loss of muscle mass during aging .
Myostatin levels are significantly higher in patients with diseases like amyotrophic lateral sclerosis (ALS), Duchenne muscular dystrophy, and multiple sclerosis, which all involve the significant loss of muscle mass. Therefore, inhibiting myostatin is an active area of research with the potential to help prevent the loss of muscle in these diseases [7, 8].
The FDA recently granted Orphan Drug Status to SRK-015, a myostatin inhibitor, for spinal muscular atrophy. This drug is intended to improve muscle strength and motor function in people with spinal muscular atrophy. SRK-015 is currently undergoing phase 2 clinical trials .
Myostatin is produced by the muscle tissue of the heart, and damage to the heart causes it to be released into the bloodstream. Once in the bloodstream, myostatin reaches the muscles and causes them to weaken over time. As a result, patients with heart disease often also experience symptoms of muscle atrophy (muscle loss) .
Scientists recently suggested that knocking out the genes responsible for producing myostatin in the heart prevented heart-disease-related muscle damage in mice, suggesting that myostatin inhibition might play a role in preventing muscle damage in humans with heart disease. Clinical trials to confirm this hypothesis have not yet been carried out .
What Does Myostatin Inhibition Do?
Below is a list of pathways myostatin inhibition may target, based on the available research. These findings should not be interpreted as supportive of any medical use or therapeutic benefit since no myostatin inhibitors have yet been approved as drugs anywhere in the world.
1) May Prevent Muscle Degeneration
Inhibiting myostatin might affect muscles in several different ways.
First, some evidence suggests that inhibiting myostatin can prevent muscle from weakening during long periods of inactivity. For example, myostatin inhibition reduced the loss of muscle in young mice that were prevented from using their hind legs for 21 days .
Secondly, scientists consider that myostatin inhibition may also prevent muscle loss that happens as a result of other diseases. For example, deleting the genes involved in producing myostatin in the hearts of mice prevented the severe muscle and weight loss caused by heart failure .
In mice with chronic kidney disease, inhibiting myostatin slowed the muscle loss caused by kidney disease and enhanced the growth of forearm muscles .
Over 20% of cancer deaths in human patients is caused by cachexia, a symptom of cancer that causes the loss of muscle and fat despite adequate nutrition. Some studies in mouse models suggest that myostatin inhibition may prevent cancer-related muscle loss in both lung and skin cancer (melanoma). This suggests that inhibiting myostatin should be further researched for preventing catexia-related cancer deaths in humans [13, 14, 15].
Duchenne muscular dystrophy (DMD) is an incurable disease that causes the loss of muscle tissue. Myostatin inhibition has been shown to increase muscle mass in dogs and mice with DMD, suggesting that the potential of myostatin inhibitors should be investigated in human patients with DMD [7, 16].
Additionally, myostatin inhibition prevented muscle weakness and muscle loss in mice with Huntington’s Disease, an inherited genetic disorder that causes muscles to degenerate over time .
2) May Help Build Muscle
A case study of a human child with unusually high levels of muscle development reported that the child also had very low levels of myostatin. The authors suggested that myostatin inhibition may have been involved in the observed enhanced muscle growth, though no other similar cases have been reported .
A pilot study using compounds that inhibit or decrease myostatin levels suggested that 7 days of treatment increased grip strength in 6 middle-aged human subjects. The authors suggested a link between myostatin and muscle development in healthy humans, though proper clinical trials are needed to confirm their hypothesis .
Inhibiting myostatin in healthy adult mice increased general muscle mass and grip strength, suggesting that myostatin continues to regulate muscle size throughout adulthood [3, 19].
Similar connections have been observed in mice and cattle, where genetic mutations that impair the creation of myostatin in the body result in “double-muscled” animals that have up to 20% more muscle fibers than normal, as well as dramatically reduced levels of body fat [20, 21, 22, 23].
However, persisting concerns have been raised regarding the long-term effects of myostatin inhibition (like muscle imbalance and respiratory disease risk) based on its impact on livestock and experimental animals. Some researchers think that there are no easy and quick answers to these concerns, which need to be carefully addressed in future clinical trials [24, 25].
3) May Reduce Fat Gain
Inhibiting myostatin may reduce the accumulation of fat in the body. This effect has mostly been seen in animal studies on follistatin, a natural hormone that inhibits myostatin [26, 27, 28].
In mice, using follistatin to inhibit myostatin led to reduced fat gain, and also decreased the size of fat-storing cells (adipocytes) .
Some scientists think myostatin inhibition should be further researched for potentially preventing obesity and diabetes [29, 26].
Foods and Supplements that May Inhibit Myostatin
Some people claim that myostatin can be inhibited in humans by taking supplements and eating foods that are rich in nutrients that can indirectly affect myostatin activity in the body. However, this approach remains purely anecdotal and theoretical since clinical data are lacking.
Talk to your doctor before taking any supplements or making major changes to your day-to-day routine. Remember that the best way to maintain muscle mass safely is to engage in regular exercise, eat a nutrient-dense and healthy diet that contains enough protein, and get enough rest and recovery.
Creatine is one potential myostatin inhibitor. Added to resistance training, creatine can increase the growth potential of muscles by lowering myostatin. In one study on healthy 27 men, creatine prevented increases in myostatin. Some researchers believe this may add to its muscle-building potential in power athletes .
Another talked-about method of inhibiting myostatin is through the consumption of epicatechin, a member of the flavonoid family of chemicals that control pigmentation in plants .
In old mice, daily injections of epicatechin led to increased overall muscle strength. The same treatment in 6 human subjects increased their hand grip strength after just 7 days. It’s impossible to draw valid conclusions from these studies, however .
On the other hand, epicatechin can be found in many healthy foods, including [32, 33]:
- green tea
- chocolate (especially dark chocolate and raw cocoa powder)
- broad beans
Eating these foods is an easy and nutritious way to support well-being. Whether or not these foods will affect myostatin inhibition is much less certain .
Despite the lack of evidence, certain companies claim their workout supplements also act as myostatin inhibitors.
Some “supplements” contain follistatin, an experimental compound being studied for blocking the actions of myostatin. Human studies about the effects and safety of follistatin are lacking .
One workout supplement that contains follistatin is MYO-X, which uses follistatin from fertile egg yolks. MYO-X was found to increase muscle mass in 37 healthy college-age male athletes when taken at 10 to 30 grams per day .
Creatine and follistatin supplements have not been approved by the FDA for medical use. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing.
Potential Side Effects of Inhibiting Myostatin
Despite the lack of safety data, myostatin inhibitors have become popular athletic supplements to use for purported fast muscle growth .
However, there are several potential downsides to myostatin inhibition in people seeking athletic enhancement.
The first concern is that no clinical trials have been carried out. Observational studies are equally lacking. We currently don’t know what the long-term effects of myostatin inhibition – and various purported myostatin inhibitors – in healthy people may be.
Another potential concern is that increased muscle growth will lead to an increased risk of injury due to increased stress on the muscle fibers. This may be especially true for individuals using myostatin inhibitors as workout supplements instead of as part of a medical treatment for muscular dystrophy or other disorders .
Other possible side effects of myostatin inhibitors include increased the chance of tendon rupture, heart failure due to inflamed cardiac muscle, and rhabdomyolysis, a breakdown of muscle fibers that often leads to kidney failure [38, 39].
Myostatin Inhibitors in Sports
The Dangers of “Gene Doping”
Aside from the fact that the athletic community views myostatin inhibition as cheating, the scientific research about its adverse effects for athletic enhancement is sparse. Various purported myostatin inhibitors could turn out to be dangerous with more research .
One way people think they can inhibit myostatin is through “gene doping,” where human DNA is directly altered to grow muscle more easily. This is often done in secret due to its worldwide ban, since “gene doping” may have serious health consequences we know nothing about .
“Gene doping“ should be strictly avoided. It can have potentially life-threatening and unpredictable consequences.
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Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice from your doctor or another qualified healthcare provider because of something you have read on SelfHacked. We understand that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.
While there are many different ways to use supplements and foods to influence myostatin levels, most of the user experiences on the net come from athletes who have used supplements like MYO-X to enhance their muscle growth:
“Unfortunately, this product does not perform what it claims. I took this product for two months and noticed no increase in strength or muscle mass when taken every day with proper diet and workout routine.”
“I can’t stress enough that the effects of Myo-X really demand added protein/nutrition above and beyond what you may already be used to…insufficient building blocks equals little benefit, and Myo-X is helping direct more bodily resources to muscle. This is the best product for bodybuilders or those who love bodybuilding.”
“I have been taking MYO-X for more than a year. Together with regular exercise, it helps to keep my body in shape.”
“MyoX definitely takes my workouts to the next level! Remembering to take it the night before morning training is the only reason it’s not a 10!! At 47, I’m no stranger to the supplement game and saying that using MyoX over the past few years, it’s quite obvious that it’s a game changer!”
“Myo-x has 100% helped my soreness levels and I no longer have to ice my shoulder after every workout. My training volume has gone up greatly since taking it and consequently, my strength.”
“I tried it and it helped my gains a lot. Saw results a lot quicker than before and with the right diet you will see gains easy!”