YK-11 Myostine SARM: Benefits, Uses, Dosage

YK-11 is the most powerful SARM available for increasing muscle mass. It has steadily risen in popularity among the bodybuilding community within recent years due to its myostatin inhibiting ability.

In this article, I’ll reveal exactly what you need to know in order to make an informed decision on whether or not to use YK-11 in order to achieve your fitness goals.

Warning: The content on Muscleandbrawn.com and the information included in this article is intended for entertainment and informational purposes only. It is not intended nor implied to be a substitute for professional medical advice. Prior to buying anything, check that it is compliant where you live with your current government laws. We frequently mention research chemicals that are not made for human consumption. Therefore, before purchasing any product for personal use, consult with your doctor or healthcare provider first.

What is YK-11?

YK-11 is a selective androgen receptor modulator. As such, it is able to selectively attach to specific androgen receptors, rather than invading your body in a shotgun approach like anabolic steroids. [1]

YK-11 is able to inhibit the activity of myostatin, which is a protein that prevents muscle growth. This makes it an effective compound to take during cutting as it will help to prevent muscle loss.

YK-11 has a geometric structure that is very similar to anabolic steroids. Some people actually believe that it is a synthetic steroids that has been mislabeled as a SARM.

Where to Buy YK 11

YK 11

YK 11

YK11 is a synthetic steroid categorized as a Selective Androgen Receptor Modulator (SARM), engineered to selectively engage androgen receptors in skeletal muscles and bones, closely emulating the anabolic effects of testosterone with minimized systemic side effects associated with conventional anabolic steroids. This specificity is what renders YK11 particularly intriguing for both therapeutic applications and bodybuilding endeavors.

A primary advantage of YK11 lies in its ability to substantially enhance muscle mass and strength by promoting more efficacious muscle cell growth than endogenous testosterone, facilitating users in achieving fitness objectives more swiftly. Furthermore, YK11 is postulated to positively impact bone health by augmenting bone density, offering potential benefits in the prevention of fractures and osteoporosis.

Distinctively, YK11‘s action mechanism encompasses the inhibition of myostatin, a growth differentiation factor that plays a critical role in regulating muscle mass. Inhibition of myostatin by YK11 could theoretically allow individuals to transcend their genetic limits in muscle development. This characteristic of YK11 is of particular interest to the scientific community and fitness enthusiasts aiming to maximize muscular gains.

Notwithstanding its promising attributes, it is paramount to acknowledge that YK11, akin to all SARMs, is still in the investigational phase, and its comprehensive safety profile remains undetermined. Prospective users should exercise caution, mindful of the potential for adverse effects and the current absence of regulatory endorsement for human application.

YK 11 Overview

⭐️ Top Benefits: Enhanced muscle mass and strength, bone density improvement, potential for myostatin inhibition allowing surpassing genetic muscle growth limits
πŸ§ͺ Form: Oral tablets
βŒ›οΈ Cycle Length: 8 Weeks
πŸ’° Average Cost: $64.99
β€οΈβ€πŸ©Ή Side Effects: Potential for liver toxicity, changes in cholesterol levels, hormonal imbalances
☒️ Dangers: Lack of long-term safety data, potential for significant endocrine disruption
πŸ“š Best Stack: Cardarine / LGD 4033 / RAD 140
PCT Required: Debate exists; some suggest PCT to mitigate endocrine system impacts, though not universally agreed upon
πŸ§β€β™‚οΈπŸ§β€β™€οΈ Men/Women: Primarily used by men due to the risk of virilization in women; women should proceed with caution if considering use
➑️ Go to the Full review

  • Estrogen regulation
  • Hormonal Balance in PCT
  • Prevention of Gynecomastia
  • Joint Pain
  • Fatigue
  • Bone Density Concerns

How Does YK-11 Work?

The protein myostatin impairs the body’s ability to build muscle and get stronger, whereas another protein follistatin promotes muscle and strength gains. When you take YK-11 you lessen the levels of myostatin and increase those of follistatin.

Studies have shown that people with a mutation that limits myostatin production are both more muscular and stronger than those with normal amounts. YK-11 may help to inhibit the levels of myostatin in muscles by attaching to the androgen receptor.

From there, it appears to induce muscle cells to create more follistatin, which in turn limits the levels of myostatin and allows for muscle growth beyond your genetic capability. [2]

Benefits of YK-11

YK-11 is recognized by many users as the best SARM for building muscle. Its mass building potential means that YK-11 is effective in all three types of stacks – bulking, cutting, and recomping.

YK-11 has also been shown to significantly increase strength levels. Some users have been able to increase their one-rep max on compound lifts by as much as 40 pounds over the course of an 8-week cycle.

Research has also shown that YK-11 is able to strengthen bones since it increases the levels of Protein Kinase B, which is involved in the growth of bone cells.

Finally, YK-11 may be similar to testosterone in its ability to promote muscle growth

YK-11 Usage in Bodybuilding

YK-11, one of the potent SARM, works by increasing the levels of follistatin and inhibiting myostatin. Follistatin is known to promote muscle growth and strength, whereas myostatin does the opposite. Thus, by binding to the androgen receptors of skeletal muscles and promoting the release of follistatin, YK-11 induces muscle growth and therefore aids in the process of bodybuilding. For bodybuilding, the recommended dose is 10-15 mg/day.

Is YK-11 Legal?

YK-11 is legal to purchase in every country throughout the world. You can buy it without a prescription in every country, except for Australia.

The Australians have classified SARMs as Schedule 4 prescription-only compounds. As a result, they can only be acquired with a doctor’s prescription. In other parts of the world, you can buy SARMs online, however, the sellers must only market them as research tools.

YK-11 and all other SARMs are listed as banned substances by the World Anti Doping Authority (WADA). It is similarly listed as banned by the US Anti Doping Agency.

Who Should Use YK-11?

YK-11 is a potent SARM that should not be used by first-time users of selective androgen receptor modulators. It is best to start your first cycle with a milder SARM, such as Ostarine, and then work your way up to more potent SARMS over a series of cycles.

No person who is still undergoing puberty should take any SARMs. Instead, you should allow your body’s natural growth spurt and huge release of growth hormone and testosterone during these years to take their natural course.

You also need to be training consistently and intensely with weights as well as dieting diligently if you want to benefit from YK-11.

YK-11 Cycle

The most effective and safest YK-11 cycle appears to be between 10 and 15 mg per day taken over an 8-week cycle. However, if you are running your first YK-11 cycle, we recommend being a little more conservative with just 5 mg per day over 8 weeks.

YK-11 Dosage

The recommended dosage for running an 8-week cycle of YK-11 for mass building is between 10 and 15 mg per day, depending on your bodyweight. People under 200 pounds should take 10 mg per day, while those who weigh in excess of 200 pounds should take 15 mg per day.

If you are running your first cycle with YK-11 or taking it as part of a cutting or recomp stack, we recommend taking 5 mg per day.

YK-11 For Bodybuilding

YK-11 is an extremely popular SARM for bodybuilding as it meets every need from bulking to cutting and even recomping. Due to its ability to inhibit myostatin and encourage follistatin production, it is an extremely powerful muscle and strength booster.

When it comes to cutting, YK-11 will not actually help you lose weight. However, it will prevent muscle loss while you are going through your fat loss cycle, which is why it should be included in your cutting stack.

When taking Yk-11 for mass building, we recommend using a dosage of between 10 and 15 grams per day based on your body weight.

Run your cycle for 8 weeks, with a four week PCT of 20 mg of Clomid per day. Your PCT cycle should begin at the beginning of your last week of the cycle.

YK-11 For Cutting

YK-11 is not a cutting agent, however, it is popularly used within cutting stacks due to its ability to preserve muscle mass while you are losing body fat.

We recommend the following cutting stack:

  • Week 1 – YK-11 – 10 my per day / Stenabolic – 10 mg per day / S23 – 10 mg per day
  • Week 2 – YK-11 – 10 my per day / Stenabolic – 10 mg per day / S23 – 10 mg per day
  • Week 3- YK-11 – 15 my per day / Stenabolic – 15 mg per day / S23 – 10 mg per day
  • Week 4- YK-11 – 15 my per day / Stenabolic – 15 mg per day / S23 – 15 mg per day
  • Week 5- YK-11 – 20 my per day / Stenabolic – 20 mg per day / S23 – 15 mg per day
  • Week 6 – YK-11 – 20 my per day / Stenabolic – 20 mg per day / S23 – 20 mg per day
  • Week 7 – YK-11 – 20 my per day / Stenabolic – 25 mg per day / S23 – 20 mg per day
  • Week 8 – YK-11 – 25 my per day / Stenabolic – 25 mg per day / S23 – 25 mg per day / Clomid – 20 mg per day
  • Week 9 – Clomid – 20 mg per day
  • Week 10 – Clomid – 20 mg per day
  • Week 11 – Clomid – 20 mg per day

YK-11 For Women

Women can use YK-11 but they need to so in far more conservative dosages than men since they produce androgens in far smaller amounts. As a result, they should only use YK-11 in dosages of between 0.5 and 2 mg per day.

YK-11 is one of those that are best suited for women because of its relatively low androgenic effects.

YK-11 Stack

Beginner users of YK-11 should not stack for the first cycle, running it singly at a dosage of 5 mg per day for eight weeks.

In addition to the stacks that we have already covered, YK-11 also stacks well with the following compounds:

  • MK 677
  • Cardarine
  • SR9009

YK-11 Side Effects

Although YK-11 does not result in the negative effects to your organs that are common with the use of anabolic steroids, some users have experienced minor side effects. These include hair loss (though this comes back when you go off the cycle), acne (again, this goes away after your cycle), increased aggression, and decreased sex drive.

This last effect is a result of the testosterone suppression that comes when you cycle YK-11. For that reason, you should also follow your YK-11 cycle with a 4 week PCT cycle, taking 20 mg of Clomid per day.


You should follow your YK-11 cycles with post cycle therapy as this will counter the testosterone suppression effects of your cycle which can lead to lowered virility, energy, and general well-being.

I suggest that you begin your first week of PCT during the last week of your cycle and continue it for four weeks. Your PCT cycle should involve taking 20 mg of Clomid per day.

Does YK-11 Work?

Yes, YK-11 most definitely works. Both clinical research and anecdotal evidence from users suggests that, as long as you are training hard and eating smart, you can put n between 5 and 9 pounds of lean mass over the course of an eight-week cycle.

Is YK-11 Safe?

When taken at the dosages that I have recommended in this article, YK-11 is safe. However, a few people have noted minor side effects such as hair loss and acne.

Thankfully, these side effects go away once a person has finished their cycle. If you do not follow a PCT cycle, you will experience reduced virility and lack of energy.

Where to Buy YK-11

You can buy YK-11 from a large number of online retailers, however, you need to be very careful about purchasing SARMs online. We advise sticking to an established and respected retailer.

One of the best online retailers is Bio Science. This is an American company that has been operating since 2013.

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YK-11 vs RAD140

Testolone RAD 40 is a popular mass building compound. However, it cannot compete with YK-11’s ability to inhibit myostatin.

So, if you had to choose between these two SARMs for mass building, you will get better results with YK-11.

YK-11 vs S4

Anadarine S4 is yet another potent mass building SARM. Yet, it too, cannot compete with YK-11 in the lean bulking department.

However, the side effects that some people experience with YK-11, such as hair loss and acne, will not occur with S4. If you are not able to tolerate YK-11, you will do well to give S-4 a try.

YK-11 vs Ligandrol

Ligandrol is another powerful muscle and strength building SARM. Its mechanism of action is different than YK-11, as it does not affect your levels of myostatin or follistatin.

YK-11 vs Ostarine

Otsraine is considered to be the mildest SARM on the market. Therefore, it’s a great starting compound to run for your first cycle.

If you have no problems with it, you can then run a stronger SARM like YK-11 on your second run.

Start with a conservative dose like 5 mg per day over eight weeks. On your next cycle, you can take it up to 10 mg per day.

Should You Take YK-11?

If you have made up your mind to take some form of chemical enhancement to advance your muscle building and cutting efforts, then YK-11 is a good choice for you. Although it is much safer than using anabolic steroids, you should only take YK-11, or any other SARM, if you are beyond puberty, training intensely, and are following a muscle-building or cutting diet diligently.

If you can tick all of those boxes, then you can look forward to some pretty impressive results on YK-11!

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[1] Selective Androgen Receptor Modulators (SARMs): USADA. (2020, July 27). Retrieved from https://www.usada.org/spirit-of-sport/education/selective-androgen-receptor-modulators-sarms-prohibited-class-anabolic-agents/

[2] Yatsu, T., Kusakabe, T., Kato, K., Inouye, Y., Nemoto, K., & Kanno, Y. (2018). Selective Androgen Receptor Modulator, YK11, Up-Regulates Osteoblastic Proliferation and Differentiation in MC3T3-E1 Cells. Biological & pharmaceutical bulletin, 41(3), 394–398. https://doi.org/10.1248/bpb.b17-00748

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Steve Theunissen

Steve Theunissen | Writer

Steve Theunissen is a seasoned fitness professional with 25+ years of experience. He has multiple certifications from the International Sports Sciences Association, including Certified Personal Trainer, Fitness Nutrition Certification, and Strength and Conditioning Certification. He's a knowledgeable and experienced bodybuilding coach, combining his passion for fitness with his writing skills to educate and inspire. Whether starting out or looking to take training to the next level, Steve Theunissen is the ideal coach to help reach fitness goals.

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Chemical Structure

Mechanism of Action

Although Myostine binds to the Androgen receptors, it only partially stimulates them, and inhibits the activity of Dihydrotestosterone (DHT). It also increases the synthesis of muscle-building protein called follistatin.

Class of Compound


Street Names



  • Faster and better gains
  • Increases muscle strength
  • Improves vascularity

Side Effects and Dangers

  • Headaches, nausea, and stomach issues
  • Testosterone suppression
  • Liver toxicity

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