YK-11 Review

What is YK-11? Is it safe for health? What effects can you expect from using this product? What should you know before buying it? You will find answers to these and other questions in the article below.

What is YK-11?

YK-11 is a substance that accelerates muscle building. It is one of the newest products on the market. It was discovered in 2011 by Yuichiro Kanno. Currently, it is not very popular. The main reason is the lack of human studies and a very small number of animal ones. Often, for the sake of simplicity, it is included in the group of SARMs (Selective Modulators of Androgen Receptors). However, it is not SARM per se – just like the agents in this group it binds to androgen receptors but does not affect them. 

In reality, it is a myostatin inhibitor (it reduces its activity in the body). Myostatin is a protein that is responsible for inhibiting muscle development by blocking the formation of new muscle fibers and reducing the protein synthesis rate. The amount of this protein in our body not only determines our genetic limit but also influences the rate of gaining new muscles. 

To illustrate the importance of this protein, I will use examples of animal that was born with its deficiency as a result of genetic mutation.

miostatin cow

YK-11 Benefits

  • Accelerates muscle building
    YK-11 is one of the most potent anabolic substances legally available. Although it is not SARM (Selective Modulator of Androgen Receptors), at least in theory it shows very selective action.
    YK-11’s ability to accelerate muscle building is mainly a result of increased levels of follistatin. It is a protein that inhibits myostatin (its antagonist).
    However, if follistatin is somehow blocked in the body, its ability to affect myostatin will also be inhibited, and consequently, the use of YK-11 will be ineffective.
    Unfortunately, there are currently no reliable studies showing exact effects on humans or animals. Most studies have been conducted in vitro, so their reliability is quite limited.
    In fact, the only source of information about this measure is currently the reviews of bodybuilders using YK-11 appearing on forums, Reddit, etc.  Some of them claim that thanks to YK-11, they managed to burn a significant amount of fat and gain even up to 7kg (15lb) of fat-free mass.
  • Strengthens the bones
    The level of sex hormones in the body is crucial for healthy bones. Available evidence shows that YK-11 can strengthen bones by joining their androgen receptors.
    YK-11 also increases the amount of active GDP (Protein kinase B) that accelerates bone growth.
    Strong bones are essential not only from a health perspective but also in the context of muscle building. Studies show that people with larger bone diameters have higher genetic limits, more muscle fibers, and more easily maintain the acquired muscles.
  • Increases the genetic limit
    As mentioned at the beginning of this article, YK-11 reduces myostatin levels in the body by increasing the amount of follistatin. Myostatin level is the main factor inhibiting muscle development after crossing a certain threshold. 

Side Effects

First of all, it is important to mention that any side effects are dose-dependent. Because of the small number of reliable data sources, YK-11 testers often had to choose a dose based on trials and errors, which may have increased the number of negative reviews. 

Usually, SARMs do not cause significant side effects due to their selective effect on androgen receptors. However, YK-11 is such a powerful agent that it is different in its case. 

It seems that YK-11 somehow makes the receptors more sensitive, increasing their androgenic effects. Many users have complained about increased aggression in doses as low as 10mg per day. According to some of them, YK-11 can cause an increase in blood pressure.

Moreover, a large number of testers claim that YK-11 can cause testosterone suppression. For this reason, it is advisable to have PCT before you start your cycle. 

There is no confirmed information on the effect of YK-11 on the liver so far. One of the youtubers decided to use YK-11 in high doses for one week with excellent results. Check his Vlog on youtube:

In the video, he reveals that he was taking YK-11 in such high doses to check if it was hepatoxic. After analyzing the results before and after you can conclude that it is not. 

YK-11 blood lab results

YK-11 Results

On forums or Reddit we can find a lot of threads describing experiences with YK-11 and results achieved. Unfortunately, many of them come from untrusted users with only a few posts. Moreover, it should be remembered that only a few vendors are selling good quality SARMs. Most of the substances of this type that we find on the market have little to do with the label. Often instead of SARMs in products, we can find steroids or prohormones. For this reason, it is difficult to find reliable information on this product. 

However, I was able to find two topics that had been created by long-time users, in which they described their experiences and provided a source of purchase that I consider trustworthy. 

I used YK-11 for 6 weeks in a dose of 5mg per day. I decided to use a low dose because I wanted to see how strong this substance is, and I was a little afraid of side effects. With such a dose, I did not experience any side effects. I ate about 500kcal above the calorie requirement.

He also posted his results:

YK-11 results

Review of another user who used a dose of 10mg/day:

During the cycle, fatigue was clearly noticeable. The effects of the YK11 were already visible at the end of the first week. Both strength and weight went up significantly, although I did not pay much attention to diet and training. During the last week of the cycle, I had pain in my joints, especially in my knees. I think I’ll be returning to this substance again, but probably in a smaller dose and in combination with other SARMs.

My opinion

To be honest, I’m not a big fan of this substance at the moment. I haven’t used YK-11 so far due to too little research, so it’s hard for me to say anything about the results you can get. I think that at this stage, it is better to try other sarms, the action of which is quite well known (Ostarin, RAD-140, LGD-4033, etc.). 

Yk-11 before and after

These photographs show the true potential of YK-11. If their authors used only YK-11 as they declare, it may turn out that in the end a relatively safe agent with a strength similar to that of steroids was created. Unfortunately, at the moment, we do not know the exact effects of this substance, so all information should be treated with a pinch of salt. 

YK-11 Dosage

Again, there is too little data for me to make any specific recommendations with a clear conscience. 

On the basis of current users’ experiences, 5mg for a maximum of 6 weeks seems to be a dose that avoids side effects, and I would stick to this dose. If you are not satisfied with the results, you can combine YK-11 with other SARMs such as Ostarin or LGD-4033.

Where to buy YK-11?

Unfortunately, due to the high price of SARMs in wholesale, most of the products on the market are of low quality. According to some reports, more than half of the products have less substances than declared on the label. To enhance their effect, steroids or prohormones are added instead of SARMs. For this reason, SARMs should be purchased only from reliable sources that have a certificate of analysis for each product.

Proven Peptides

proven peptides logo

The only seller I can recommend that has in offer YK-11. It is currently the most popular shop selling SARMs in the world. Offered products are of excellent quality and are reasonably priced. They offer SARMs only in the form of solutions. Each bottle comes with a pipette and information on how many drops corresponds to the recommended dose of the substance. On the website, there is a phone number so that any doubts could be solved within a few minutes. They offer a loyalty program “Peptide Points” in which you can exchange your points for discounts on further orders. Shipping from the USA.

Link to Proven Peptides website


Although it has been our favourite shop for a long time, we are forced to change our recommendation. In recent months, contact with them has become difficult, parcels are delayed, and there is a lot of negative feedback on the effectiveness of their products. I apologize to all the people who bought their products in recent months based on my recommendation. 

Frequently Asked Questions

What is yk11 half-life?

Unfortunately, there is very little information about this drug. The exact time of half-life is still not known. The opinions of users suggest that it is quite short, so the daily dose should be divided into several portions in order to maintain a stable level of the substance in the blood. If you decide on a dose of 10mg, dividing it into 2x5mg should be sufficient. 

yk11 vs rad-140

Both of these substances, in theory, are very strong. For those who are not yet close to their genetic maximum, I would suggest to start with RAD-140

Does yk11 cause hair loss?

Unfortunately, no human studies have been conducted yet, so the exact side effects are not known. In individual cases, users have complained about increased hair loss. 

Is yk11 legal?

At the time of writing this article, YK-11 is legal in the USA and most countries of the world. However, it is on the WADA list, which means that it cannot be used by professionals.