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Ostarine (MK 2866) Review, Results, Dosage | April 2024

Table of Contents

This is the ultimate guide and review of Ostarine, also called MK 2866 or Enbosarm. In this guide we will go over everything that you should know about Ostarine, including:

  • What is Ostarine and how does it work
  • Ostarine legality
  • Benefits and side effects
  • Where to buy high-quality, pure Ostarine
  • PCT, dosages, cycle length, results
  • Lots, lots more

Ostarine (MK 2866) Review

If you’re in a rush you don’t have time to read this in-depth guide, check out this YouTube video. It’s not as in-depth but it goes over the important things about MK 2866.

For those of you who just want to know which are the companies that sell high-quality, pure Ostarine:

Recommended, Verified Ostarine Sources

Let’s start off by explaining what Ostarine actually is and how it works.

What Is Ostarine

Ostarine, also called MK 2866 or Enbosarm is a SARM – Selective Androgen Receptor Modulator. This means that it selectively targets our androgen receptors. More on that later.

Ostarine molecule structure

Some of the benefits of Ostarine are:

  • Increased muscle mass
  • Decreased body fat
  • Strength increase
  • Healing properties

We will go over all of Ostarine benefits later in the article.

How Does it Work

All SARMs work very similarly and for the most part, differ from each other in strength.

Ostarine is one of the mildest, safest and most researched SARMs, but even though it’s the mildest, it can give great results.

It is designed to selectively target the androgen receptors in our bodies. It selectively aims the androgen receptors, which means it reduces unwanted side effects such as increased prostate size or major hair loss.


Steroids, on the other hand, are not selective and therefore cause a lot more side effects and are a lot more dangerous.

So SARMs have similar effects of steroids but they are much cleaner and with little to no side effects. Of course, steroids are much stronger in comparison to Ostarine but some SARMs like YK11 can compare themselves to steroids.

And while there are still possible side effects to using this compound, they are very few and very mild.

History Of Ostarine

Ostarine, also called MK 2866 or Enbosarm, was developed by GTx Inc. in 1997 to treat muscle wasting diseases and osteoporosis.

In 2007, Ostarine was already in Phase 2 of clinical trials.

In 2011, there were many Ostarine human trials. One of the studies that focused on elderly men proved that Ostarine resulted in a significant increase in lean body mass.

In 2016, Ostarine failed phase 3 clinical trials for treating muscle wasting diseases in people with lung cancer. Ostarine almost successfully completed these trials. It failed because people with lung cancer were too weak to use Ostarine.

As of right now, Ostarine is still in development. It’s successfully going through numerous clinical trials to one day treat muscle wasting diseases.

Is Ostarine Legal

As of 2024, Ostarine is completely legal in every country in the world except for Australia. We will cover the Australian MK 2866 legality later in this article.

If you aren’t from Australia, however, you won’t have any problems buying or using MK 2866.

You can read more about the legality of Ostarine in my article on the legality of SARMs where we cover every country.


In Australia, Ostarine (and other SARMs as well) is considered to be a Schedule 4 prescription compound by the TGA.

So basically, if you don’t have a doctor’s prescription for MK 2866, you aren’t allowed to use it. Still, a lot of Australians use MK 2866 and other SARMs.

If you get caught, you can get up to 4 months of a prison sentence. I haven’t seen anybody actually go to prison for using SARMs though.


Selling Ostarine in Australia is a different story. They take it a lot more seriously than if you just buy and use it.

If you are just buying and using MK 2866, you almost certainly won’t have any problems. If you are selling it, however, and you don’t have the permission to sell SARMs in Australia, you can get fined up to $1 million.

For more information about this subject, read my article on SARMs in Australia.

Professional Sports

It’s important to know, however, that Ostarine, as well as the other SARMs, are prohibited in competitive sports.

Ostarine is listed as a banned substance by almost all sports bodies including the Olympics as well as organizations such as:

  • USADA (U.S Anti-Doping Agency)
  • WADA (World Anti-Doping Agency)
  • ASADA (Australian Sports Anti-Doping Authority)

This is because of the obvious unfair advantages that this compound provides such as increased strength, muscle, and endurance.


Please don’t use MK 2866 or other SARMs if you are a professional athlete.

MK 2866 is detectable on tests that detect SARMs. You will get caught for using it if you get tested for it and you have been using it in the past 10 days. If you take a break from using it for 10 days, however, you won’t test positive for Ostarine because it will be out of your system by then.


Ostarine is one of the most popular and widely used SARMs, which means that it is also one of the most extensively tested. There is also a lot of research and study about this compound and its benefits.

Some of Ostarine Benefits

Muscle Bone CNS
Increased muscle mass Aid in bone formation Improved cognition
Increased strength Increased bone strength Increased libido
Improved bone resorption Boosted energy levels

We will go in-depth over the most popular benefits such as:

  • Increased muscle mass
  • Strength increase
  • Lower body fat
  • Keeping muscle and strength on a cut

Increased Muscle Mass

Ostarine has shown in both clinical trials and personal experience to increase muscle mass even when on a cut. This means that even when we are in a caloric deficit we will still build some lean muscle while losing fat.


You can also take Ostarine on a slight bulk to gain even more lean muscle mass.

According to the picture above that was taken from human trials, Ostarine showed great results in increasing muscle mass even at low dosages of 3mg a day.

In 12 weeks, the test group who were taking MK 2866 at 3mg a day managed to get 3 lbs of lean muscle mass more than the placebo group. This is with the same training and diet. Keep in mind that 3mg a day is considered a very low dosage.

I recommend that you consider RAD140 or LGD 4033 if you want to gain as much muscle mass as possible. They are a lot better than Ostarine in doing that.

Recommended, Verified Ostarine Sources

MK 2866 is definitely a cheat code when it comes to gaining muscle, but it’s very mild compared to some other SARMs. The great thing, however, is that it’s very researched and it’s considered to be a very safe compound.

You can expect to get 2 lbs of muscle on a cut or 6lbs of muscle on a lean bulk.

Keep in mind that your diet and training will still be very important.

Increased Strength

Ostarine, like other SARMs, also gives a great benefit of increased strength.

You will notice your strength going up every week even if you are cutting. Usually, the strength increase becomes noticable in about 2-3 weeks of using MK 2866.


You can expect to see quick improvement in your lifts, especially if you are a beginner.

This compound is also great for breaking through strength plateus that you’ve been stuck on for a while.

Fat Loss

Ostarine is very good at promoting fat loss while building muscle. This means that this compound is a great choice if you want to do a body recomposition which means that your weight will stay the same but your muscle to fat ratio will drastically improve.


In my opinion, MK 2866 is the best and safest solution for losing fat while gaining muscle, I also like to stack it with Stenabolic or Cardarine for optimal results.

Keeping Muscle On A Cut

Ostarine is known for the amazing benefit of keeping muscle mass and strength on a cut. A lot of the time, depending on your training and diet, MK 2866 increases your muscle mass and strength on a cut.

This isn’t suprising because this compound was developed to battle against muscle wasting diseases.

What a lot of people do is they first bulk up and gain a lot of strength and muscle mass. After that, they cut with Ostarine which makes it easy for them to keep all of the strength and muscle.

Side Effects

Ostarine, like most other compounds, isn’t completely perfect. The main side effect is:

  • Suppression of your natural production of Testosterone

Let’s dive into this “side effect” in more detail.

Testosterone Suppression

As we said, MK 2866 will suppress your natural production of Testosterone.

Keep in mind, however, that the suppression from this compound, assuming that it’s real and high-quality, will be very mild and barely noticable. Most people don’t even notice it and even if you do, your body will naturally recover in a few weeks after the cycle.

You could artificially help your body recover by doing a post cycle therapy protocol (PCT) but that may not be so smart, more on that later.

Remember to stick to normal dosages and cycle length to make sure that the suppression will be as low as possible. Most importantly, make sure that you buy high-quality, pure MK 2866.

Some companies will sell bunk products that are spiked with other substances. Because of this, these products can be very suppressive. Real Ostarine, on the other hand, is very mildly suppressive.

Other Side Effects

Some people who use this compound also report other side effects such as:

  • Bad sleep
  • Joint pains
  • Hair shedding

Even though there have been a lot of Ostarine studies and human trials done, none of them showed any of these side effects.

With that being said, there are two possible explanations for people experiencing these side effects.

The first one is that the MK 2866 they used was bunk and spiked with other substances which caused these side effects to happen. Sadly, the market is full of bunk products like these.

In my opinion, if you experience weird side effects like these with a compound like Ostarine, it’s almost 100% bunk.

The second possible explanation is that these “side effects” are an individual thing. Everybody reacts differently to compounds like MK 2866. A small minority may experience side effects such as bad sleep. But if you ask me, if you see these side effects, your SARMs are probably bunk.

Ostarine Vs Steroids

Ostarine Steroids
Build Muscle Build Muscle
Shred Fat Shred Fat
Low Side Effects Medium to high Side Effects
Low Aromatization High Aromatization

Ostarine is definitely a lot weaker in comparison to steroids but it has only 1% of its side effects. This means that MK 2866 is a lot safer and will still have great results.

My Review

Ostarine and its benefits are backed by countless research and studies. But, before you go to purchase this compound, I want to share my experience and results using MK 2866.

When I was on this compound, I experienced some incredible benefits. Both the muscle I gained and the fat I lost were surprising.

Here is a quick summary of the SARM cycle I got on. I took these each day for 8-weeks.

  • Ostarine – 10mg per day
  • Cardarine (not a SARM) – 15mg per day

In the span of 8-weeks, I managed to gain 5lbs of muscle and lose 4lbs of fat. I also gained a lot of strength, my bench press went from 270lbs to 290lbs. Keep in mind, that I am not a beginner in lifting and if I did a cycle like this when I started lifting, my results would be a lot more impressive.

Although I used Cardarine in my cycle, most of the results I have experienced are due to Ostarine. I used Cardarine to help me increase my endurance.

Overall, I was very satisfied with my cycle and I would definitely do it again, especially because I didn’t experience any side effects.


Using steroids has some adverse effects on the body, and one of the most common is an increase in cholesterol levels. And while SARMs has similar benefits as steroids, it doesn’t have steroidal side effects in the body.

According to studies, MK 2866 doesn’t raise cholesterol levels as steroids would. Ostarine can even help decrease cholesterol.

Heart health

Based on the same study conducted by the Saint Agnes Hospital Department of Medicine, in addition to preventing and treating muscle wasting, MK 2866 also resulted in a decrease in both the HDL and LDL cholesterol levels.

Dosage And Cycle Length

We recommend that you start with a dosage of 15mg or 20mg per day. This seems to be the best dosage for getting the most optimal results with no side effects.

At this dosage, you won’t be suppressed at the end of the cycle or at least you most likely won’t feel the suppression and it will go away in a matter of weeks. Of course, this will only be true if you have real pure, high-quality MK 2866 available.

We recommend that you stay on your cycle for 8-weeks, this seems to be the same for almost all SARMs. Try to keep your cycle length to 8-weeks or 10-weeks maximum.

How To Take ostarine

Taking MK 2866 is very easy and simple, especially if you purchased it in the liquid form. Put your desired dosage into a glass that you fill with water and then you drink it.

You can go a step further than that, to assure that you get the most out of your dosage. You can do this by taking your Ostarine dosage sublingually.

This means that before you swallow your dosage, keep it under the tongue for a few seconds. Because of the tissue under the tongue, all of Ostarine will be absorbed into our blood flow.


Some beginners freak out when is the best time to take Ostarine, but it doesn’t matter that much. I take the compound in the morning.

When it comes to the half-life of Ostarine, research confirms that it’s 24 hours. This means that we should take our MK 2866 dosage once every 24 hours. This way, we will keep Ostarine levels in our body optimal and because of that, our results will be very good.

You can even take it one step further by splitting your dosage into two parts and taking the first in the morning and the second in the evening. Basically, take half a dosage every 12 hours.

Research suggests that this is even more effective than taking a dosage once every 24 hours. The difference isn’t that big though, so you don’t have to worry about missing out on results if you take MK 2866 once every 24 hours.

Ostarine PCT

I didn’t experience any side effects when taking Ostarine but some people claim that they get suppressed. This could be that they are very sensitive to this compound or that they most likely got a bunk product with something else other than MK 2866.

If you are suppressed after an Ostarine cycle, we recommend that you wait a few weeks because most likely your body will recover very fast.

Some people do PCT (Post Cycle Therapy) but the problem is that a PCT can have side effects. Sure, you will recover faster but in my opinion, it’s better to do it naturally and just wait out a few weeks.

However, the only way to be 100% certain if you need a PCT or not, is to get a blood test done at the end of your cycle.

Ostarine Before And After Results

We will go over three Ostarine results.

For more results like these check out our Ostarine before and after results with pics article.

Ostarine before and after

As we can see, his results are pretty good. He lost about 5% body fat and gained a few lbs of muscle. The before and after picture can look deceptive because he is tanned in the after picture. Results like this are easily achievable with hard training and keeping an eye on your diet while you are on your cycle.

His cycle:

Week Ostarine PCT
1-8 20mg a day /

Ostarine results

This are a lot better results than the first person. Still, there is an obvious lighting difference in the after picture, so that can be deceptive. He probably gained about 4lbs of muscle and lost 3-4% body fat. Keep in mind, the after photo is deceptive because he has a pump/is just finished with his workout and he has good lighting compared to the bad lighting in the before picture.

His cycle:

Week Ostarine PCT
1-8 20mg a day /

This is a very impressive transformation. He managed to lose quite a bit of body fat as well as put on a few lbs of muscle. All of that in just 49 days.

It’s obvious that he kept an eye on his diet and trained hard.

His cycle:

Week Ostarine PCT
1-7 20mg a day /

My Ostarine Results

I recently did an 8-week Ostarine cycle stacked with GW 50156. My goal was to lose body fat as well as gain some muscle mass. Even though I stacked Ostarine with Cardarine, I could have achieved the same results without it as well.

For me, the cycle was very successful, I was able to drop down from 16% body fat all the way down to 10% body fat. Not only that, but I also gained a few lbs of muscle on top of that thanks to Ostarine. Also, I didn’t lose any strength gains even though I was cutting, in fact, I actually gained a few lbs on all my major lifts.

I was eating at maintenance calories during the cycle. I was able to eat at maintenance calories and lose fat because of Cardarine. If I didn’t take Cardarine in this cycle, I could have achieved the same results, I would just have had to eat in a calorie deficit.

Obviously, eating at maintenance is easier to do, that’s why I like to stack MK 2866 with Cardarine when I want to cut body fat and gain a few lbs of muscle at the same time.

My cycle:

Week Cardarine Ostarine PCT
1-8 15mg a day 10mg a day /

I didn’t need to do a PCT (Post Cycle Therapy) because I wasn’t suppressed at all. As we said, MK 2866 is very mildly suppressive and doesn’t require a PCT, especially at dosages like this.

How To Get The Most Out Of Ostarine

Now that we’ve covered mostly everything about this compound and what you can expect from it, let’s go over some tips to get the best possible results on your Ostarine cycle.

Our four tips:

  • Train hard
  • Stay on a clean diet
  • Buy pure, high-quality Ostarine
  • Keep training after the cycle

The first two are obvious but still, a lot of people don’t realize how important they are. While MK 2866 is definitely a cheat code when it comes to getting results in the gym, it’s not a magic pill that will make you shredded and strong without any work or without at least a decent diet.

The truth is, you have to at least moderately workout and eat a decent diet to get great results from this compound. You’ll be glad you trained hard towards the end of your cycle when you start noticing obvious results.

What we mean with the third tip is to avoid bunk products. Some people buy underdosed, fake Ostarine and because of that, they get worse results than they could have gotten. Also, they might get unnecessary side effects, that Ostarine actually doesn’t cause but they experience them because of some other substances mixed into their bunk product. Make sure that you buy pure compounds.

The last point, training after the cycle is over, is also very important. If you train after the cycle, you will be able to keep all your gains. But if you completely stop training and start eating a very bad diet after your MK 2866 cycle, you will slowly lose your gains.

Where To Buy Ostarine

We have to buy our Ostarine and other SARMs from trusted vendors who sell real and pure compounds. This way we can avoid side effects that people experience when they receive fake, bunk or spiked compounds.

There are a lot of bunk products out there and because of this, I test SARMs from almost all available companies every few months and have them tested for purity at a local lab that offers analytical services.

I keep the top companies on the’s list of recommended companies.

Recommended, Verified Ostarine Sources

These are verified companies that have pure and reliable products. If you’re buying Ostarine or any other SARM or research chemical, you should buy it from one of the sources on the list.


In conclusion, Ostarine is a great compound for beginners and advanced SARMs researchers. It has great benefits like promoting lean muscle gain and fat loss as well as great strength gains.

I really like Ostarine because it’s the most researched and mild SARM on the market. There are a lot of studies backing it and it’s well on its way to one day, hopefully, get FDA approval to treat muscle wasting diseases.

Make sure to buy Ostarine from trusted vendors like my recommended companies so you won’t risk bunk products with unnecessary side effects.

Muscle mass gains
Fat loss as well as keeping muscle mass on a cut
Strength gains


Let’s go over some frequently asked questions about MK 2866 and answer them.

What Is Ostarine (MK 2866)?

Ostarine is one of the most popular and widely used SARMs. It has been clinically proven as a powerful muscle building compound that also helps in losing weight and increasing endurance with little side effects, unlike illegal steroids.

How Does Ostarine (MK 2866) Work?

Ostarine works similarly to steroids, although it is more selective than the latter. It selectively binds to the androgen receptors in your muscles and tissues and avoiding the receptors in your organs, which is why it has minimal side effects compared to steroids.

What Benefits Can You Get From Ostarine?

Ostarine has immediate and strong effects in binding with androgen receptors in the body, specifically targeting your bicep, tricep, chest, leg, and back muscles. Based on clinical studies, moderate Ostarine dosage of 10mg per day can rapidly boost your muscle mass, shred fat, and increase your overall strength.

What Is The Best Ostarine Stack?

Depending on your goals, you can personalize the Ostarine stack or cycle you are going to follow. If you want to lose weight, taking it with Cardarine or Stenabolic (SR9009) would be a good idea. If you want to bulk up we suggest that you use LGD 4033 or RAD 140.

What Is The Proper Ostarine Dosage?

The recommended dosage for Ostarine is between 10mg to 20mg, although it is best to start with a small dosage if you are a beginner to help assess your system’s tolerance to the compound.

What Is Ostarine’s Half-Life?

Ostarine has a half-life of 24 hours, which means 50% of MK2866 will be out of your system after one day. This is why we recommend that you take your dosage once every 24 hours. It will take around a week for Ostarine to be completely out of your system.

Can Ostarine Cause Cancer?

Absolutely not. Real Ostarine does not have any correlation with cancer.