Ostarine (MK-2866) Review – Dosage, Side Effects, and More

By: Rob Miller
MD Reviewed By: Helen Okoye, MD What's This?
Fact Checked On: 6-2-2024

Home » SARMS » Ostarine (MK-2866) Review – Dosage, Side Effects, and More


How Ostarine Works
Potential Side Effects of Ostarine
What the Research Says about Ostarine
Highlighted Benefits of Ostarine
Best Way to Use Ostarine
Stacking Method
Where Should I Buy It?

1. Ostarine: The Perfect S.A.R.M.

When it comes to the poster boy for S.A.R.M.s, it’s hard to think of a better choice than Ostarine.

chemyo ostarine
Ostarine sold by Chemyo.

Also referred to as MK-2866, Ostarine has been a hot topic in the medical field as well as the bodybuilding industry.

Due to its ability to promote the growth of healthy muscle tissue and bone in those with muscle deteriorating conditions, Ostarine has been the subject in several ground-breaking studies like this one, this one, and this one.

2. How Ostarine Works and Benefits

Just like other S.A.R.M.s, Ostarine works by targeting selective androgen receptors in the body.

https://www.supplementcritique.com/wp content/uploads/2017/02/ostarine chemical
^Ostarine chemical makeup

Once ingested, the compound attaches itself to these selected androgen receptors. From here, this is when the compound works its magic, promoting the growth of lean muscle tissue and promoting proper bone development. (Source)

Some users have even reported shedding body fat with Ostarine (more on that later).

3. Potential Side Effects of Ostarine

As I mention above, Ostarine, as a SARM, is going to maximize the anabolic benefits while reducing androgenic side effects. Unfortunately, there’s just no way to eliminate side effects completely with a SARM like Ostarine.

However, the intensity of the side effects is heavily dose dependent. While user reports may vary wildly, here are some of the potential side effects for men and women when using Ostarine:

  • Potential mild testosterone suppression

For example, one user on the Steroidology forum suggested that he’s seen blood tests that have proven total testosterone drops from Ostarine alone.

does ostarine cause testosterone suppression

Of course this is anecdotal, and should only be taken with a grain of salt.

  • Mild acne

For example, this guy had been taking Ostarine for 8 weeks when he started identifying spots on the side of his arms, upper chest, and back.

does ostarine cause acne

Again, anecdotal and no way to confirm that this happens to a wide swath of guys.

  • Mild (if any at all) hair loss

While reports are relatively rare, Ostarine has been reported in some to cause minimal hair loss.

hair loss reported from taking ostarine

With that said, this particular individual actually had a history of hair loss since the age of 19.

Hardly a correlation = causation scenario.

https://www.supplementcritique.com/wp content/uploads/2017/02/correlation does not imply

With that out of the way, in theory Ostarine should NOT cause hair loss.

This is because, by definition, a SARM like Ostarine is selective in which androgen receptors it stimulates by tissue.

There are androgen receptors in ALL tissue, including:

  • Brain
  • The skin
  • The scalp
  • Muscle

The only androgen receptors that Ostarine simulates is:

  • Bone
  • Muscle
  • Tendons
  • Ligaments

It does NOT stimulate the androgen receptors in the scalp, so in theory it should have NO effect on hair loss whatsoever.

4. How to avoid side effects altogether (or at least minimize the chances)

Assuming worst case scenario, the best way to combat the minimal side effects that you may have is to supplement with a PCT (Post Cycle Therapy).

clomid as a pct
^ Clomid – A common PCT

The most common ones are:

However, these 2 are really overkill in my opinion, especially if you’re only running a 4 week cycle.

You wouldn’t need a hardcore stacked PCT, a simple, mild PCT will do the trick.

These include:

5. Ostarine Cycle Logs

I haven’t had a chance to personally test out Ostarine yet, but I’ve read through COUNTLESS logs on a wide variety of sites and it looks legit.

Here’s an example of a typical 4 week cycle I found on a site called Evolutionary.org:

Day 1

day 1 ostarine cycle

Day 2

day 2 ostarine cycle

Day 3

day 3 ostarine cycle

Day 5

day 5 ostarine cycle

Day 7

day 7 ostarine cycle

Day 16

day 16 ostarine cycle

Day 18

day 18 ostarine cycle

Day 19

day 19 ostarine cycle

Day 21

day 21 ostarine cycle

Day 25

day 25 ostarine cycle

Day 27

day 27 ostarine cycle

Day 30

day 30 ostarine cycle

6. What the Research Says about Ostarine

So what exactly has science demonstrated about Ostarine?

Well, it’s important to note that no professional medical organization is going to fund a study that has the sole intention of proving Ostarine as a highly effective muscle mass enhancer for the purpose of bodybuilding.

Especially when S.A.R.M.s have been banned by the WADA.

ostarine is banned by WADA
^ WADA banned substances list

With that said, you can take a look at the medical research, its medical applications and apply those same benefits to what you can expect when you use a SARM.

In the past, anabolic steroids had been the go-to solution for many conditions that featured muscle and bone deterioration.

anabolics for muscle wasting

With the first study of a SARM showing so much potential, studies have focused on replacing anabolic steroids with SARMS like Ostarine.

In fact, the first study was performed back in 1998 and it involved guess which SARM.

ostarine clinical study

That’s right, Ostarine.

In one of the most famous studies, the use of Ostarine resulted in amazing gains. Subjects were not prescribed a specific diet or training program and yet, all subjects experienced a dose dependent gain of lean muscle tissue. Subjects took 3 mg per day of Ostarine and ended up gaining an average of 1.3 kg or nearly 3 pounds of muscle mass.

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They gained almost 3 pounds of muscle and did NOT add in supplemental training or a new way of eating! You don’t need me to say it but imagine what kind of results you can achieve if you were to add in a hypertrophy focused training program and meal plan. (1-3)

Related Article: 5 BEST SARMS For Bulking

7. Benefits of Ostarine

Here’s a quick rundown of the finer points of Ostarine:

  • Promotes anabolic properties
  • Androgenic side effects (if any) are minimal
  • Will not negatively impact the liver
  • Supports lean muscle tissue growth
  • Protects current levels of muscle and bone
  • Will not convert to estrogen or dihydrotestosterone
  • May promote higher levels of strength, power, and performance

8. Best Way to Use Ostarine

There are two ways to administer Ostarine:

  1. An oral supplement usually in tincture form
  2. An injectable dose.


  • How to choose the right dose:  Dosage will vary based on what your goals are. Also, remember that gains AND side effects are dose dependent. You may see more muscle mass with a higher dose but you’ll also see a greater risk of testosterone suppression. Any cycle that runs four or more weeks should be followed with a PCT, as mentioned above.
  • Lowest possible dose: 3 mg
  • Average dose (according to user reviews and brand recommendations): 12 to 15 mg
  • Highest dose (ideal for intense bulking): 25 mg (A PCT is absolutely required at this dose)

Cycle Length

  • This will vary by company. The general time frame is 4 to 6 weeks.

Cycle Support

  • Cycle support may be needed depending on the dosage. Again, the lower the dose, the less chance you’ll need a PCT.

9. Stacking Method

While you can stack Ostarine with different anabolic compounds, I’d argue against it. Ostarine has a specific function that involves targeting exact androgen receptors in order to maximize your results while minimizing your side effects.

What do you think will happen if you throw a wildcard like a prohormone on top of that?

Remember above how I mentioned that prohormones serve up some anabolic features but also come with the androgenic side effects?

Why ruin a good thing?

The only thing you may want to consider stacking Ostarine with is a quality intra-cycle support supplement if you are using it at a higher dose.

Something like Primeval Labs Mega Cycle support would be a good choice, here’s their site:  https://www.a1supplements.com/primeval-labs-mega-cycle-support

10. Where Should I Buy It?

I’ve used close to half a dozen brands of Ostarine over the years, and I personally recommend the Ostarine over at Chemyo.

chemyo brand ostarine
Chemyo brand Ostarine.

It’s made of great quality, it’s 3rd party tested, and it works…period.

Here’s a link to their Ostarine page (use coupon code redeem10 to save 10%): https://www.chemyo.com/mk2866/?ref=125

Or if you prefer to learn more about Chemyo first, click here to read my full review.

11. Conclusion

When muscle mass and strength boosting is your fitness goal, it can be easy to reach a plateau where you just aren’t seeing the results you once were. Once you cycle through various diets and training methodologies, you may still want something more to help push your body past it genetic limitations.

Prohormones are tempting but the lack of results and the amount of side effects that you get will squash that temptation. Anabolic steroids are incredibly effective but also highly illegal and come with long term health complications. Then there’s a Selective Androgen Receptor Modulator.

While banned by the WADA, finding a quality S.A.R.M. is still very easy and the compound is highly effective.

One of the best S.A.R.M.s on the market is Ostarine. Backed by scientific research and studies, Ostarine has been shown to significantly increase lean muscle tissue and strength.

User reports claim that it promotes a higher level of fat burning. If you want a new way to smash your limitations, Ostarine may be what you are after.

From all appearances, it has a good track record for delivering on the many promises that Ostarine claims. Of course, as with anything, you will find good and bad reviews however.

Of course, you should always do your homework and make sure that it is in line with your own best overall health, and hopefully you get to enjoy the benefits that it has the potential to offer.

Have you used Ostarine? Leave your review below!


  1. Ramesh Narayanan, Michael L. Mohler, Casey E. Bohl, Duane D. Miller, and James T. Dalton. Selective androgen receptor modulators in preclinical and clinical development. Nucl Recept Signal. 2008; 6: e010.
  1. Dalton JT, Barnette KG, Bohl CE, Hancock ML, Rodriguez D, Dodson ST, Morton RA, Steiner MS. The selective androgen receptor modulator GTx-024 (enobosarm) improves lean body mass and physical function in healthy elderly men and postmenopausal women: results of a double-blind, placebo-controlled phase II trial. J Cachexia Sarcopenia Muscle. 2011 Sep;2(3):153-161. Epub 2011 Aug 2.

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User Questions and Answers

Hi I’ve been researching Ostarine recently. I see it’s banned by WADA. My question is if someone were to order this product to said persons home although they have no affiliation with any lab or lab experience would the be considered illegal and grounds for jail time? -Brent

Being banned by the World Anti-Doping Agency doesn't make something illegal. It just means competing athletes covered under the regulatory body can't use them. Ostarine is legal in the US.- Rob

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9 out of 9 people found this question helpful.

MK-2866 purchased in pill form 90 capsules how many should be used per day over a 4 week cycle? -Alvin

Your daily dose can be anything from 3 mg to 25 mg, depending on what your goals are. The average dose is 12-15 mg per day. Remember that both gains and side effects are correlated with the dose you take.- Rob

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8 out of 9 people found this question helpful.

Is it safe to use osterine with another sarm like mk 677, gh enhancer? Will it increase the chance of androgenic side effects like hair loss? Or anything else? Thank you -Frank

Yeah there shouldn't be any issues with that.  Yeah there's a lot of misconceptions when it comes to Ostarine and hair loss. I've seen some anecdotal reports of guys reporting hair loss, but in my opinion it's HIGHLY unlikely that the Ostarine cause it. SARMs like Ostarine only stimulate bone, muscle, tendon and ligament androgen receptors. It does NOT stimulate the androgen receptors of the scalp, so it shouldn't have any effect on hair loss (or even hair growth for that matter).- Rob

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8 out of 11 people found this question helpful.

Author: Rob Miller

Supplement Critique

Rob Miller founded SupplementCritique.com over 7 years ago, and has been the chief editor ever since. He has a diploma in Advanced Dietary Supplements Advisor, and worked at GNC for 3 years. He KNOWS supplements, both inside and out. Rob currently resides in Jupiter, FL, with his wife of 4 years.  Learn more about him in his Bio here. Follow him on Twitter , Facebook, LinkedIn, or find him on Google +.

Medical Reviewer: Helen Okoye, MD

Dr Okoye

Dr. Helen Okoye is an American Public Health Physician, Health Care Executive, Researcher, Entrepreneur with a Doctor of Medicine Degree (MD), an MBA in Healthcare Management, and a Masters in Epidemiology/Public Health). Her specific responsibilities for Supplement Critique including reviewing previously published articles for accuracy and relevancy. Her expert opinion was featured on NBC News for the President’s physical exam. Learn more about Dr. Okoye here. Follow here on Twitter and Instagram.

11 comments on “Ostarine (MK-2866) Review – Dosage, Side Effects, and More”

Leave A New Comment

  1. Two questions – Q1: Did you find anywhere in your research about Ostarine raising blood pressure? Q2: I have read that real Ostarine is only available as a tincture and that pills are fake and most likely pro-hormones…thoughts?

    1. Hey Chris,
      As far as Ostarine and Blood pressure, yeah I have heard that it can possibly raise it. I never experienced it, but from what I understand it’s possible (although not prevalent). And yeah you definitely want to avoid pills, the vast majority of them are severely under-dosed and ineffective. Check out Chemyo Ostarine. I’ve used a handful of brands and it was by FAR the best, here’s their site – https://www.chemyo.com/mk2866/?ref=125
    1. Hey Bill,
      Unfortunately the only way I’ve ever seen it sold was in liquid form. I’m sure there are a few of them out there, I just haven’t come across any.

  2. Given the half life – how long would it take to get Ostarine out of your system once a full cycle is finished?
    1. Hey Steven,

      It’s really not possible to cite a blanket amount of time, but if you’re being drug tested, the recommendation is to discontinue Ostarine and flush your system for 30 days.
    1. Hey Tony,
      I wouldn’t take more than 2 a day and that’s if you’re looking to gain a lot. And make sure you do PCT after your cycle.

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