MK-2866 (Ostarine)

(17 customer reviews)


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Ostarine, or MK-2866, is a versatile SARM with a strong anabolic effect. It was created by GTx to treat muscle wasting disorders such as cachexia. Today, Ostarine is commonly used by athletes for both bulking and cutting.


Benefits of Ostarine

Low Side Effect Profile

A lot of people have found themselves using SARMs because they were turned off by the idea of dealing with the consequences of anabolic steroid use. Some of those can include gynecomastia (gyno), hair loss, and in extreme cases, enlargement of the heart.

Luckily, ostarine is extremely mild and well tolerated by those who use it. It is very uncommon to experience side effects while on cycle. Out of all of the SARMs you can use, Ostarine has the least likelihood of causing any unwanted side effects.

Scientifically, multiple studies demonstrate its high safety profile and efficacy, making it the perfect choice for those who are concerned with potential side effects from SARMs.


MK-2866 can be used to bulk, cut, and even re-comp (lose fat while gaining muscle). It’s a staple in many sarms cycles for this very reason.

You can also stack it with other compounds to improve your overall results.

Is Ostarine Safe for Women?

Ostarine is safe for women since it does not carry heavy androgenic properties. To be safe, women should use a lower dosage (10mg a day) and work their way up to a maximum dose of 20mg per day.

More and more women are ditching steroids like Anavar in favour for SARMs. There is no need to risk the androgenic side effects of steroids (clitoris enlargement, deepening voice) when SARMs are so readily available.

If you’re a female and are interested in using SARMs. Ostarine has been a preffered choice before trying other extreme options.

Improved Physique

The physique changes you can achieve from running an eight-week cycle of MK-2866 are nothing short of mind blowing.

Expect dry, vascular gains while on cycle. Even with no change in diet, Ostarine can radically improve your overall athletic condition. That being said, you should be eating as clean as possible in order to maximize your results. You know the drill, keep the protein high and stay away from processed carbs.

This study is a great example of the anabolic effect Ostarine has on the body:

Ostarine treatment resulted in a dose dependent increase in total LBM, with an increase of 1.4 kg compared to placebo (p<0.001) at the 3 mg dose. Increased LBM translated to an improvement in the stair climb test in both speed (+15.5% ± 12.9 faster time, p=0.006) and power (+25.5% ± 20.3 watts, p=0.005). There were no serious adverse events reported.

DOI: 10.1200/jco.2007.25.18_suppl.9119 Journal of Clinical Oncology 25, no. 18_suppl (June 20, 2007) 9119-9119.

What Results to Expect

Muscle Growth

It’s not a secret that SARMs can help you build large amounts of muscle. Ostarine is no different. During an 8 week cycle of Ostarine, you can expect to gain around 7-10lbs of lean body mass.

This study shows that in addition to gaining a considerable amount of muscle mass, test subjects saw a nearly 30% reduction in insulin resistance. If you follow any of the research regarding intermittent fasting (sometimes called Lean Gains), you know that insulin sensitivity is a crucial part of how effectively your body can utilize carbs. According to the study:

…subjects treated with 3 mg/d of Ostarine had on average an 11% decline in fasting blood glucose, a 17% reduction in insulin levels, and a 27% reduction in insulin resistance (homeostasis model assessment) as compared to baseline…

Narayanan R, Mohler ML, Bohl CE, Miller DD, Dalton JT. Selective androgen receptor modulators in preclinical and clinical development. Nucl Recept Signal. 2008;6:e010. doi:10.1621/nrs.06010

Bottom line? Ostarine stimulates muscle growth by targeting anabolic pathways and by reprogramming your body to more efficiently utilize carbs.

Fat Loss

Although not a direct aide to thermogenesis, Ostarine can help promote fat oxidation in humans:

Secondary endpoints included safety of GTx-024, effects on fat mass, bone mineral density, blood glucose, and insulin. This study is the first to demonstrate the ability of a nonsteroidal, orally bioavailable SARM to increase lean muscle mass and improve physical function.

Dalton JT, Barnette KG, Bohl CE, et al. 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;2(3):153-161. doi:10.1007/s13539-011-0034-6

Users who are in a caloric deficit will experience much better muscle retention compared to natural lifters. Don’t be afraid to push the envelope when it comes to cutting calories. If you’re on cycle, you can easily maintain your current muscle mass in a 1000 calorie deficit.

In addition, it has been proven that increasing muscle mass will increase TDEE (how many calories you need per day). When you gain muscle, your body will naturally burn more fat as energy in order to keep that muscle.

Strength Gains

Ostarine especially shines when combined with strength training, and users consistently report strength gains similar to those found in anabolic steroids.

In fact, it is not uncommon to add 30lbs or more to your one rep max for bench press or squats. Strength gains are one of the first things people tend to notice when they’re taking Ostarine.

Having a stronger body will inevitably improve your athletic performance regardless of what sport you play (if any). I’ve talked to football players, sprinters, rowers, even basketball players. All of them reported positive increases in their performance during and after their cycles.

Side Effects

One of the main concerns people tend to have when adding any sort of performance enhancing drug is what type of side effects to expect.

SARMs, for the most part produce very little side effects when used in responsible doses. Ostarine has the lowest risk of side effects out of any SARM used by most, so it’s a great option if that is one of your concerns.

With that being said, there will always be some rare occasions of people experiencing side effects which we have mentioned here below:

Depression / Anxiety

This has only been seen happen in one case, and it may not be due to using SARMs. This user reported feeling depressed around a week after starting Ostarine.

Hair Loss

Hair loss from SARMs ONLY occurs in people who already have male pattern baldness. If your hairline is fine, this does not apply to you.

This user on the AnabolicMinds forum reported hair shedding on Ostarine, but also mentioned in a later post that it reversed after stopping use.

However, Ostarine is not androgenic in nature. It is very possible that this user received a fake product (that contained something else) and that is what caused the shedding.


Some people with naturally low testosterone might experience some lethargy while on cycle. This is because SARMs slightly suppress your body’s natural production of testosterone.

The good news is that your body will naturally fix the imbalance within a month after you stop taking it. Studies show it takes around 5 weeks to completely recover.

Note: The above study was completed using LGD-4033.

If you have been diagnosed with low T, you might want to consider getting on TRT prior to starting a cycle.

Dosage Guide

The recommended dosage for Ostarine is between 10mg and 20mg per day. Follow these guidelines when deciding how much to use in your next cycle:

  1. Start low and work your way up (known in the field as titrating)
  2. Increase your dosage every few days, not all at once
  3. Cutting cycles generally require a smaller dose than bulking

With those key points in mind, let’s jump into a few sample dosage guides.

Dosage for Bulking

Bulking on Ostarine will require a slightly higher dosage than cutting, for the reasons outlined above. It takes a higher dose to create muscle than it does to retain it.

For those reasons, research indicates that 20mg a day for anyone weighing over 185lbs. For those weighing less, you should give 10mg a day a try and see how you react beforehand.

If you plan on doing a 20mg a day dose, it is suggested to work it up like this:

  • 10mg for week 1
  • 20mg for week 2 and beyond

For bulking cycles, it is advised not doing a cycle which lasts longer than 12 weeks.

Dosage for Cutting

Using MK-2866 for a cutting cycle will require a smaller dosage than you would need for bulking. Retaining muscle mass while in a deficit doesn’t require nearly as high of a dose as creating new muscle mass does. You’re also less likely to experience side effects with smaller doses.

No more than 20mg a day while on a cutting cycle is recommended.

Start at 10mg a day for your first week and increase to 20mg for week two and beyond.

Cutting cycles should not last any longer than 12 weeks in order to prevent suppression.

Half Life

The half-life of Ostarine is 24 hours. This means that you can dose once per day with no issues in peak blood plasma levels.

Some people also enjoy dosing pre-workout, however studies haven’t shown any noticeable difference in effectiveness when taken before a workout.

Where to Buy

If you want to buy Ostarine online, there are a few things you should know before you place an order.

First of all, that there are many fakes out there. It has been reported that roughly 75% of Ostarine on the market provided are either fake or under dosed products.

One of the most common reasons for this is that SARMs are expensive to manufacture, and shady vendors take advantage of consumers who assume that the products they are purchasing are legitimate.

MedLabsAU is one of Australia’s longest running and trusted sources to purchase 99% high quality SARMs from and has many verified customer reviews which you can view here.

Use During PCT

One of the more interesting ways to use this compound is to take it during your post cycle therapy. Since Ostarine is so mild, it can in theory be used to retain muscle mass while coming off of other anabolics such as testosterone.

If you plan on doing this, you must know two things:

  • The benefits of using SARMs during PCT are hypothetical at best.
  • Only use low doses, no more than 10mg per day.

Depending on who you listen to, you will find mixed reviews on using it for this purpose. It is not advised using it during PCT unless you are coming off of a heavy cycle (tren, deca, etc).


When does Ostarine kick in?

It should start working within one week. You will continue to feel it get stronger and stronger over the course of a month or so. By 30 days into your cycle, you will be in full beast mode.

How suppressive is Ostarine?

It is actually one of the least suppressive SARMs in existence. Blood work consistently shows that any reduced levels of testosterone are reversed within a month or two. This is one of the reasons it’s so popular.

How long does Ostarine stay in your system?

If you are drug tested it is highly recommended that you stay away from all SARMs. If you plan on taking it anyways, allow a solid 1-2 months to let it clear your system completely.

Do I need to do PCT after?

Usually not, depending on cycle length. If you plan on going the full 12 weeks, it might be a good idea to do 4 weeks of tamoxifen (Nolvadex) at 20mg for four weeks. You will not need anything stronger than that (stay away from Clomid).

What can I stack with it?

A good option is always MK-677 to raise your HGH levels. You can also stack it with Cardarine for an even more potent drying effect.

Final Thoughts

In conclusion, anyone who is looking at starting their first SARMs cycle. It has a low side effect profile, is well tolerated by most users, and can be utilized for bulking, cutting and re composition.

Additional information

Weight 0.05 kg

17 reviews for MK-2866 (Ostarine)

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Showing 15 of 17 reviews (5 star). See all 17 reviews
  1. Chris

    Does what it says on the tub – decent gains in strength and muscle mass over an 8 week cycle, with no side effects. No PCT needed and only minor loss of gains post cycle.

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  2. Angus

    So far so good, about to order a second batch, pretty happy so far!

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  3. Gabriele Costa

    Great product that has little side effects and great results

    1 out of 1 people found this helpful. Was this review helpful to you?
  4. Shannon Antich

    good strength and muscle gains,

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  5. Ben Walters

    Did excatly what it said. Felt great using it, and kept all the progress.

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  6. Christopher

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    Seems good so far.

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  7. Clint

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    Happy with the purchase.

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  8. Anonymous

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    Amazing results, assisting in the weight loss and maintaining muscle, with some strength gains. Love it!

    1 out of 1 people found this helpful. Was this review helpful to you?
  9. Colin S.

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    It’s working well already.

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  10. Robert Cat

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    Fast delivery

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  11. Yehyah H.

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    Good product for good value … very well recommended

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  12. Ric Piz

    Fast delivery and excellent customer service received!

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  13. Clint

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    Yet to use this product although have been using the MK-677 and LGD-4033. Unbelievable results so far! Can’t wait to test this one out!

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  14. Mark

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    I actually had this 2 years ago and its consistent in smell texture and taste as the other batch. Will get bloods done in a month to confirm.

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  15. Anonymous

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    Quality product, very happy with purchase

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