Ostarine (MK-2866)

MK 2866 or Ostarine is a type of ‘Selective Androgen Receptor Modulator’ (SARM).  This experimental drug was developed in 2009, by the company Gtx in an effort to fight muscle wasting diseases. As with many other performance enhancing drugs, MK-2866 accidentally turned out to be a side effect free aid for bodybuilders. In a nutshell, MK-2866 is a fantastic SARM for building and preserving lean muscle mass. Let’s not forget about its healing properties on both muscle and bone tissues.

Time to have a further look at ostarine in more detail…

The benefits of using MK 2866

MK-2866 gives you the following benefits:

  • Increasing your lean muscle mass gains.
  • Boosting your lifting strength.
  • Increasing your lifting endurance.
  • Improving your joint healing abilities.

The benefits of MK-2866 compared to other SARMSs

  • It doesn’t have androgenic properties in the heart, prostate or colon tissue.
  • The metabolite MI which interferes with your vision is not found in MK-2866.

How does MK 2866 work?

Similar to many types of SARMs, MK-2866 binds to the androgen receptors but it does not convert DHT (dihydrotestosterone) into estrogen. Estrogen conversion is the main issue connected with taking steroids; as this can lead to many side effects e.g. man boobs, hair loss and an increase in body fat.

MK-2866 does increase protein synthesis and nitrogen retention, which are the main building blocks for muscle mass. Specifically, ostarine targets the bone and muscle receptors cells and this is why it has such a high anabolic impact within the body. This is good news for developing and protecting muscle tissues- this is why MK-2866 is such a popular SARM within bodybuilding circles!

It has been studied 8 times by GTx, the results indicated that MK-2866 produced increases in lean muscle mass and overall strength (1). These results are pretty impressive as the 8 studies had a sample population of around 600 people!

The effects of MK-2866

We have established that MK 2866 can be used for boosting muscle mass and for preserving your hard earned gains. This means that MK-2866 can be used for both the cutting and bulking stages of your training program. You can expect to achieve significant gains in muscle mass without water retention, aching joints and man boobs– these are often associated with steroid use. Therefore, your lean muscle gains are a whole lot cleaner and healthier when using MK 2866.

benefits of ostarine (mk-2866)

The Cutting Phase

This is probably the best time to use this type of SARM, due to its muscle protecting qualities. To burn body fat, a useful strategy is to expend more calories than you eat. Being in a calorie deficit can put your lean muscle mass at a potential risk. A top tip is to protect your muscle mass by combining a high protein diet with MK-2866, as this keeps your metabolism high. This scenario facilitates a constant fat burning especially when mixed in with HIIT (high intensity interval training).

On the flip side of the coin, if your metabolism is low or crashes this makes burning fat hard work. Always think about protecting your muscle mass and metabolism. This is especially the case during the cutting phase, as bodybuilder’s often reduce their calorie intake to achieve their physique goals. Suggested dosing of MK-2886 during the cutting phase is between 12-15 mg for 4-6 weeks.


MK-2866 is very competent at creating new muscle mass. Research has indicted that 1-2mgs of MK-2866 over a 12 week period increased lean muscle mass by 3 pounds (2). In addition, there was no change to the subject’s lifestyle in terms of diet and exercise. These results are quite impressive as the subject’s activity levels were relatively normal. Therefore, the catalyst for the increase in lean muscle mass was the MK-2866 (2). Suggested dosing of MK-2866 during the bulking phase is between 15mg-25 mg for 4-6 weeks

Treating injuries

MK-2866 can boost joint healing and repair, sometimes injuries can be caused by over training, poor training methods and recovery routine. If we protect the structure of the joints (proper form when lifting is massively important), as well strengthen the ligaments and tendons; we can continue to train harder for longer, whilst lowering the risk of injuries.

Interestingly, due to MK-2866’s ability to strengthen bone density it is often used to treat osteoporosis (particularly high in post-menopausal women and men over 50 years). Research has indicated that MK-2866 is better at preventing injuries than testosterone (3). The suggested dosage of MK-2866 for treating injuries is 12.5 mg a day.

Side effects of Ostarine

The current research indicates that there are no side effects associated with MK-2866. The main reason is because ostarine does not have an estrogenic nature. Thus, there are no reported health issues such as: water retention, bloating, gynecomastia, acne, hair loss, prostate issues, liver toxicity, cardiovascular or high blood pressure associated with MK-2866.

Anecdotally individuals did report a slight suppression of their testosterone levels, when consuming high dosages of MK-2866 for 8-12 weeks. However, their testosterone levels did return back within the normal range within 3-4 weeks after cessation.

Additional dosing information

You administer MK-2866 orally. For the main purpose of muscle preservation, it is recommended that you consume 15 mg per day. For muscle mass gains, it is recommended to consume higher amounts within the range of 20-25 mg. Usage should normally last for a cycle of 6-8 weeks and then have a break of 4 weeks– once the cycle has been completed.

Although there may be a slight reduction in testosterone levels, a post cycle therapy may not be needed. However, the 4 week break will give your body the chance to normalise, the testosterone levels should eventually return back to normal. MK-2866 does have a half-life of 24 hours and there is no advantage to taking multiple doses throughout the day. A good strategy is consume the right dose of MK-2866 in one go, preferably with a main meal.


When dieting, MK-2866 will help with strength maintenance and enhancing muscle mass. However, by adding another SARM into the equation will increase muscle mass and fat loss. Try using GW-501516 (Cardarine) and MK-2866 together when cutting, as it boosts cardiovascular endurance for longer periods of time. Contrary to current bodybuilding trends, cardio still has a part to play in the cutting phase. The recommended daily doses are 25mg of MK-2866 and 20mg of GW-501516 during the cutting phase.


MK 2866 can boost your lean muscle mass, lifting strength, lifting endurance and it can be used for its healing properties. Ostarine has no recorded side effects and can be used in both the cutting and bulking phase of your training program. Take between 20-25mg for the best results, and it can be stacked with other SARMs (GW-501516) to boost your muscle mass and total fat loss.

ostarine for sale


[1] Zilbermint MF et al. Future Oncol. 2009 Oct; 5(8):1211-20.

[2] Madeddu C et al. Curr Opin Support Palliat Care. 2009 Dec; 3(4):258-62.

[3] Narayanan R et al. Nucl Recept Signal. 2008;6: e010. 

[4] Jack Steel. MK-2866 Ostarine Exposed; 2015

One Response to “Ostarine (MK-2866)”
  1. peter t mullen July 20, 2018

Leave a Reply