What Is Mk 2866?

MK 2866 is a popular selective androgen modulator receptor. These are known as SARMs and are among the most widely used muscle growth enhancers. MK-2866 is also known as Ostarine and Enobosarm. 

SARMs have a remarkable ability to grow a person’s muscle mass. They attach to what is known as androgen receptors. Androgen receptors are cell receptors that bind to hormones like testosterone and dihydrotestosterone. 

When hormones attach to these receptors, this body responds to it with anabolic processes that create muscle growth, which lets the body bulk it quickly. SARMs like MK 2866 also affect how much IGF-1 the body produces, which is a significant growth hormone.

The substance is illegal to sell as a supplement. However, MK 2866 is commonly sold legally as a research chemical. It is also the interest of various medical studies for its potential use in assisting patients with the following ailments:

  • Cancer 
  • Cachexia 
  • Sarcopenia
  • Osteoporosis
  • Muscle wasting

Ostarine MK-2866 Liquid Vial SARM

MK 2866 is significant because it allows patients with low muscle mass to grow some back quickly with less effort. This increase in muscle would let patients move around and operate more comfortably. Some suggest that the substance be legal as treatment.


Ostarine is one of the most popular SARMs and muscle growth agents in general. Here are some of the potential benefits of MK 2866 on the body.

  • Rapidly builds lean muscle
  • Strengthens skeletal tissue
  • Improves physical appearance
  • It is not an anabolic steroid

It Rapidly Builds Lean Muscle

MK 2866 allows the body to build weight faster than it naturally would, especially during bulking season. Many users take the substance accompanying weight gain exercises and eating. Instead of building on the new weight as fat, SARMs allow it to grow as skeletal muscle tissue.

A 2007 study found that patients given random samples of 0.1, 0.3, 1, and milligrams of Ostarine for three months showed noticeable lean muscle growth compared to patients given a placebo. 

Patients receiving the 3-milligram dosage demonstrated a 1.4 kg increase in muscle compared with the placebo group. The study had also shown that the elderly patients saw improvements in their physical performance when tasked with climbing stairs. 

MK-2866 Strengthens Skeletal Tissue

Scientists have proven that MK-2866 builds and strengthens skeletal muscle. Skeletal muscle is the muscle connected to tendons, bones, and joints. This information is not completely surprising, as GTx Inc initially used the substance to treat osteoporosis. 

Because skeletal tissue controls the movements of joints, having stronger skeletal-tissue means you can move quicker and exert more force with your twitch muscles. MK 2866 has a positive effect on bone strength as well. 

Ostarine has shown an ability to increase bone mineral density and bone-volume density. In addition to this effect, Ostarine is notable for its positive effect on muscle vascularization.

It Can Improve Your Appearance

MK2866, SARM results

It is no secret that MK-2866 can leave users chiseled and defined when they pair the substance with physical activity and dieting. The SARM is especially useful here because it allows the body to retain more muscle after exercising, meaning you lose muscle mass slower than usual.

MK-2866 affects most skeletal muscle groups, so you do not have to worry about some muscles seeming disproportionately larger than others. The substance also burns fat, which makes users skinnier and lighter. 

It Is Not An Anabolic Steroid 

The substance is not an anabolic steroid, despite common misconceptions. Steroids are analogs of the hormone testosterone, while SARMs are synthetic ligands. Because MK-2866 is not an anabolic steroid, it does not suffer some of the same side effects steroids have. 

At first, anabolic steroids increase the levels of testosterone in the blood. However, this testosterone is aromatized and turns into excess estrogen. Elevated estrogen levels can cause changes in a person’s mood and the development of physically-feminine characteristics.

SARMs do not increase the level of estrogen in the body. Users do not have to worry about losing body hair or sex drive. This ability to induce muscle growth without increasing testosterone is because these ligands stimulate the receptors directly. 


Some aspects of MK-2866 might be concerning for certain people. They might feel there is limited information on SARMs because they are a relatively newer phenomenon. 

The substance has a lot of benefits and is one of the safer SARMs, but certainly has potential side effects. Here are some of the things you will want to watch out for.

  • SARMs have associated health risks.
  • There are stronger SARMs
  • Not FDA-approved

SARMs Have Associated Health Risks

Unfortunately, researchers have discovered that many SARMs have associated severe side effects in extreme cases. Donald D. Ashley, J.D, of the FDA, stated in 2017 that SARMs might increase the risk of heart attacks, strokes, and liver disease.

MK 2866 has shown the potential to cause liver damage. In 2021, a case report on Ostarine showed that a SARM inflicted liver injury on a patient for the first time in a biopsy. This report accompanies others of jaundice among users of this particular substance.

Professionals determine liver injury by using something called the R-factor. In the study, the patient’s R-factor was 0.8. Note that liver damage resulting from Ostarine is very uncommon. However, it is becoming more common due to the drug’s increasing popularity. 

Summer Swole - Aleks Salkin - The Hebrew Hammer

Nonsevere side-effects may include:

  • Acne
  • Nausea 
  • Voice changes

More severe side-effects can include: 

  • Liver toxicity
  • Acute myocarditis
  • Heart attacks
  • Strokes 

There Are Stronger SARMs 

Various other SARMs perform better than Ostarine in building skeletal muscle. In fact, the strongest SARM in existence is OTR-AC, which scientists developed by esterifying Ostarine. 

Despite its many benefits, certain supplement users claim it is better as a beginner supplement. SARMs like RAD140 are considered advanced and have higher chances of side effects. RAD140 has an anabolic ratio of 90:1 compared to MK 2866’s 10:1. 

rad 140 testolone vial

MK 2866 Is Not FDA Approved

The Food and Drug Administration does not approve MK 286. It is illegal to sell. Getting MK-2866 requires customers to purchase the substance as a non-supplement research chemical. 

Fortunately for many, it is not illegal to use the substance personally as a diet supplement, only to market it. This legal area means SARMs are not illegal to consume, only to sell.  

Because the FDA does not approve it, specific SARMs can be more obscure to obtain. The United States military does not allow its enlisted members to use MK-2866 or any other SARM. Likewise, sports teams do not allow their athletes to use the substance.

How Do People Use MK 2866?

People usually take MK 2866 orally. Depending on your fitness goals, you may want to adjust your dosage and diet accordingly. Foods that go well with MK 2866 are high in protein, like fish, meats, poultry, and super greens. 


Getting the appropriate dosage of MK 2866 depends on your size, weight, age, gender, and metabolism. According to WebMD, the average dose per day is 3 milligrams. 

Most bodybuilders and recreational users, however, report different dosages. Generally, adult males take anywhere from 5 to 25 milligrams a day. Women should take less, from around 5 milligrams to 10 milligrams daily.

Professional male athletes and bodybuilders often use more than 25 milligrams, some even starting their dosages at 50 milligrams daily. Note that women can experience side effects at higher doses. 

MK 2866 has a half-life of about 24 hours, meaning it will remain in your system a full day after taking it. It usually takes about two weeks for patients to notice the results in their muscle growth.

Can You Overdose With MK 2866?Fitness Shoot with The B.U.F.F. Dudes (plus Behind the Scenes) — Eddy  Fernandez Photography

Users can experience liver damage if they take MK 2866 orally at extreme doses. The science of MK 2866 toxicity is not well-known though it has a proven link to strokes and heart attacks in considerably rare instances.

Is MK 2866 Doping?

The World Anti-Doping Agency (WADA) bans MK 2866 and all selective androgen modulator receptors in sports. Despite being illegal in the Olympics, NBA, NFL, and MLB, SARMs, it is common for athletes to use it.


Many consider using growth supplements like anabolic steroids and SARMs to give cheating athletes an unfair advantage. Cheating athletes will almost always outperform their peers. 


That being said, most people who use MK 2866 are not professional athletes or bodybuilders, for that matter. Most use occurs among people using it as a simple diet supplement. 

MK 2866 Alternatives

There are numerous alternatives to MK 2866, both SARMs and other forms of muscle enhancers. It is not uncommon to stack MK 2866 with other SARMs to combine the effects. Some include:


  • LGD-4033 – Ligandrol is a stronger SARM than Ostarine.
  • Andarine – This SARM is better for women.
  • OTR-ac – The strongest SARM available.


Non-SARM alternatives to MK 2866 include muscle growth peptides, high protein diets, and HGH supplements. 

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