Ostarine MK-2866

Ostarine (MK-2866) description

Ostarine (also marked as MK-2866, Enobosarm and GTx-024) is a oral, nonsteroidal and Selective androgen receptor modulator (SARM), that was developed for treatment of conditions such as muscle wasting and osteoporosis (a health condition that weakens bones). In a phase 2a study, Ostarine was shown to increase lean body mass, decrease fat mass, and to modestly improve the homeostatic model assessment (HOMA), a measure of insulin sensitivity. It is the most and best clinically tested SARM to date. Ostarine has chemical formula C₁₉H₁₄F₃N₃O₃, molecular mass 389.33 g.mol⁻¹ and prolonged elimination half-life 24 hours.

Ostarine history and development

Ostarine was developed by GTx, Inc. for the treatment of conditions such as muscle wasting and osteoporosis. The company has invested approximately $ 35 million in its development.

In August 2011, there was a double-blind, placebo controlled phase II trial that focused on elderly men and postmenopausal women. In this study Ostarine showed statistically significant improvements in total lean body mass and physical function without androgenic negative side effects (which usually occur with steroid therapy).

In August 2013, GTx announced that Ostarine had failed in two Phase III clinical trials to treat wasting in people with lung cancer. They also said that is planned to pursue approval of Ostarine in Europe.

In 2016, GTx began Phase II trials, to see if Ostarine might be effective to treat stress urinary incontinence in women, but these studies failed in 2018 to achieve their primary endpoint in the ASTRID test.

Ostarine helps to achieve significant muscle gains

In 2006, a 12-week double-blind, placebo-controlled phase II clinical trial was conducted to evaluate Ostarine in 120 healthy elderly men (>60 years of age) and postmenopausal women. The primary endpoint was total lean body mass assessed by dual energy X-ray absorptiometry, and secondary endpoints included physical function, body weight, insulin resistance, and safety. Ostarine treatment resulted in dose-dependent increases in total lean body mass that were statistically significant (P < 0.001, 3 mg vs. placebo) and clinically meaningful. There were also significant improvements in physical function (P = 0.013, 3 mg vs. placebo) and insulin resistance (P = 0.013, 3 mg vs. placebo). The incidence of adverse events was similar between treatment groups. Ostarine showed a dose-dependent improvement in total lean body mass and physical function and was well tolerated. This study concluded that Ostarine may be useful in preventing and treating muscle loss associated with cancer and other chronic diseases.

A clinical study performed in 2007-2008 examined the effects of Ostarine on muscle loss and physical function in cancer patients. 159 patients were analysed for safety (placebo, n=52; Ostarine 1 mg, n=53; Ostarine 3 mg, n=54). The evaluable efficacy population included 100 participants (placebo, n=34; Ostarine 1 mg, n=32; Ostarine 3 mg, n=34). Compared with baseline, significant increases in total lean body mass by day 113 or end of study were noted in both Ostarine groups (Ostarine 1 mg median 1·5 kg, range −2·1 to 12·6, p=0·0012; Ostarine 3 mg 1·0 kg, −4·8 to 11·5, p=0·046). Change in total lean body mass within the placebo group (median 0·02 kg, range –5·8 to 6·7) was not significant (p=0·88). The most common serious adverse events were malignant neoplasm progression (eight of 52 [15%] with placebo vs five of 53 [9%] with Ostarine 1 mg vs seven of 54 [13%] with Ostarine 3 mg), pneumonia (two [4%] vs two [4%] vs three [6%]), and febrile neutropenia (three [6% vs one [2%] vs none). None of these events were deemed related to study drug. Both 1 mg and 3 mg of Ostarine resulted in increases in lean body mass in patients with advanced cancer, compared with baseline measurements. No significant changes from baseline were noted in patients assigned placebo. Adverse events were generally much the same between groups and were consistent with those for patients undergoing chemotherapy.

Ostarine may be useful in the treatment of diabetes

In the same clinical study (in 2007-2008) Ostarine also significantly reduced fasting glucose levels, and a trend toward reduction in blood insulin was observed. These effects resulted in a decrease in insulin resistance from baseline in the 1-mg and 3-mg treatment groups calculated based on the HOMA-IR. Of note, such decrease in insulin resistance was similar to that observed with metformin and glipizide, drugs used in the treatment of diabetes. Low levels of testosterone in men are associated with insulin resistance and type II diabetes, while testosterone therapy is known to improve metabolic parameters. This observation may have potential implications for the use of Ostarine in prediabetic or diabetic individuals, as commonly seen in patients with chronic kidney disease, chronic obstructive pulmonary disease, or metabolic syndrome. Compared to placebo, Ostarine also decreased total cholesterol, HDL, and triglycerides.

Ostarine and bodybuilding

Similar to anabolic steroids, Ostarine can help achieve significant muscle gains. However, its safety profile is significantly better compared to steroids. Ostarine has significantly fewer dangerous and undesirable side effects, and the potential health risks are many times lower than those that can be caused by steroid use. Therefore, Ostarine is often used (abused) by bodybuilders, athletes and people who are trying to achieve a muscular figure, want to achieve similar results as when using anabolic steroids, but also want eliminate / minimize possible unwanted side effects. Here, we consider it necessary to emphasize that Ostarine is not an approved nutritional supplement or stimulant for athletes. It is an experimental substance that is still under investigation, its long-term effects are not yet fully known and further research is needed. Keep in mind that Ostarine, like all our other products, is sold solely for scientific and research clinical use.

Ostarine and doping

WADA (World Anti-Doping Agency) banned all Selective androgen receptor modulators (including Ostarine) as early as 2008. Ostarine falls into the S1 Anabolic Agent category of banned substances in the WADA “Prohibited List”. There are many known cases of doping in sports with Ostarine among professional athletes, and the number of positive tests on Ostarine has increased in recent years.

Scientifically investigated possible benefits of Ostarine

• • Significant and selective anabolic effect on muscles and bones, without strong androgenic adverse effects on other organs
  • Can help treat serious diseases associated with muscle loss
  • May help in the treatment of osteoporosis
  • May be useful in the treatment of diabetes 
  • Helps build and maintain muscle mass
  • Increases bone mineral density
  • Reduces glucose levels and improves insulin sensitivity
  • Helps reduce excess fat

Advantages of Ostarine over Anabolic-Androgenic Steroids

• • Ostarine (MK-2866) is selective and primarily aimed at acting in muscles and bones. Due to this selectivity, unlike anabolic steroids, it does not cause strong androgenic negative effects on other organs
  • Similar to anabolic steroids, Ostarine can help achieve significant muscle gains, but has significantly fewer dangerous and undesirable side effects, and the potential health risks are many times lower than those that can be caused by steroid use:
    • • Ostarine does not convert on Estrogens or Dihydrotestosterone 
      • Ostarine does not cause Gynecomastia
      • Ostarine does not cause significant retention of water and salts
      • Ostarine does not cause increased Cortisol and Estrogen levels
      • Ostarine does not present a heavy load to the Liver
      • Ostarine does not cause prostate enlargement
      • Ostarine does not cause kidney disease
      • Ostarine does not cause acne and oily skin
      • Ostarine does not cause hair loss and baldness
      • Ostarine does not cause swollen face
      • Ostarine does not cause excess facial or body hair (hirsutism)
      • Ostarine does not cause sudden changes in mood
      • Ostarine does not cause irritability, nervousness, depression, restlessness
      • Ostarine does not cause aggression, explosiveness and psychological problems
      • Ostarine is highly effective when administered orally (no injections needed)

Ostarine known possible side-effects and risks

• • Suppressed levels of natural Testosterone in the body
  • May increase the risk of heart attack and stroke (mainly in the elderly)
  • The long-term effects of Ostarine are unknown

Ostarine (MK-2866) FAQ

What is Ostarine MK-2866?

SARM Ostarine (MK-2866) is a oral, nonsteroidal and Selective androgen receptor modulator, that was developed for treatment of conditions such as muscle wasting and osteoporosis. 

What does Ostarine do?

Ostarine was shown to increase lean body mass, decrease fat mass, and to modestly improve the homeostatic model assessment (HOMA), a measure of insulin sensitivity.

What is Ostarine used for?

Ostarine can help treat serious diseases associated with muscle loss and osteoporosis. But currently it is an that is still under investigation.

Does Ostarine build muscle?

The results of clinical trials conducted confirmed that Ostarine can help in increasing muscle mass, it has strong anabolic properties, and moreover, it act selectively only in tissues where it is required, in the muscles and bones.

Does Ostarine have strong side effects?

In clinical studies performed Ostarine appeared to be safe and well tolerated. It is highly selective and binds to androgen receptors in the body only where desired, in muscles and bones. Due to this selectivity, also its possible side effects are many times milder, less numerous and less dangerous compared to steroids.

Does Ostarine cause gynecomastia?

Ostarine does not cause Gynecomastia, because it does not interact with enzymes of aromatase.

Is Ostarine dangerous for the prostate?

Ostarine is selective for action only in muscle and bone, does not convert to dihydrotestosterone, therefore, unlike anabolic steroids, it does not pose a risk to the prostate.

Does Ostarine cause increased cortisol production?

Ostarine does not affect cortisol levels and does not increase its production in the body.

Is Ostarine banned in sports?

Yes, Ostarine falls into the S1 Anabolic Agent category of banned substances in the WADA “Prohibited List”.

Does Ostarine lower testosterone?

Ostarine may suppress the production and reduce the levels of natural Testosterone, but considerably less than some anabolic steroids. The effect on the reduction of testosterone production is also influenced by the size of the dose and the length of its use.

How safe is Ostarine?

In clinical studies conducted, Ostarine showed a dose-dependent improvement in total lean body mass and physical function and was generally well tolerated. It is the most and best clinically tested SARM to date.

Does Ostarine increase DHT?

Ostarine does not convert to estrogens and DHT. Because it has not a steroid structure, reductase and aromatase enzymes (which are responsible for the conversion of androgens to DHT and estrogens), are unable to join.

Ostarine dosage

A frequently used dose in clinical trials that showed a significant increase in lean body mass was 3 mg Ostarine daily. Among bodybuilders and users who have used (abused) Ostarine to build muscle mass and achieve a muscular figure, several time higher doses, in the range of 10-30 mg Ostarine per day are most often mentioned, in various online forums and internet discussions. Due to long half-life of Ostarine, one dose a day is enough.

We emphasize that Ostarine is not an approved nutritional supplement or stimulant for athletes. It is an experimental substance that is still under investigation and not all of its side effects may be known. Keep in mind that Ostarine, like all our other products, is sold solely for scientific and research clinical use.