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What is Ostarine?
Ostarine, also known as enobosarm, S22, or MK2866, is a selective androgen receptor modulator (SARM) that has garnered significant attention in recent years due to its potential therapeutic applications and performance-enhancing properties. Unlike traditional anabolic steroids, SARMs like ostarine are designed to selectively target androgen receptors in muscle and bone tissues, minimizing unwanted side effects on other organs. Other names include: Enobosarm, GTx-024, MK-2866, S-22.
Effects on Muscle Tissue
Ostarine has been shown to stimulate muscle tissue proliferation and differentiation. Studies using C2C12 and L6 cells, as well as rat muscle tissues, have demonstrated that ostarine increases the expression of myogenin, MyoD, and MyH, which are key markers of muscle differentiation. This effect is mediated through the activation of androgen receptors and ERK1/2 kinase1. In ovariectomized rat models, ostarine treatment resulted in increased muscle mass and improved muscle vascularization, although it did not significantly change muscle fiber size or distribution patterns4.
Therapeutic Potential
Ostarine has shown promise in clinical trials for conditions such as cancer cachexia, a syndrome characterized by severe muscle wasting and weight loss in cancer patients. Phase I and II clinical trials have indicated that ostarine can increase lean body mass, enhance functional performance, and reduce fat tissue percentage with minimal side effects on other organs5. However, more extensive data is required to confirm its efficacy and safety for widespread clinical use.
Detection and Regulation
Due to its performance-enhancing properties, ostarine is banned by the World Anti-Doping Agency (WADA) under the category of “other anabolic agents”2. Detection methods have been developed to identify ostarine in biological samples such as nails and hair, demonstrating its long-term use in athletes2. Additionally, a UHPLC method has been validated for the quantitative determination of ostarine in dietary supplements, ensuring the accuracy and safety of these products for consumers8.
Other Applications
Interestingly, ostarine has also been identified as a potential anti-virulence agent against Pseudomonas aeruginosa, a common pathogen. It interferes with quorum sensing systems, reducing the production of virulence factors like pyocyanin without exerting bactericidal effects7. This novel application highlights the diverse potential of ostarine beyond muscle enhancement.
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🏢Is ostarine banned by the World Anti-Doping Agency (WADA)?
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Ostarine Chemical Structure and Mechanism of Action
Ostarine is a non-steroidal compound with an aryl-propionamide structure. It is not subjected to the typical steroid transformations of aromatization and reduction by 5α-reductase, which are common in anabolic steroids1. The crystal structure of ostarine has been determined, revealing that it crystallizes in the monoclinic system, P21 space group, with hydrogen bonds playing a crucial role in its molecular self-assembly3.
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🕸️What is Ostarine mechanism of action?
Uses of Ostarine
Muscle Proliferation and Differentiation
Ostarine stimulates muscle cell proliferation and differentiation by increasing the expression of myogenin, MyoD, and MyH, and this effect is mediated through the androgen receptor1 7.
Cancer Cachexia
Ostarine has shown promising results in increasing lean body mass, enhancing functional performance, and decreasing fat tissue percentage in patients with cancer cachexia, potentially offering a new strategy for managing this condition2.
Anti-Virulence Agent
Ostarine can act as an anti-virulence agent by interfering with quorum sensing systems in Pseudomonas aeruginosa, reducing the production of virulence factors like pyocyanin without bactericidal action3.
Performance Enhancement
Ostarine is used for performance enhancement due to its anabolic effects and minimal androgenic side effects, making it popular among athletes despite being banned by the World Anti-Doping Agency (WADA)4.
Postmenopausal Muscle and Bone Health
In postmenopausal models, Ostarine improves muscle mass, capillary density, and certain metabolic activities, and shows potential benefits for bone health by improving bone mineral density and volume density7 9.
Lipid Metabolism
Ostarine affects lipid metabolism by downregulating the expression and release of leptin and adiponectin from adipocytes, similar to the effects of testosterone8.
Obesity and Metabolic Parameters
While Ostarine lowers cholesterol levels, it does not significantly enhance the metabolic effects of exercise in obese rats, indicating limited benefits for metabolic parameters in this context6.
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🚀Can ostarine increase lean body mass in patients with cancer cachexia?
💎Does ostarine improve bone mineral density in postmenopausal models?
Adverse Effects of Ostarine
No Significant Metabolic Improvement: Ostarine did not show significant improvements in metabolic parameters in obese rats, even when combined with exercise. This suggests limited efficacy in enhancing metabolic health1.
Increased Uterine Weight: In a study on postmenopausal osteoporotic rats, ostarine treatment led to an increase in uterine weight, indicating potential hormonal side effects2.
Elevated Serum Phosphorus Levels: Ostarine treatment resulted in increased serum phosphorus levels in intermediate and high-dose groups, which could have implications for mineral balance and kidney function2.
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🌌What are the adverse effects of Ostarine?
How has Ostarine (Enobosarm) Improved Patient Outcomes?
Improvement in Lean Body Mass in Cancer Patients
Enobosarm significantly increased total lean body mass in cancer patients compared to placebo, suggesting its potential to counteract cancer-induced muscle wasting without the toxic effects associated with traditional androgens and progestational agents1.
Bone Healing in Osteoporosis
Enobosarm showed mixed results in bone healing in an aged male osteoporosis rat model. Prophylactic treatment with Enobosarm increased callus area and density but also increased prostate weight. Therapeutic treatment post-fracture negatively affected bone healing by reducing callus density and delaying osteotomy bridging2.
Efficacy in Metastatic Breast Cancer
In a Phase 2 study, Enobosarm demonstrated a clinical benefit rate of 50% and an overall response rate of 30% in patients with AR+ ER+ HER2- metastatic breast cancer who had progressed on standard endocrine therapy with a CDK 4/6 inhibitor. The treatment was well tolerated and showed significant positive effects on quality-of-life measurements3.
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🎗️Can ostarine significantly increase lean body mass in cancer patients without toxic effects?💆♂️How has Ostarine (Enobosarm) improved patient outcomes?
Common Complaints Associated with Ostarine (Enobosarm)
Liver Injury
Ostarine has been linked to drug-induced liver injury (DILI), presenting with symptoms such as jaundice, pruritus, and elevated liver enzymes1 2.
Cardiovascular Issues
There are reports of acute myocarditis associated with the use of Ostarine, indicating potential cardiovascular risks1.
Tendon Damage
Users of Ostarine have experienced tendon ruptures, suggesting that the compound may negatively affect tendon health1.
Contamination and Mislabeling
A significant number of Ostarine samples available for purchase are contaminated or mislabeled, which can lead to unexpected side effects and health risks1.
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🦴Is ostarine associated with an increased risk of tendon ruptures?
Disclaimer
The content in this blog post was generated using Consensus, an AI-powered academic search engine, and is based on publicly available scientific literature. While we strive to provide accurate, up-to-date, and well-researched information, this content is intended for informational and educational purposes only.
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Use of this information is at your own risk. Where provided, citations link to original scientific studies for reference only—these should be reviewed independently and interpreted with the support of a qualified medical or research professional.
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