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What You Need To Know Before You Buy Ostarine

Table of Contents
what you need to know before buying ostarine

Key Takeaways 

  • A full breakdown of Ostarine’s mode of action and chemical structure 
  • Groundbreaking clinical data and its history
  • Comparing Ostarine to other SARMs

What is Ostarine MK 2866

The SARM Ostarine, also known as MK-2866, was initially developed to be studied for laboratory research on its assumed capability to help with severe cancer-related cachexia, in promoting lean muscle mass production and skeletal density.

Cachexia is a complicated metabolic disorder marked by the loss of skeletal muscle and reduced physical function. This condition is linked to various chronic diseases, such as cancer, sarcopenia, chronic obstructive pulmonary disease, and end-stage renal disease, leading to significant health complications and mortality.

Ostarine exhibits tissue-specific effects in muscle and bone. Significantly, it does not affect other androgen-sensitive tissues, avoiding unwanted adverse effects.

Mechanism Of Action 

To better understand the mechanism of action of Ostarine, let’s dive deeper into the molecular mechanisms and physiological processes involved.

Ostarine exerts its effects by selectively binding to androgen receptors (ARs), nuclear hormone receptors found in various tissues.

The tissue-selective nature of Ostarine lies in its ability to preferentially bind and activate ARs in muscle and bone tissues while having minimal effects on other tissues such as the prostate, liver, and sebaceous glands.

This particular activity is thought to be due to differences in coactivator protein expression and the availability of ARs in various tissues.

Once Ostarine has activated the androgen receptors in muscle and bone cells, it triggers intracellular signaling cascades that promote anabolism

Some key pathways involved include the Akt/mTOR pathway, which stimulates protein synthesis and inhibits protein degradation, and the MAPK/ERK pathway, which promotes cell proliferation and differentiation. Collectively, these signaling events lead to increased muscle mass, strength, and bone density.

Analyzing the Chemical Structure and Pharmacokinetics of Ostarine

Ostarine is not approved by the FDA for human consumption and Sports Technology Labs does not condone the human use of said chemical or those relating to such. 

The importance of bioavailability is to be considered when Ostarine is tested amongst subjects. 

Ostarine (as seen above) has a complex chemical structure that has shown promise in its oral bioavailability within completed clinical trials.

Several aspects of chemical bonds influence the bioavailability of any given compound including a measure of molecular flexibility, the rotatable bond count

The sum of hydrogen bonds (donor and acceptor) have the responsibility of binding to ligands, which play a crucial role in androgen receptor function

When observed for its laboratory research use, Ostarine meets the criteria of high-performing oral bioavailability.

Clinical History of Ostarine 

Ostarine has been the subject of the most comprehensive clinical trials thus far

Ostarine’s effects on Lipid Metabolism of Wistar Rats 

Artificial androgen receptor (AR) ligands are commonly used for androgen deficiency. A notable consequence of androgen deficiency is the disruption of lipid metabolism homeostasis.

This research examined the impact of Ostarine on rat adipocyte metabolism using in vitro methods. Researchers incubated isolated rat adipocytes with various concentrations of Ostarine to study its effects.

A control incubation using testosterone, the natural ligand for androgen receptors, was used as a comparison. Androgen receptor inhibitors were employed to study Ostarine’s genomic activity.  The team assessed alterations in lipolysis and lipogenesis intensity and variations in leptin and adiponectin secretion.

This study examined the gene expression of leptin and adiponectin, revealing for the first time that Ostarine significantly influences lipid metabolism intensity. Ostarine reduces the expression of leptin and adiponectin mRNAs and their release from rat adipocytes.

Findings suggest that Ostarine, acting through androgen receptors, similarly impacts lipid metabolism regulation and endocrine function of mature rat adipocytes in vitro. These results emphasize the importance of additional research to explore the effects of selective androgen receptor modulators (SARMs) on the entire organism.

Ostarine in Ovariectomized Sprague-Dawley Rats 

Previous data on Ostarine along with LGD-4033 has shown its ability to improve physical function and increase muscle mass with a relatively low risk profile.

To investigate this, researchers conducted two experiments using ovariectomized rats as a typical model for postmenopausal conditions. 

In both experiments, 3-month-old Sprague-Dawley rats were separated into five groups, each containing 12 to 15 rats. 

One group of rats did not have their ovaries removed (Non-OVX), while four other groups had their ovaries removed (OVX) and weren’t administered Ostarine or LGD-4033 for eight or nine weeks.

Subsequently, three OVX groups received either Ostarine or LGD-4033 at varying quantities (0.04, 0.4, or 4 mg/kg body weight per day) over a period of five weeks. When the experiment ended, the rats’ uterus, gastrocnemius, and soleus muscles were weighed.

Also, things like muscle fiber size, blood vessel density, and enzyme activity (lactate dehydrogenase [LDH]., citrate synthase [CS]. a biomarker related to skeletal density, and complex I) were studied.

All rats that were administered Ostarine had more blood vessels in the gastrocnemius and longissimus muscles compared to Non-OVX and OVX rats, while all LGD-4033 subjects showed more blood vessels than the Non-OVX group. Neither SARM affected muscle fiber size or distribution patterns.

Ostarine was seen to increase citrate synthase (CS) in the longissimus muscle.

Both SARMs demonstrated an effect on the uterus. Overall, both SARMs positively influenced muscle blood supply, with a greater impact from Ostarine.

Phase ll trial of Ostarine in Patients with Cancer-induced Muscle Wasting 

Muscle loss due to cancer starts early, leading to reduced physical ability and other harmful clinical outcomes. This phase 2 study, which was randomized, double-blind, and placebo-controlled, evaluated the effectiveness and safety of Ostarine, a selective androgen receptor modulator, for those with cancer

The team included males (over 45 years old) and female (postmenopausal) cancer subjects who were not obese and had lost at least 2% of their weight in the past 6 months. Participants were randomly divided in a 1:1:1 ratio, using a computer-generated list, block size three, and sorted by cancer type to take either 1 mg or 3 mg of Ostarine or a placebo once a day for up to 113 days. The study took place at oncology clinics in the US and Argentina. 

The main goal was to measure the change in total lean body mass from the beginning of the study, using dual-energy x-ray absorptiometry. Effectiveness analyses were conducted only on subjects who had a baseline and an assessment within 10 days before the study started, or first received Ostarine, and within 10 days of day 113 or the end of the study (evaluable efficacy population). 

Adverse effects and other safety measures were examined in the intention-to-treat (safety) population. This trial is registered with under the number NCT00467844.

Out of 159 patients tested for safety (placebo: 52; Ostarine 1 mg: 53; Ostarine 3 mg: 54), 100 were included in the effectiveness analysis (placebo: 34; Ostarine 1 mg: 32; Ostarine 3 mg: 34). 

Both Ostarine groups showed notable increases in total lean body mass from the start to day 113 or the study’s end (Ostarine 1 mg: 1.5 kg on average, range: -2.1 to 12.6; Ostarine 3 mg: 1.0 kg on average, range: -4.8 to 11.5). The placebo group saw no significant change in total lean body mass (average: 0.02 kg, range: -5.8 to 6.7). 

None of the following adverse outcomes were considered related to the administration of Ostarine. Cancer growth (15% in the placebo group, 9% in the Ostarine 1 mg group, and 13% in the Ostarine 3 mg group), pneumonia (4% in both the placebo and Ostarine 1 mg groups, and 6% in the Ostarine 3 mg group), and fever with low white blood cell count (6% in the placebo group, 2% in the Ostarine 1 mg group, and none in the Ostarine 3 mg group). 

Ostarine’s effects on Muscle Wasting in Non-Small Cell Lung Cancer Patients (NSCLC) A Phase lll Trial Breakdown 

The study sought to assess the effectiveness and safety of Ostarine in promoting lean muscle mass in individuals with non-small cell lung cancer (NSCLC)

The study began in May 2011 and completed in March 2013. It was conducted at multiple locations across the United States, Europe, South America, and Asia. 

The study enrolled 648 participants aged 18 years or older diagnosed with stage III or IV NSCLC who were starting first-line chemotherapy. Participants were randomized to receive either Ostarine or a placebo, in addition to their standard-of-care chemotherapy. 

The primary outcome measures (what the investigator considers the most important measures) included the following: 

Lean body mass (LBM) responder rate at Day 84, defined as the percentage of subjects with an increase in LBM of ≥1 kg from baseline. 

LBM refers to the weight of everything in the body except fat, including muscle mass, bones, organs, and water. The LBM responder rate at Day 84 measures the proportion of participants who experienced an increase in their LBM of at least 1 kilogram (≥1 kg) from their initial LBM measurement (baseline) 84 days after administration.

A higher LBM responder rate would indicate that a greater percentage of participants experienced a significant increase in their lean body mass during the study.

Stair climb power (SCP) responder rate at Day 84, defined as the percentage of subjects with an increase in SCP of ≥10% from baseline. 

SCP is a measure of the ability to climb stairs, which can be an indicator of overall physical strength and endurance, particularly in the lower body muscles. SCP is typically calculated by considering the time it takes to climb a specific number of stairs, subject’s body weight, and the height of the stairs.

The SCP responder rate at Day 84 measures the proportion of participants who experienced an increase in their SCP of at least 10% (≥10%) from their initial SCP measurement (baseline) after 84 days.

A higher SCP responder rate would indicate that a greater percentage of subjects experienced a significant improvement in their stair climb power during the study, suggesting a positive impact on physical function and performance.

The results show that 62.0% of subjects in the Ostarine group experienced a significant increase in their LBM, compared to only 37.2% of participants in the placebo group. 

Suggesting that Ostarine was more effective than the placebo in the study population, as a higher proportion of subjects in the Ostarine group experienced a significant increase in lean body mass. 

The results show that 49.5% of participants in the Ostarine group experienced a significant improvement in their SCP, compared to only 28.7% of subjects in the placebo group. 

Ostarine was more effective than the placebo in improving physical function and muscle performance in the study population, as a higher proportion of participants in the Ostarine group experienced a significant increase in stair climb power. 

The primary outcome measures showed promising results. Secondary outcome measures included overall survival, progression-free survival, response rate, safety, and quality of life. However, there was no statistically significant difference in overall survival between the two groups. 

In conclusion, the study demonstrated that Ostarine significantly improved LBM and SCP in patients with NSCLC receiving chemotherapy but did not show a significant impact on overall survival. 

Ostarine’s Clinical Conclusion 

In conclusion, Ostarine has a long history of preclinical and clinical phase 1,2, and 3 phase studies evaluating its efficacy and safety. 

As said before, Ostarine has been the most studied SARM to date.

The laboratory research on Ostarine suggests the potential for muscle wasting conditions and cancer. Ostarine shows its positive effects on lean muscle mass, bone density, and muscle blood supply. Further research and larger trials are needed to fully understand its long-term safety and effectiveness.

Conclusion Question: How Do Other SARMs Compare to Ostarine? 

From a scientific standpoint, Ostarine holds the best data, comparatively to any other completed phase l or ll trial involving the experimentation of SARMs

Its chemical structure and pharmacokinetics allow it to be of efficient use in a clinical setting. Offering a bioavailability and structure that works well within test subjects, it seems to have small amounts of adverse outcomes in completed trials

Studies prove that Ostarine had stronger clinical results when compared to other SARMs. Data suggested the Ostarine group In the study discussed previously “Ostarine and Ligandrol Improve Muscle Tissue in a Ovariectomized Rat Model” exhibited the most effect in a pre-clinical setting compared to LGD-4033.

Ostarine vs RAD140 is another commonly discussed SARMs comparison, as they are among the most popular SARMs with some of the most clinical research.

Although technically a growth hormone secretagogue (GHS) MK 677 has been applied within laboratory research use alone and in conjunction with other secretagogues. MK 677 appears to have the same rate of the desired outcome. However, MK 677 is limited to ONLY having an effect on the release of growth hormone from the pituitary gland and isn’t seen to have a dramatic effect on protein synthesis in subjects in a critical state, while Ostarine does

Furthermore, Ostarine has shown groundbreaking effects in patients with Non-small cell lung cancer (NSCLC). While the effect on the overall survival of test subjects was unaffected, the symptoms that give the disease its harsh nature were shown to dramatically decrease. Ostarine improved the overall state patients were in prior to administration

In conclusion, Ostarine is the most clinically studied compound out of all SARMs. Its ability has been tested on hundreds of subjects in both preclinical and clinical settings. For more information, here are 5 questions about SARMS on Quora and why research is ongoing.

How Sports Technology Labs can Help!

When it comes to SARMs research, quality is king! Don’t be like some who have made the mistake of buying ostarine on etsy or other questionable sources. These are laboratory research chemicals and should only be purchased from vendors with adequate quality control practices. 

Don’t be hesitant to contact Sports Technology Labs for information or any questions/concerns about Ostarine (MK-2866), or other related research chemicals. Sports Technology Labs is the best place to buy Ostarine and offers the best vast selection of 3rd party tested SARMs and peptides with a minimum of 98% purity as confirmed by accredited third party US labs.

The lights are on 24/7 at Sports Technology Labs. With customer service that will assist you within one working business day. Feel free to contact us now.


Ostarine is not intended or approved for human consumption, and we do not condone the use of it as such. SARMs are for laboratory research use ONLY. Various studies discussed in this article are purely for the education of the reader on Ostarine’s clinical history in comparison to other studied research chemicals.

Scientific References:

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5. Veber DF, Johnson SR, Cheng HY, Smith BR, Ward KW, Kopple KD. Molecular properties that influence the oral bioavailability of drug candidates. J Med Chem. 2002 Jun 6;45(12):2615-23. doi: 10.1021/jm020017n. PMID: 12036371.

6. Uzzaman, M., & Uddin, M. N. (2019). Optimization of structures, biochemical properties of ketorolac and its degradation products based on computational studies. DARU Journal of Pharmaceutical Sciences27, 71-82.

7. National Center for Biotechnology Information (2023). PubChem Compound Summary for CID 11326715, Enobosarm. 

8. Bhasin, S. (2015). Selective androgen receptor modulators as function promoting therapies. The Journal of frailty & aging, 4(3), 121.

9. Leciejewska N, Pruszynska-Oszmalek E, Bien J, Nogowski L, Kolodziejski PA. Effect of ostarine (enobosarm/GTX024), a selective androgen receptor modulator, on adipocyte metabolism in Wistar rats. J Physiol Pharmacol. 2019 Aug;70(4). doi: 10.26402/jpp.2019.4.04. Epub 2019 Oct 19. PMID: 31642815.

10. Roch PJ, Henkies D, Carstens JC, Krischek C, Lehmann W, Komrakova M, Sehmisch S. Ostarine and Ligandrol Improve Muscle Tissue in an Ovariectomized Rat Model. Front Endocrinol (Lausanne). 2020 Sep 17;11:556581. doi: 10.3389/fendo.2020.556581. PMID: 33042018; PMCID: PMC7528560.

11. Dobs AS, Boccia RV, Croot CC, Gabrail NY, Dalton JT, Hancock ML, Johnston MA, Steiner MS. Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. Lancet Oncol. 2013 Apr;14(4):335-45. doi: 10.1016/S1470-2045(13)70055-X. Epub 2013 Mar 14. PMID: 23499390; PMCID: PMC4898053.

13. Dobs, A. S., Boccia, R. V., Croot, C. C., Gabrail, N. Y., Dalton, J. T., Hancock, M. L., … & Steiner, M. S. (2013). Effects of enobosarm on muscle wasting and physical function in patients with cancer: a double-blind, randomised controlled phase 2 trial. The lancet oncology, 14(4), 335-345.

14. Dalton JT, Taylor RP, Mohler ML, Steiner MS. Selective androgen receptor modulators for the prevention and treatment of muscle wasting associated with cancer. Curr Opin Support Palliat Care. 2013 Dec;7(4):345-51. doi: 10.1097/SPC.0000000000000015. PMID: 24189892.

15. Murphy MG, Bach MA, Plotkin D, Bolognese J, Ng J, Krupa D, Cerchio K, Gertz BJ. Oral administration of the growth hormone secretagogue MK-677 increases markers of bone turnover in healthy and functionally impaired elderly adults. The MK-677 Study Group. J Bone Miner Res. 1999 Jul;14(7):1182-8. doi: 10.1359/jbmr.1999.14.7.1182. PMID: 10404019.

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