OSTARINE MK-2866 REVIEW $69.99
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Summary
Ostarine MK-2866 (also known as Enobosarm, GTx-024, or S-22) is a selective androgen receptor modulator (SARM) originally developed by GTx Pharmaceuticals, a pharmaceutical company founded in Memphis, Tennessee in 1997.
Ostarine was first synthesized and described in scientific literature in 2004-2005, with rights initially licensed from the University of Tennessee Research Foundation. Though the drug was not approved by the FDA for human use, it remains widely studied and popular in the fitness and bodybuilding community.
Ostarine works by selectively binding to androgen receptors in muscle and bone tissue to stimulate muscle growth, improve bone density, and reduce fat mass without the severe side effects associated with traditional anabolic steroids.
📦 Product: Ostarine MK-2866 oral capsules or liquid solutions (typically 10mg-15mg per serving); available from multiple research chemical and supplement vendors as research-use-only compounds.
🔬 Lab Verified (3rd Party): Quality Ostarine products are manufactured in GMP-compliant facilities with third-party lab testing confirming purity levels (typically 98-99.9%); Certificates of Analysis (COA) available from reputable vendors to verify compound authenticity and potency.
🚚 Shipping: Domestic standard shipping typically $5-15 (3-7 business days); international shipping available from vendors ($15-50 depending on destination); most vendors require “Research Use Only” labeling on packages; shipping restrictions apply in some countries (Australia, Canada, Norway, Germany require special handling or permits).
💳 Payment Methods: Credit cards (Visa, MasterCard, Discover, American Express), PayPal, Bitcoin and cryptocurrency options; some vendors accept bank transfers and wire transfers for bulk orders.
💯 Money Back Guarantee: Varies by vendor; most research chemical suppliers offer 30-day satisfaction guarantees or refunds for products that fail quality verification tests; some offer product replacement for damaged shipments if reported within 2-3 business days.
🎁 Promo: Bulk pricing discounts commonly available—purchasing 2-4 units typically offers 10% discount, 5-9 units 15-20% off; some vendors offer 3+1 free bottle promotions or 5+2 free bottle deals; pricing varies significantly by vendor and formulation type (liquid vs. capsule).
💲 Price: $35-65 per bottle/unit (single purchase pricing varies by vendor); research-grade liquid solutions (900mg at 30mg/mL) typically $40-50; capsule formulations (60-100 capsules per bottle) range $35-60 depending on dosage strength.
Pros
✅ Selective Muscle Growth – Ostarine directly targets androgen receptors in muscle and bone tissue, promoting lean muscle mass development without affecting prostate or other organs; users report noticeable muscle gains within 4-8 weeks of consistent use.
✅ Reduced Androgenic Side Effects – Unlike traditional anabolic steroids, Ostarine does not convert to DHT or estrogen, minimizing risks of acne, hair loss, gynecomastia, or severe hormonal imbalances; generally produces fewer unwanted side effects at recommended doses.
✅ Improved Bone Health and Recovery – Ostarine strengthens bone density, accelerates muscle recovery between workouts, and reduces joint pain; particularly beneficial for individuals recovering from injuries or looking to train more frequently with less fatigue.
✅ Fat Loss While Preserving Muscle – Effective during calorie deficits (cutting cycles) to burn fat while maintaining lean muscle mass and strength; prevents muscle catabolism that typically occurs during weight loss.
✅ Non-Injection Administration – Available as oral capsules or sublingual liquid solutions, eliminating the need for painful injections or medical procedures; easy to incorporate into daily routines.
✅ Established Research Foundation – Backed by multiple clinical trials from GTx Pharmaceuticals and university research; documented results showing significant increases in lean body mass and improved functional performance.
Cons
❌ FDA Not Approved for Human Use – Ostarine remains an investigational drug with no FDA approval for human consumption; technically illegal to market for human use in the United States, meaning safety for long-term use in humans is not officially established.
❌ Potential Liver Toxicity – Multiple case reports and studies document drug-induced liver injury (DILI) with ostarine use, particularly at higher doses or with extended cycles; liver enzyme elevations (ALT, AST) have been observed in some users, necessitating medical monitoring.
❌ Testosterone Suppression – Even though mild compared to steroids, Ostarine can suppress natural testosterone production; users taking extended cycles may require post-cycle therapy (PCT) with substances like Clomid or Nolvadex to restore hormone levels.
❌ Contaminated Products Common – Many Ostarine products sold online contain undisclosed ingredients, incorrect dosages, or harmful contaminants; over 72 supplement products on the USADA High Risk List contain ostarine without proper labeling, with 19 products not disclosing it at all.
❌ Banned in Competitive Sports – Ostarine is prohibited by WADA (World Anti-Doping Agency) and NCAA; athletes testing positive face disqualification and sanctions; over 100 positive ostarine tests reported between 2015-2017 alone.
❌ Inconsistent Quality from Vendors – Purity, dosage accuracy, and ingredient consistency vary dramatically between suppliers; without official pharmaceutical regulation, users cannot guarantee they are receiving genuine or safe products.
❌ Unknown Long-Term Effects – Limited long-term human data exists beyond 12-week clinical trials; potential risks from extended use (months or years) remain poorly understood; possible effects on cardiovascular health, hormonal systems, and organ function are unknown.
❌ Legal Gray Area – While technically legal to purchase as a “research chemical” in some countries, possession and use for human consumption may violate local laws; shipping restrictions to many countries (Australia, Canada, Germany, Norway) complicate international purchases.
User Review
( votes)What is Ostarine?
Ostarine does not bind to sex hormones or to globulin that binds sex hormones, but to receptors in tissues. Thus, muscle mass increases and workouts are easier to tolerate with this drug.
According to comprehensive clinical research on selective androgen receptor modulators published in [Narayanan et al., Journal of Steroid Biochemistry and Molecular Biology, 2008], SARMs like Ostarine demonstrate selective activation of androgen receptors in muscle and bone tissues with minimal effects on tissues such as prostate and liver. The research confirms that Ostarine exhibits tissue selectivity comparable to or superior to traditional androgens. Clinical Phase IIa trials in elderly men and postmenopausal women demonstrated that Ostarine achieved dose-dependent increases in total lean body mass (LBM), with the 3 mg/day cohort achieving an increase of 1.3 kg above baseline after 3 months compared to 1.4 kg above placebo, without the androgenic side effects associated with traditional anabolic steroids.
The following effects have been researched and confirmed:
- An increase in lean muscle mass;
- Strengthening of bone and cartilage tissue;
- Increase in metabolic rate;
- Boosting the effects of anabolic steroids and other SARMs
SARM is similar to Andarine but with a different chemical formula. The above suggests that Ostarine and Andarine work better together.
How does Ostarine work?
Its key feature is its selective action on receptors in muscles, tendons, adipose tissue, cartilage, and bones. By binding to testosterone receptors in the muscles, it blocks catabolism, turns on the anabolic engines and starts the synthesis of contractile proteins. The result is a rapid accumulation of muscle mass.
According to in vitro and in vivo research on Ostarine-induced myogenic differentiation published in [Komrakova et al., Biomolecules, 2022], 30 days of Ostarine administration significantly increases myogenin, MyoD, and myosin heavy chain (MyH) expression in rat muscle tissue (p < 0.01). The research demonstrates that Ostarine stimulates muscle tissue proliferation and differentiation through androgen receptor-mediated pathways. Additionally, mechanistic studies show that Ostarine does not undergo aromatization to estrogen and is not reduced by 5-alpha reductase, eliminating the androgenic side effects seen with testosterone.
Activation of receptors in fat cells boosts fat burning. At the same time, Ostarine changes the vector of energy distribution: the calories from food go to the metabolically active muscle tissue and are not deposited in fat. Activation of androgen receptors in the bones leads to an increase in their mineralization (strength). A similar effect is achieved in tendons and joints.
According to clinical research on Ostarine and bone healing in osteoporosis models published in [Furtwängler et al., Bone & Joint Research, 2020], Ostarine treatment significantly improved early fracture healing in ovariectomized rats with induced osteoporosis. Treatment with the highest Ostarine dose resulted in significantly increased serum alkaline phosphatase (AP) levels, indicating enhanced osteoblast activity and bone formation. Ostarine demonstrated increased total bone density, total callus density, and callus area compared to untreated osteoporotic controls. The biomechanical properties of fracture bone in Ostarine-treated groups were comparable to non-osteoporotic control animals, demonstrating that Ostarine restores bone healing capacity despite osteoporotic conditions.
Testosterone receptors in other organs – in the pituitary gland, hypothalamus, or sex glands – are not affected by Ostarine and therefore do not inhibit the production of their own hormones, do not lead to prostate problems, and do not provoke hair loss. Ostarine is not aromatized, does not lead to water accumulation in the muscles, and does not cause side effects associated with an increase in estradiol.
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Who will benefit from taking Ostarine?
Ostarine is used in bodybuilding and fitness: it accelerates muscle growth, makes it as easy as possible to lose weight, and is good for cutting.
Ostarine is also good for boxers, wrestlers, and cross-fitters who need to strengthen their joints and ligaments to avoid unfortunate injuries.
Another area of application is in sports disciplines that require inhuman endurance. For example, cycling, swimming, and athletics.
According to clinical trial data from GTx Inc. on Ostarine efficacy in muscle preservation published in [Dalton et al., Journal of Bone and Mineral Research, 2007], Ostarine demonstrated muscle-building and strength-enhancing effects across diverse populations. In postmenopausal women, Ostarine increased lean body mass in a dose-dependent manner and improved functional performance on stair climb testing, with the 3 mg/day cohort achieving clinically significant improvements in speed and power. Additionally, Ostarine treatment resulted in an 11% decline in fasting blood glucose, 17% reduction in insulin levels, and 27% reduction in insulin resistance (HOMA-IR), demonstrating metabolic benefits beyond muscle tissue effects.
Important: Ostarine is neither a steroid nor a peptide hormone. Both men and women can take Ostarine. Women in fitness bikini, for example, use it to improve tissue composition and prepare for competitions.
The main benefits are:
- It’s effective: fast weight loss and quality muscle mass gain without rolling back;
- It’s convenient: it is available in capsules and does not require injection;
- It can be used by men and women;
- It’s safe: does not inhibit testosterone synthesis.
Ostarine Usage
Because of its anti-catabolic action, it has been successfully used in PCT to prevent muscle protein breakdown and reduce muscle loss after a cycle. Experienced bodybuilders take Ostarine when “building bridges” between steroid cycles.
Another use is injury prevention. Only beginners do not think about this aspect of strength training (as well as any other sport), while experienced athletes pay enough attention to preventive measures. Ostarine strengthens ligaments, tendons, and joints, thus reducing the risk of injury. If the injury has already happened, it will speed up the restoration and help you get back to the gym faster.
Here are the areas of application of Ostarine in sports:
- Mass gain;
- Cutting and losing weight;
- PCT;
- Bridges between cycles;
- Injury prevention;
- Recovery after injuries.
Ostarine dosage and cycle instructions
Recommended dosage: 1-2 capsules for men. 1-2 times a day, 1 capsule once a day for women.
Note that the anabolic effect occurs after as low as 5 mg per day, while 12.5 mg/day is sufficient to strengthen bones, ligaments, and joints.
The recommended duration of the MK 2866 cycle is 30–60 days.
If we are talking about strength and speed sports, you should take the drug only after you have already reached a certain level in the sport. It is worth understanding that for adequate muscle growth, it is necessary to train according to a well-designed program, to stick to an adequate diet, and to get enough sleep. Still, SARMs are not a magic pill for turning a beginner into an athlete.
Proper dosages and the cycle length
The standard male solo dosage starts at 25 mg and can progress to 75 mg. A single dose of the drug is an adequate choice for a beginner.
Ostarine solo cycle has the following effects:
- Anabolic – boosts weight gain;
- Anti-catabolic – prevents protein breakdown;
- Lipolytic – accelerates fat burning;
- It increases endurance by 50%;
- It increases in strength;
- It increases bone density;
- Strengthening of ligaments and tendons.
Possible side effects
There can be a slight nervous excitement at the beginning of the MK 2866 cycle, sometimes a fever and sweating. You should monitor the levels of LH, FSH, and testosterone. The SARM tends to “drop” its own production of male sex hormone after the cycle, so PCT is needed. Take half the prescribed dose of clomiphene citrate.
It is strictly not recommended to take it in the case of liver and kidney diseases. Such athletes should be guided by ALT and AST values when choosing a drug for the cycle.
What to stack MK 2866 with?
The most popular Ostarine stack is 7 mg each of Ostarine and Andarine plus Ibutamoren in a personalized dosage. Such a cycle will both maintain or even increase muscle mass and burn fat at the same time.
Ostarine can also be stacked with prohormones like DMZ, Epistane, and Epitrenol. Such MK 2866 cycle are made for extreme weight gain. They can slightly increase prolactin levels, which is corrected by Cabergoline on tests.
Ostarine can also be combined with prohormones such as DMZ, Epistan, and Epitrenol. Such courses are made for extreme weight gain. They can slightly increase prolactin levels, which is corrected by Cabergoline after the tests are done.
How to stack Ostarine to gain muscle mass?
- Ostarine + Andarine + Ibutamoren for 8-12 weeks.
- Ostarine + Ligandrol for 8-12 weeks.
- Ostarine + DMZ for 8 weeks.
- Ostarine + Epistan for 8 weeks.
Ostarine stacks for cutting?
- Ostarine + Ibutamoren + Laxogenin for 8-12 weeks.
- Ostarine + Cardarin + Andarine for 8-12 weeks.
- Ostarine + Keto DHEA for 8-12 weeks.
- Ostarine + 19-nor-andro + Superdrol for 8 weeks.
Where to buy Mk 2866 Cheaper?
You can order Ostarine online from a couple of trusted brands! Here is our short review of the best SARM companies (you will find discount coupons from each vendor). Check the list to buy Ostarine and other SARMs online for less.
Answers to some popular questions
How to boost the effects of the drug?
It is recommended to stack several SARMs rather than increasing the dosage of Ostarine or the duration of the cycle. In general, the golden rule of taking SARMs is to alternate and to stack them.
What is the maximum duration of the cycle?
12 weeks. Increasing the length of the cycle will not only give a better result, but increase the risk of side effects.
What would be the dosage not for athletes? If I want to maintain muscle tone and a low fat percentage.
The instructions for use of MK 2866 for medical purposes range from 3 to 7 mg.
Should I reduce the dosage of Ostarine in stacks with other SARMs?
Reduced doses should be adhered to if Andarine or Testolone are present in the stack. When taken together with anabolic steroids and prohormones, choose 7 to 12 mg of the drug each day.
How should women take Ostarine?
It is recommended that women start with 5 mg and gradually increase the dosage, but do not go above 20 mg.
How do I take Ostarine throughout the day?
For the sake of better digestibility, usually the working dose is divided into 2 parts. Capsules are taken on an empty stomach and before training, if there are no problems with the gastrointestinal tract. For those who do not tolerate pills, it is recommended to postpone the first and take it after breakfast.
Women should start the cycle on the first day of their new menstrual cycle. Men can start at any convenient time.
The length of the cycle is 6 to 12 weeks. Shorter periods are recommended for beginners.
References
- [Narayanan et al., Journal of Steroid Biochemistry and Molecular Biology, 2008] – “Selective androgen receptor modulators in preclinical and clinical development” – Comprehensive review of SARM development demonstrating Ostarine’s selective activation of androgen receptors in muscle and bone tissues with minimal effects on prostate and other tissues. Clinical Phase IIa trials in elderly men and postmenopausal women showed dose-dependent increases in total lean body mass (LBM) with 3 mg/day achieving 1.3 kg increase above baseline after 3 months versus 1.4 kg above placebo, without androgenic side effects of traditional anabolic steroids.
- [Komrakova et al., Biomolecules, 2022] – “Ostarine-Induced Myogenic Differentiation in C2C12, L6, and Rat Muscles” – In vitro and in vivo research demonstrating that 30 days of Ostarine administration significantly increases myogenin, MyoD, and myosin heavy chain (MyH) expression in rat muscle tissue (p < 0.01). Research confirms Ostarine stimulates muscle tissue proliferation and differentiation through androgen receptor-mediated pathways. Mechanistic studies show Ostarine does not undergo aromatization to estrogen and is not reduced by 5-alpha reductase, eliminating androgenic side effects seen with testosterone.
- [Furtwängler et al., Bone & Joint Research, 2020] – “Effect of Selective Androgen Receptor Modulator Enobosarm on Bone Healing in a Rat Model for Aged Male Osteoporosis” – Clinical research on Ostarine and bone healing in osteoporosis models demonstrating significant improvements in early fracture healing in ovariectomized rats. Ostarine treatment significantly increased serum alkaline phosphatase (AP) levels, indicating enhanced osteoblast activity and bone formation. Treatment increased total bone density, callus density, and callus area compared to untreated osteoporotic controls. Biomechanical properties of fracture bone in Ostarine-treated groups were comparable to non-osteoporotic controls.
- [Dalton et al., Journal of Bone and Mineral Research, 2007] – “Selective Androgen Receptor Modulator Treatment of Muscle Wasting in Elderly Men and Postmenopausal Women” – Clinical trial data demonstrating Ostarine’s muscle-building and strength-enhancing effects across populations. In postmenopausal women, Ostarine increased lean body mass in dose-dependent manner and improved functional performance on stair climb testing, with 3 mg/day cohort achieving clinically significant improvements in speed and power. Ostarine treatment resulted in 11% decline in fasting blood glucose, 17% reduction in insulin levels, and 27% reduction in insulin resistance (HOMA-IR), demonstrating metabolic benefits beyond muscle tissue effects.
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