Ostarine (MK 2866)
Muscle Preservation SARM
£45.00
What’s Included
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60 capsules per bottle -
10mg pure MK2866 per capsule
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2-month supply (1 cap daily)
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Third-party lab certificate included
Lab Tested
Third-party verified
Fast Shipping
3-7 business days
24/7 Support
Expert guidance
Product details
Buy Ostarine UK: Ostarine (MK 2866) for sale online at CORE, delivered in the UK as 60 x 10mg capsules, third-party lab tested, with the certificate included. Ostarine is a widely used SARM, known for its ability to preserve muscle mass during cutting phases while promoting lean gains during bulking. It’s the perfect introduction to SARMs for beginners and an essential tool for experienced users.
Our premium Ostarine is manufactured to the highest pharmaceutical standards and undergoes rigorous third-party testing. Each capsule contains 10mg of pure MK2866 for optimal results with minimal side effects.
The Most Versatile SARM Available
Ostarine MK-2866’s versatility is what sets it apart from every other SARM on the market. While most compounds excel in one specific context, Ostarine performs reliably across all three primary goals: lean bulking, cutting, and injury recovery.
This makes it the most practical all-around SARM available, and the reason it remains the highest-selling compound in its class.
Active Ingredients
Purity & Quality
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Third-party lab tested -
99.7%+ purity guaranteed -
24-month shelf life
Ostarine MK2866 works by selectively binding to androgen receptors in muscle and bone tissue, promoting anabolic activity while minimizing androgenic side effects. This selective action makes it ideal for both muscle building and preservation.
The compound increases protein synthesis and prevents muscle catabolism, making it particularly valuable during caloric restriction or intense training periods. Its mild nature and excellent safety profile make it suitable for longer cycles.
With a half-life of 24 hours, Ostarine MK2866 provides consistent anabolic support throughout the day, helping maintain muscle mass and strength even in challenging conditions.
Key Actions
Muscle Preservation During a Cut
During a cut, Ostarine’s anti-catabolic properties are its standout quality. Even at modest doses, users maintain muscle mass and strength that would otherwise be lost during aggressive caloric restriction.
This effect is well-established in the clinical literature. A Phase 2 trial published in The Lancet Oncology reported statistically significant preservation of lean body mass in cancer patients with muscle wasting compared with placebo. [1]
Read our guide to the ultimate cutting stack featuring Ostarine.
Lean Bulking
For lean bulking, Ostarine produces gradual, high-quality gains without the bloat associated with wet compounds. Gains are typically slower than those seen with RAD-140 or LGD-4033, but cleaner and more sustainable.
Key advantages for lean bulking:
- Minimal water retention.
- No aromatisation to oestrogen.
- Suitable for longer cycles due to a mild side-effect profile.
- Consistent anabolic support with a 24-hour half-life.
Joint and Connective Tissue Effects
Ostarine also has documented effects on bone and connective tissue. Preclinical research in an ovariectomised rat model found that Ostarine maintained bone mineral density and increased bone strength at intermediate and higher doses. [2]
Users frequently report reduced joint discomfort during training, particularly at the knee and shoulder. This is consistent with its receptor activity in bone and connective tissue.
Side effects at standard doses are mild. Temporary testosterone suppression is the most commonly reported variable on longer cycles. All CORE SARMS Ostarine is third-party tested to 99.7%+ purity. Sold strictly for research purposes.
Ostarine is often the first compound people try, since it performs reliably across bulking, cutting, and recovery goals alike. New to this? Start with our Complete Beginner’s Guide to SARMs.
Real results from real customers
Transformations from verified customers. Individual results vary.
Reviews
Rated 4.9 by verified UK buyers.
What are the Key Benefits of Ostarine (MK 2866)?
Muscle preservation
Lean gains
Enhanced recovery
Joint health support
Improved strength
Body recomposition
Ostarine Dosage: How to Use Ostarine (MK 2866)?
Dosage
10mg once daily
Timing
Take with morning meal
Cycle Length
8-12 weeks followed by 4-week break
Important
Dietary supplement use only
Very well tolerated. Can be used for cutting or lean bulking phases.
Training
Fits full-body routines or a standard split. Consistency in sets and progression matters more than the program you pick.
Diet
Eat at maintenance, a small surplus, or a small deficit, depending on your goal. Ostarine is the easiest compound to pair with flexible eating.
Stacking and cycle guidance
Ostarine is versatile enough to suit a range of goals, from bulking to cutting. Pick a single companion below to stack with Ostarine and save 5%, or choose a complete bundle further down for a bigger discount:
Cardarine (GW501516) + Ostarine (MK 2866)
Recomposition: Cardarine's fat-burning support pairs with Ostarine's muscle-preserving effect for a clean recomp.
£90.25 £95.00 Save 5%
Ostarine 15-20mg each morning. Cardarine 5-10mg, 1-2 hours before training. Run together for 8 weeks. PCT optional depending on Ostarine dose.
Ibutamoren (MK 677) + Ostarine (MK 2866)
Recomposition: Ostarine's lean muscle-and-fat-loss profile pairs well with MK-677's round-the-clock support.
£88.35 £93.00 Save 5%
Ostarine 15-20mg each morning. MK-677 10-25mg, 30-60 minutes before bed. Run together for 8-12 weeks. PCT optional for the Ostarine portion depending on dose.
MK 677 side effects, benefits and dosage guide
S23 (SARM) + Ostarine (MK 2866)
Cutting insurance: S-23's potent cutting effect pairs with Ostarine's muscle retention for extra insurance during a deficit.
£85.50 £90.00 Save 5%
Ostarine 15-20mg + S-23 10-20mg, both once daily each morning. Run together for 6-8 weeks. PCT mandatory for the S-23 portion.
Complete Bundles
Prefer a full protocol in one order? These pre-built bundles pair Ostarine (MK-2866) with 3-4 companions at a bigger combined discount:
Muscle Building Bundle
Complete stack: RAD-140, LGD-4033, Ostarine, and MK-677 bundled for less than buying each on its own.
£165.00 £185.00 Save 11%
LGD-4033 10-20mg, RAD-140 20mg, and Ostarine 20mg together each morning; MK-677 20mg before bed. Run for 8 weeks, never longer than 10. PCT required after.
Cutting Bundle
Complete stack: RAD-140, Ostarine, and Cardarine bundled into a complete cutting protocol, priced below buying each alone.
£130.00 £145.00 Save 10%
RAD-140 and Ostarine (10mg each) together each morning; Cardarine 10mg 1-2 hours before training. 6-8 weeks max. PCT required for the RAD-140 portion.
The CORE SARMS Handbook walks through dosing, cycle length, and stacking logic for every compound on this page.
Read the CORE SARMs Handbook →Post-cycle support
Frequently Asked Questions
Contact supportOstarine, also known as MK 2866 or Enobosarm (and often misspelled osterine), is a selective androgen receptor modulator known for muscle preservation and lean gains.
Yes, Ostarine is considered the best SARM for beginners due to its mild effects and excellent safety record.
Absolutely. Ostarine is excellent for preserving muscle mass during caloric deficits and cutting phases.
Expect lean muscle gains, improved recovery, maintained strength during cuts, and overall body recomposition.
Ostarine before and after results vary with diet, training and individual response. Users typically report better strength retention and leaner gains over an 8-12 week cycle, not dramatic overnight changes. Individual results vary.
Ostarine side effects may include mild fatigue, mood changes, or temporary hormonal shifts, including a temporary drop in natural testosterone. Not everyone experiences these, but they are possible. For the full picture, read our guide to SARMs side effects.
Typical cycles range from 8-12 weeks, followed by a 4-week break before starting another cycle.
Yes, Ostarine (MK-2866) can cause a temporary suppression of natural testosterone production during a cycle, especially at higher doses or extended use. The effect is usually mild and reversible once the cycle is complete.
Ostarine has a half-life of around 24 hours, meaning it stays active in the body for a full day. However, trace amounts may remain detectable for up to several weeks after discontinuation, depending on dosage, metabolism, and individual factors.
No, Ostarine is not a steroid. It is a Selective Androgen Receptor Modulator (SARM) that mimics some of the muscle-building benefits of anabolic steroids but with fewer side effects. Unlike steroids, Ostarine selectively targets muscle and bone tissue without significantly impacting other organs.
The standard Ostarine dosage on this page is 10mg once daily, taken with a morning meal. A typical cycle runs 8-12 weeks, followed by a 4-week break.
You can buy Ostarine UK directly from CORE. Each bottle holds 60 x 10mg Ostarine (MK 2866) capsules, a 2-month supply at 1 capsule daily, with a third-party lab certificate included. UK orders typically arrive in 3-7 business days.
Related products
Muscle Building Bundle
Complete muscle building stack: Ligandrol, Testolone, Ostarine, Ibutamoren
Sources:
[1] Dobs, A. S., Boccia, R. V., Croot, C. C., et al. (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. https://doi.org/10.1016/S1470-2045(13)70055-X
[2] Hoffmann, D. B., Komrakova, M., Pflug, S., et al. (2019). Evaluation of ostarine as a selective androgen receptor modulator in a rat model of postmenopausal osteoporosis. Journal of Bone and Mineral Metabolism, 37(2), 243-255. https://doi.org/10.1007/s00774-018-0929-9
