In today’s article, I shall guide you about Ostarine or MK-2866, which is one of the mildest and safest SARM (selective androgen receptor modulator) available in the market. I’ve put together this guide to help you gain insight into the benefits of Ostarine, side effects, its dosage, and cycle.

What is Ostarine?

First and foremost, let me guide you with some basic details regarding Ostarine. It is also known as Enobosarm, MK-2866, and sometimes as GTx-024. The chemical name is quite complicated –n-(4-cyano-3-(trifluoromethyl)phenyl)-3-(4-cyanophenoxy)-2-hydroxy-2-methylpropanamide.  The molecular formula of-of Ostarine is C19H14F3N3O3 and it has a molecular weight of 389.334 g/mol.

Fig 1. Ostarine Chemical Structure

Ostarine was developed by a Memphis based pharmaceutical company called GTx Inc which was later bought over by Merck & Co.

Ostarine was initially developed to treat medical conditions like osteoporosis and muscle wasting to especially help patients recovering from cancer.

However, in recent years, it has gained immense popularity among the body-building fraternity to improve muscle growth and enhance strength.

Ostarine is an anabolic SARM drug that is usually taken orally, though it can be injected also.

Ostarine Pill

Did you know that Ostarine is not an anabolic steroid? It replicates the positive effects of steroids like improving stamina, building muscle tissue, and reducing fat but without the worry of negative effects of steroids like increased blood pressure and gyno. I personally feel that Ostarine is much safer than steroids.

How does Ostarine work?

Ostarine works like a typical SARM. Unlike steroids, a SARM like Ostarine stimulate the androgen receptors only of bone and muscle cells. They have a negligible effect on other cells of the body. So, it is successfully able to activate the muscle stem cells and help in the regeneration of muscles and also aid in muscle repair.

GTx-024 is also helpful in stimulating cells in connective tissues. It efficiently raises the IGF-1 (insulin-like growth factor 1 gene) to cause an increase in strength and muscle growth.

Ostarine also helps the body in the process of nutrient partitioning. This supports users to achieve fat loss while simultaneously gaining muscle mass.

In my opinion, the beauty of Ostarine is its amazing ability to target only the bone and muscle cells of the body. It has no effect on other organs like the reproductive organs, the brain, or the liver.  Since they are not able to break down into harmful molecules they do not have negative effects of anabolic steroids like DHT and estrogens.

Ostarine is also known to increase protein synthesis and nitrogen retention.

What are the benefits of Ostarine?

The most obvious positive results of ostarine are to help user’s combat osteoporosis and muscle waste issues.

However, there are many other positive side-effects of Ostarine that not many people are aware of. I would like to share with you the positive benefits of MK-2866.

The body-building and athletic community may benefit from taking Ostarine in not only building and cutting stage but also for recomping.

Lean Muscle

Ostarine can be helpful for gaining lean muscles or building as it is commonly known as among body-builders. It helps to gain a lean muscle mass with almost zero water retention.

Since Ostarine was originally developed to help patients with muscle loss problems, it is perfect for losing body fat or the cutting stage. One of the biggest problems with calorie reduction is that your body meets its nutrition requirement by taking the required nutrients not just from the fatty deposits but also from muscle mass. Unfortunately, this leads to a muscle loss problem. Ostarine helps you with your weight loss program, without worrying about muscle loss.

Ostarine is one of my favorite SARM’s as it helps with recomposition as well. Recomposition or recomping as it is commonly called can be quite complicated as it involves gaining muscles and losing body fat at the same time. Ostarine’s unique ability to undertake nutrition partition is especially helpful to users who are looking for help with recomping.

Ostarine’s nutrition partition effect helps the body in collecting calories and nutrition from fatty stores and fat deposits and then depositing it in muscle tissue. This makes the complex process of losing body fat and gaining muscles simultaneously much easier.

I think that Ostarine is also ideal for injury prevention. With the help of enhanced anabolic effect on the bone and muscle cells, Ostarine helps in the repair and rehabilitation of bone and muscle cells. It can be quite helpful in preventing injury or damage to joints and muscles if you are involved in extreme body-building activities.

I would also like to bring to your notice the many health benefits of Ostarine which are not known by most people.

One of the most underrated benefits of Ostarine is its help with osteoporosis.

Bone structure with Osteoporosis
Bone structure with Osteoporosis

Ostarine helps improve bone density and bone health. It can be especially helpful to seniors whose bones may become weaker with age and may face an increased risk of suffering from fractures.

Insulin Resistance: Since Ostarine is able to raise the IGF-1 (insulin-like growth factor 1 gene) it helps enhance insulin resistance and decrease blood sugar levels in the body. The effects of Ostarine are almost identical to anti-diabetic medication like metformin.

Ostarine also helps in reducing LDL and Triglyceride levels.

Ostaraine Side Effects

SARM’s like Ostarine have negligible side effects as compared to their heavy-duty friend’s, the anabolic steroids. Though its developer GTx has not disclosed any negative side effects of Ostarine, I would like to share some side-effects that I have noted after comparing notes and experiences of experts in the body-building community.

Sometimes Ostarine may result in high perspiration, and users may experience feeling hot and sweaty. Some users may also experience mild headache, back pain or joint ache. Very few people may complain of sleep disruption and mild nausea.

Ostarine may cause a feeling of lethargy in rare cases and users may feel weakness, and lack of energy or strength.

Ostarine may also cause Gynecomastia (man boobs) in extremely rare cases. If you are prone to gyno or have an extended history of suffering from gyno, you may restrict your Ostarine dosage to prevent gyno side effects.

Ostarine Cycle and Dosage

Like all SARM’s I would recommend that users should structure their Ostarine cycle in accordance with their usage motive. Ostarin is beneficial for all three body-building stages – bulking, cutting, and recomping. If you set up your Ostarine cycle according to your need you are sure to get the optimum results that you are looking for.

During the bulking cycle, a 25-30 mg daily dosage of Ostarine is sufficient if you are pairing it with another PCT. You may also take Ostarine between other steroid cycles for enhanced results. With less than a 30 mg dosage, you will benefit from improved strength and stamina, no water retention, and will be able to gain 6-8 pounds.

A typical bulking cycle would be 3-8 weeks with approximately 25-30 mg per day dosage. Women should not take more than 10mg a day. And the best thing about Ostarine, in my opinion, is that it doesn’t require need liver supplements to maintain a healthy liver.

Ostarine helps to prevent muscle loss and maintain muscle mass during the Cutting cycle. Ostarine is noted to provide stellar results for the cutting cycle with a dosage of lesser than 20 mg per day. I would recommend a dosage of about 15-20 mg for men for about 4 to 8 weeks during the cutting cycle. Women should keep their Ostarine dosage to about 5-10 mg per day.

Though there is no problem in following a twelve-week cycle for Ostarine, I usually recommend an eight-week cycle. With an eight week cycle, I’ve observed optimum results and almost no side-effects.

Also, I would recommend a minimum four-week break between two consecutive cycles. If possible, try to take a break equivalent to the number of weeks of your cycle.

The half-life of Ostarine is approximately 23.8 hours. I would recommend a single dosage per day to maintain a healthy blood serum concentration level. Ostarine is available both in tablet form as well as a liquid solution.

I strongly recommend users to keep their Ostarine dosage to less than 30mg per day. With a high dose of 50mg, you may be at risk of experiencing ostarine suppression. Similarly, a cycle of more than 12 weeks will also increase your chances of ostarine suppression. It is best to maintain a healthy cycle and dosage for healthy and safe usage of Ostarine.

Ostarine: Before and After Results

I’ve attached a picture to explain the benefits of Ostarine.

Ostarine - Before and After Results
Ostarine – Before and After Results

A typical Ostarine cycle would not only help to reduce fat deposits but also helps build up an enviable muscle mass. I can see a significant increase in vascularity levels. A person who has taken about 20mg daily dosage of Ostarine for 6-8 can benefit significantly in increasing lean body mass (LBM). Along with such gains, you are sure to benefit from healthy weight loss and improved strength levels.

Where can you buy Ostraine from?

Since Ostarine is still in the patent stage, it is not available commercially in the United States. It can be easily obtained online from countries where the sale is allowed for commercial or scientific research purpose. I would recommend that you take adequate precaution about the source as well as domestic laws before ordering Ostarine for personal use.


Ostarine is a relatively safer option than anabolic steroids. Though it may not be as effective as steroids, it definitely has fewer side-effects. With a balanced Ostarine dosage and cycle, Ostarine has multi-purpose benefits for body-builders and also helps in improving your lipid profile, sugar levels, and bone density.

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Matt Williamson
My name is Matt - fitness freak by choice. I intensively study and write about nutrition and health related topics. After reading and researching intensively on human health, I aspire to proliferate the wisdom that I acquired in a simple way.