MK-2866 vs RAD-140: Comparing Benefits & Side Effects

MK-2866 vs RAD-140: Everything you need to know

When it comes to selective androgen receptor modulators (SARMs), two popular options that often come up in discussions are MK-2866 (Ostarine) and RAD-140 (Testolone). These compounds have gained a lot of attention for their potential benefits in muscle growth, strength gains, and fat loss. 

However, it's important to understand their similarities and differences, including their benefits and side effects, before deciding which one to incorporate into your fitness routine. 

In this article, we will compare MK-2866 and RAD-140, examining their benefits and potential side effects, so you can make an informed decision based on factual data.

Introduction to MK-2866 and RAD-140

MK-2866 (Ostarine) and RAD-140 (Testolone) are both members of the SARMs family, which stands for selective androgen receptor modulators. These compounds interact with the androgen receptors in the body, primarily in muscles and bones, to promote muscle growth and enhance strength.(1)

Both MK-2866 and RAD-140 have their unique benefits and effects on muscle growth and strength enhancement.

Overview of MK-2866

MK-2866, also known as Ostarine or Enobosarm,(2) is a selective androgen receptor modulator (SARM) that is known for its potential to promote muscle growth and enhance strength. It was originally developed to treat muscle wasting diseases and promote bone health in older individuals.

Ostarine works by binding to androgen receptors in the body, which results in an increase in protein synthesis and ultimately leads to muscle growth. It also helps to prevent muscle breakdown, making it an ideal compound for athletes and bodybuilders looking to improve their performance and physique.

Users of MK-2866 report improved recovery times, allowing for more frequent and intense workouts. Studies have also shown that this SARM is able to improve bone health. Additionally, it has also shown potential in promoting joint healing and relieving joint pain.

It's important to note that while MK-2866 has been well-tolerated in studies, it may still have some mild side effects such as testosterone suppression. 

Overview of RAD-140

RAD-140, also known as Testolone, is a selective androgen receptor modulator (SARM) that is highly regarded for its potential benefits in both the medical and athletic communities. It is primarily known for its strong anabolic effects, making it a popular choice for individuals looking to increase muscle mass and strength.

One of the key advantages of RAD-140 is its ability to target androgen receptors in the muscle and bone tissues without significantly affecting other organs, such as the prostate or liver. This makes it a safer alternative to traditional anabolic steroids.

In addition to its anabolic effects, RAD-140 has also been found to have neuroprotective properties.(3) It has the potential to protect brain cells from damage and improve overall brain health. This makes it a promising compound for potential therapeutic applications in neurodegenerative diseases.

RAD-140 is also known to increase endurance and stamina, allowing athletes and fitness enthusiasts to push themselves harder during training sessions. The compound promotes efficient energy utilization, leading to improved athletic performance.

Overall, RAD-140 offers a unique combination of anabolic effects, neuroprotection, and enhanced endurance. It is a versatile compound that can provide valuable benefits for both athletes and individuals seeking to improve their overall health and well-being.

MK-2866 vs. RAD-140 Effects and Benefits

When comparing the effects and benefits of MK-2866 and RAD-140, both selective androgen receptor modulators (SARMs) have their unique advantages. The choice between MK-2866 and RAD-140 ultimately depends on personal goals and safety profile preferences.

MK-2866 Effects and Benefits

MK-2866, also known as Ostarine or Enobosarm, is a selective androgen receptor modulator (SARM) that offers several benefits for users. Some of the key effects and benefits of MK-2866 include:

  • Lean Muscle Mass: MK-2866 is known for its ability to promote lean muscle growth and increase muscle strength. It stimulates the androgen receptors in the muscles, leading to enhanced protein synthesis and muscle hypertrophy.
  • Bone Strength: In addition to its muscle-building properties, MK-2866 also helps improve bone health. It increases bone density and strength, making it beneficial for individuals with bone-related issues or muscle wasting diseases.
  • Minimal Side Effects: Compared to traditional anabolic steroids, MK-2866 has fewer side effects. It is considered as being relatively well-tolerated, with minimal impact on hormone levels, such as testosterone suppression.

Ultimately, the effects of MK-2866 depend on various factors, such as dosage, duration of use, and individual response. 

RAD-140 Effects and Benefits

RAD-140 (Testolone) is a selective androgen receptor modulator (SARM) that has gained popularity among athletes and bodybuilders due to its anabolic effects and potential benefits. Here are some primary effects and benefits of RAD-140:

  • Rapid Muscle Gain: RAD-140 is known for its ability to stimulate muscle growth and promote lean muscle mass. It works by binding to specific androgen receptors in the body, which leads to an increase in protein synthesis and muscle hypertrophy.
  • Brain Health: RAD-140 has shown potential neuroprotective effects, which means it may help protect brain cells and improve cognitive function. Studies have suggested that RAD-140 may have therapeutic applications in the treatment of neurodegenerative diseases.
  • Strength Increase: RAD-140 is known for its ability to enhance muscle strength and power. Users may experience significant improvements in their overall strength, which can be beneficial for athletes looking to improve their performance.

It is important to note that RAD-140, like other SARMs, is still under investigation, and more research is needed to fully understand its long-term effects and potential risks. 

Overall, RAD-140 shows promise in terms of muscle gain, brain health, and strength enhancement, but further research is necessary to fully understand its effects.

MK-2866 vs. RAD-140 Side Effects

MK-2866 and RAD-140 are both selective androgen receptor modulators (SARMs) that are often used for muscle growth and strength enhancement. While both compounds offer numerous benefits, they may also come with potential side effects.


  • Minimal risk of testosterone suppression: MK-2866 is known for its mild impact on natural testosterone levels, which makes it a popular choice for individuals looking to avoid hormonal imbalances.
  • Low risk of liver toxicity: Unlike many other performance-enhancing substances, MK-2866 has minimal hepatotoxicity, making it a safer option for long-term use.
  • Rare occurrence of mood changes: Some users have reported slight mood swings or irritability while taking MK-2866, but these effects are mild and temporary.


  • Potential testosterone suppression: RAD-140 can cause suppression of natural testosterone production. To prevent hormonal imbalances, users often incorporate a post-cycle therapy (PCT) regimen after a RAD-140 cycle.
  • Limited data on liver toxicity: The long-term effects of RAD-140 on liver health are still not well understood. However, short-term studies suggest a low risk of liver toxicity.
  • Minimal occurrence of mood changes: RAD-140 is less likely to cause mood swings or changes in behavior compared to other androgenic compounds.

It's important to note that individual reactions to these substances may vary, and users should consult with a healthcare professional before starting any SARMs regimen. 

Additionally, adhering to recommended dosages and cycling protocols can help minimize the potential side effects associated with MK-2866 and RAD-140.

RAD-140 vs. MK-2866 Bodybuilding Results

When it comes to bodybuilding results, both RAD-140 and MK-2866 have proven to be effective in improving muscle gain, fat loss, and workout recovery. However, there are some differences in the specific benefits they offer:


  • Known for its rapid muscle gain effects, RAD-140 can help users achieve substantial increases in lean muscle mass.
  • It also has anabolic effects, promoting increased strength and endurance during workouts.
  • Additionally, RAD-140 has shown potential neuroprotective effects, which can contribute to improved brain health and cognitive function


  • MK-2866 is favored by many bodybuilders for its ability to promote lean muscle mass without significant water retention or bloating.
  • This is one of the best SARMs for the cutting cycle, due to its ability to burn body fat without the same negative effects as anabolic steroids.
  • It also helps strengthen bones, making it beneficial for individuals with bone health concerns.
  • MK-2866 is known for its minimal side effects, making it a popular choice among athletes and bodybuilders.

When comparing the bodybuilding results of RAD-140 and MK-2866, it's important to consider personal goals, safety profiles, and effectiveness. 

While RAD-140 provides faster muscle gain, while the benefits of Ostarine (MK-2866) offer a smoother and more controlled muscle-building process.

Similarities and Differences Between MK-2866 and RAD-140

When comparing the effects of Osterine (MK-2866) and Testolone  (RAD-140), both offer unique benefits, whilst also sharing some similarities. For example, like Ostarine, Testolone is also a SARM (Selective Androgen Receptor Modulator) and they both work by stimulating your body's natural production of testosterone and human growth hormone (HGH).

Below is a summary of the similarities and differences between these two performance enhancing supplements. 


  • Selective androgen receptor modulators (SARMs): Both MK-2866 and RAD-140 are SARMs, which means they selectively bind to androgen receptors in the body.
  • Anabolic effects: Both compounds have strong anabolic effects, promoting muscle growth, strength, and performance enhancement.
  • Results: Both MK-2866 and RAD-140 are known for their muscle-building properties, making them popular choices for bodybuilders and athletes.
  • Side effects: While SARMs are safe alternatives to traditional anabolic steroids, both MK-2866 and RAD-140 have the potential to cause side effects, including testosterone suppression and mood changes.


  • Usage: MK-2866 (Ostarine/Enobosarm) is commonly used to treat muscle wasting diseases and promote bone health, while RAD-140 (Testolone) is often used for its neuroprotective effects and anabolic effects.
  • Results: MK-2866 is known for promoting lean muscle mass and improving bone strength, with minimal side effects. RAD-140, on the other hand, is associated with rapid muscle gain, increased strength, and potential brain health benefits.
  • Specificity: MK-2866 is considered to be one of the mildest SARMs, with fewer and milder side effects compared to RAD-140.

It's important to note that the effects and benefits of RAD-140 and Ostarine vary from person to person, and individual goals and safety profiles should be taken into consideration when choosing between the two.

Final Verdict

After comparing the benefits and side effects of MK-2866 and RAD-140, it's clear that both selective androgen receptor modulators (SARMs) have their own unique advantages.

The choice between these two SARMs will ultimately depend on personal goals and preferences. MK-2866, also known as Ostarine or Enobosarm, is a milder option with minimal side effects, making it suitable for individuals focused on lean muscle mass and bone health. 

RAD-140, or Testolone, is potentially more potent in terms of muscle gains and is suitable for those seeking rapid muscle gain and increased workout endurance. It's the perfect to be used for bulking, and has less sude effects than traditional anabolic steroids. However, MK- 2866 is best for those looking to lose fat during both bulking and cutting cycles. 

However, it's essential to note that there is limited research on the long-term effects of these SARMs, and caution should be exercised when considering their usage. Additionally, pay close attention to your post cycle therapy (PCT) routine in order to ensure you build lean muscle mass the right way.

Always consult with a healthcare professional before starting any new supplement regimen to ensure your safety along your fitness journey.


Can I stack these two SARMs together for bodybuilding purposes?

Yes, you can stack them together. MK-2866 (Ostarine) and RAD-140 is a combination that is often used by bodybuilders for muscle gain. However, you should always consult a medical professional before starting any new supplement regimen in order to lean more about how these two SARMs work together. 

Which is safer - MK-2866 or RAD-140?

Both MK-2866 (Ostarine) and RAD-140 (Testolone) have their own safety profiles. However, a dosage of Ostarine is known to have fewer side effects, making it a safer choice for most individuals. That said, the safety of any supplement depends on factors like dosage, duration of use, and individual health status. Ostarine offers a more gentle approach to bodybuilding, whilst a dose of RAD 140 is more powerful for those wanting to improve their muscle mass more quickly. 

What is the best SARM for beginners?

MK-2866, also known as Ostarine, is generally considered a safer and more beginner-friendly option.It's less potent compared to RAD 140, making it a good starting point for those new to SARMs.

Which one is better, SARMs or steroids?

If you want to cut or bulk faster, and take your workout regimen to new heights, anabolic steroids may seem like a great choice. However, they come with a list of different side effects that have lead them to being illegal to purchase without a prescription, including extremely suppressed natural testosterone, heart attacks and liver toxicity. For this reason, SARMs are the better choice as you will not experience side effects that drastically impact your health. However, you will still get all the benefits of steroids, such as rapid muscle gains, fat loss and improved physical performance.

Which SARM is better for women?

RAD-140 is the stronger SARM, and is therefore more likely to have a more potent impact on women. MK-2866 is a mild SARM that is better suited to be used by female bodybuilders, and it has the added benefit of being great for cutting. 

Are these two SARMs available legally?

The legality of SARMs like MK-2866 (Ostarine) and RAD-140 (Testolone) varies by country. In the United States, they are currently legal to buy and sell for "research purposes". However, they are not approved by the FDA for medical use, and their sale as supplements for human consumption is illegal. Always check the laws in your area before purchasing.

How long is the recommended cycle for MK-2866 and RAD-140?

When it comes to how long you need to use each SARM, the recommended cycle is 6 to 8 weeks. Some users, when they want to bulk for longer, push their cycle to 10 weeks. It is always best to seek medical advice when it comes to SARMS, in order to decide which types of cycles will suit your individual lifestyle and health the best. This is the best way to experience less side effects, and avoid issues like hair loss. 

  1. Rosen, J, and A Negro-Vilar. “Novel, non-steroidal, selective androgen receptor modulators (SARMs) with anabolic activity in bone and muscle and improved safety profile.” Journal of musculoskeletal & neuronal interactions vol. 2,3 (2002): 222-4.
  2. Roch, Paul Jonathan et al. “Ostarine and Ligandrol Improve Muscle Tissue in an Ovariectomized Rat Model.” Frontiers in endocrinology vol. 11 556581. 17 Sep. 2020, doi:10.3389/fendo.2020.556581
  3. Jayaraman, Anusha et al. “Selective androgen receptor modulator RAD140 is neuroprotective in cultured neurons and kainate-lesioned male rats.” Endocrinology vol. 155,4 (2014): 1398-406. doi:10.1210/en.2013-1725
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