Testolone is primarily used to build muscle, but new studies show promise for breast cancer suppression and muscle wasting diseases. Learn about uses & risks of RAD140.

Disclaimer: By writing this post, we are not recommending this drug. Some of our readers who were already taking the drug requested that we commission a post on it, and we are simply providing information that is available in the clinical and scientific literature.

What is RAD140 (Testolone)?


RAD140, also known as Testolone, is a new investigational drug popular for its muscle-building effects.

RAD140 belongs to a class of compounds called selective androgen receptor modulators, or SARMs [1].

SARMs work by binding to androgen receptors that are found in different areas of the body. Normally these receptors interact with androgens, which are a group of steroid hormones. Androgens like testosterone, dihydrotestosterone, and androstenedione are naturally produced by the body [2].

SARMs and testosterone have similar effects because they work on the same receptor. Some of these effects include influencing the muscles, bones, and the liver [2].

The advantage of SARMs is that they are selective about where they work. They mostly target muscle and bone tissues while having minimal effects on other organs. This allows SARMs to potentially treat hormone-related or muscle-wasting disorders with fewer side effects [2].

This has also made SARMs a popular choice over testosterone or steroids for bodybuilding. Although testosterone and steroids boost muscle growth, they also have unwanted effects on the prostate and reproductive organs, among others [3].

RAD140 (Testolone) is a SARM: it mimics testosterone but mostly targets the muscles, which may reduce its side effects.



  • Increases muscle mass
  • May increase fat-burning
  • May protect brain cells
  • Fewer side effects compared to steroids
  • May be beneficial for certain breast cancers


  • May suppress testosterone
  • May cause hair loss, fatigue, and mood swings
  • No human studies
  • Long-term risks are unknown

From Bodybuilding to Cancer Prevention

RAD140 has become popular in men with low testosterone levels who want to avoid testosterone replacement therapy but are looking to maintain their physical and sexual performance. Such use is still completely anecdotal.

Research is currently investigating the potential role of RAD140 in increasing muscle mass, fighting breast cancer, and protecting cells in the brain [1, 4, 5].

Despite the lack of safety research in humans, bodybuilders use RAD140 to increase strength and endurance.

RAD140 is not illegal, but it is banned in professional sports. Along with all other SARMs, RAD140 is on the prohibited list of the World Anti-Doping Agency [6].

RAD140 is not well researched in humans, though people use it to boost testosterone, muscle mass, and physical performance.

Mechanism of Action

RAD140 works by selectively stimulating androgen receptors in the body. It targets receptors in the muscle and bone and has little to no effect on the reproductive organs [1].

The selective ability of SARMs is not fully understood yet. They most likely work by selectively activating different proteins than testosterone. This results in only certain androgen receptors–mainly in the muscles–being activated [2].

The structure of RAD140 is very different from the structure of steroid hormones like testosterone. This means the body isn’t able to convert RAD140 into other hormones like estrogen that may have undesirable effects [1].

This compound stimulates muscle growth by promoting the development of muscle cells and proteins [2].

Based on a study in rats, RAD140 activates receptors in regions of the brain that are injured. This triggers a signal called the MAPK pathway that helps protect cells [5].

RAD140 activates androgen receptors in muscles. It spares reproductive organs and can’t be converted to steroid hormones, which lowers the risk of side effects.

RAD140 (Testolone) vs. Ostarine

Ostarine, also known as Enobosarm, is a popular SARM that has been tested in humans. One clinical trial has looked at Ostarine’s ability to improve drastic weight loss (cachexia) caused by severe illnesses [7].

RAD140 and Ostarine are both SARMs, so they should have minimal effects on the prostate and reproductive organs [8].

The two differ when it comes to their effects on muscle and fat. Based on anecdotal reports, Ostarine has milder muscle-building effects and is better for fat loss. It’s the usual choice for cutting cycles and for those that want to gain modest but lean muscle mass.

On the other hand, RAD140 appears to be a stronger SARM that provides better muscle growth. It’s a more popular choice for bulking.

RAD140 and Ostarine are SARMs with similar actions. Anecdotally, Ostarine is better for fat loss while RAD140 has stronger muscle-building effects. No studies have confirmed this.

Potential Uses of RAD140

1) Increasing Muscle Mass

RAD140 is popular in the bodybuilding community for its muscle-building effects. Much like other SARMs, it may increase muscle growth without the unwanted effects of conventional steroids [2].

Despite this popularity, the scientific evidence behind RAD140 is scant.

Currently, there is only one pilot study that examined RAD140’s effect on muscle growth. In the study, researchers tested different doses in 9 monkeys. They found that RAD140 increases lean muscle mass after 28 days of use [1].

Human studies of RAD140 have not been performed yet. However, a clinical trial of a different SARM called Ostarine found that it improves lean muscle mass and physical function in the elderly [9].

RAD140 is popular in bodybuilding for its muscle-building effects, but no clinical trials have examined its safety and efficacy.

2) Breast Cancer

RAD140 is showing promising results for breast cancer [4].

A common form of breast cancer called androgen and estrogen receptor-positive (AR/ER+) is sensitive to hormones. Medications that affect these receptors, like SARMs, may have cancer-fighting potential [10].

In a cell study, RAD140 stopped the growth of AR/ER+ breast cancer by blocking the effects of estrogen [4].

Specifically, RAD140 appears to suppress the ESR1 gene. This gene is responsible for creating estrogen receptors. Without sufficient receptors, estrogen becomes inactive [4].

According to cell studies, RAD140 may shrink androgen and estrogen receptor-positive breast cancer.

3) Brain Effects

Androgens play an important role in protecting the brain. They can increase brain cell growth, improve memory, and decrease amyloid-beta accumulation. Amyloid-beta plaques are among the main causes of Alzheimer’s disease [5].

In a rat study, RAD140 protected brain nerves against injury from amyloid-beta plaques. Additionally, RAD140 and testosterone were equally effective at protecting against neurotoxins [5].

Interestingly, some RAD140 users report better sleep, but there are no studies to back this effect up. Same goes for its supposed ability to enhance sexual performance–although this could be tied to its testosterone-mimicking effects.

RAD140 may protect the brain against amyloid-beta plaques that cause Alzheimer’s disease. Users claim it improves sleep and sexual performance, but no studies back this up.

4) Weight Loss

SARMs are known to increase muscle mass and reduce body fat.

Only one study in monkeys looked at RAD140’s effects on muscle and fat. Although it increased lean muscle, the effect on body fat was unclear [1].

However, the study did find that RAD140 improves cholesterol levels. Additionally, a higher muscle mass can increase energy use to further promote fat loss [1, 11].

According to limited evidence, RAD140 might support weight loss by improving cholesterol levels and increasing muscle mass.

Limitations and Caveats

Limited Research

RAD140 benefits have yet to be explored in human studies. This drug has only been tested in rats and monkeys. Although it is used as a supplement by athletes, the long-term benefits and risks of human use are unknown.

Prohibited Substance

RAD140, just like all other SARMs, is banned in professional sports by the World Anti-Doping Agency. Researchers have already developed methods to detect RAD140 in drug tests [6, 12].

Product Quality

SARM users should be careful when purchasing products online.

In a recent study, researchers analyzed 44 different SARM products that were sold online. They found that only 52% actually contained SARMs [13].

In addition, 39% of products contained an unapproved drug and 25% contained substances not listed on the label [13].

Human studies haven’t verified the safety and efficacy of RAD140. It’s banned in professional sports and most products available online are dangerous.

RAD140 Side Effects and Risks


RAD140 is a new investigational substance. Its safety and side effects have not been clinically evaluated yet.

Based on how SARMs work, RAD140 should cause fewer unwanted effects than testosterone. That said, RAD140 still has the potential to cause testosterone-related side effects. These may include [14, 15]:

  • Breast tenderness/growth in men
  • Abnormal body hair growth in women
  • Changes in sex drive
  • Male pattern baldness/hair loss
  • Mood swings and anxiety/depression
  • Nausea and vomiting

Bodybuilders commonly report hair loss as a side effect, which is reversed once they stop taking RAD140.

Clinical trials haven’t tested the safety of RAD140 yet. Despite the improved selectivity, it may still cause hair loss and breast growth in men, changes in sex drive, and mood disorders.

Testosterone Suppression & Estrogen Effects

SARMs can suppress the body’s natural testosterone production. And although it shouldn’t cause a full-blown hormonal imbalance, it may slightly raise blood estradiol–similar to other SARMs. Some claim that RAD140 is special as it won’t aromatize to estrogen or shut down your testosterone, but user reviews suggest otherwise.

In theory and in practice, RAD140 can potentially cause testosterone suppression and estrogen buildup. This can cause decreased sex drive, depression, and tiredness. Users recommend PCT (Clomid or Nolvadex) to restore hormone levels – which goes to say it’s probably not as selective as some advocates claim.

The degree of suppression or estrogen-like effects can vary–some users report being more sensitive to it, while it doesn’t impact others as much. Greater doses and longer use of any substances will always increase your risk of unwanted effects, and RAD140 is no exception.

RAD140 may suppress testosterone and increase estrogen, leading to reduced sex drive, depression, and fatigue. Long-term use of higher doses increases your risk of side effects.

Prostate Risks

One of the biggest drawbacks of using testosterone is the negative effects it has on the prostate. Testosterone enlarges the prostate and potentially increase the risk of prostate cancer [16].

The selective nature of SARMs means that they should have little to no effect on the prostate. Based on current research, RAD140 does not increase the size of the prostate. However, research has not been done in humans yet [1, 5].

RAD140 Dosage & Supplements


There is no set dose for RAD140, as it hasn’t been investigated in humans.

Bodybuilding resources usually recommend a dosage of 10 to 30 mg per day.

For women, a dosage of 5 to 10 mg per day is recommended.

Users typically cycle RAD140 for 8 to 12 weeks. The off-cycle can vary: some recommend they last as long as the cycles, while others think that a shorter off-cycle of 6-8 weeks is sufficient.

Veterans will tailor these depending on their labs, checking to see how the cycles affected their liver markers and hormone balance.

RAD140 appears to have good bioavailability. According to research in monkeys, about 70% of the drug is absorbed into the body when ingested [1].

Due to the lack of clinical trials, there’s no established RAD140 dosage. Bodybuilders usually cycle it over 8-12 weeks at 10-30 mg/day (5-10 /day for women).


In order to increase results, bodybuilders will sometimes combine RAD140 with other SARMs or steroids. Users have reported stacking with Ostarine, Ibutamoren, and with conventional steroids like Primobolan. The combo with Ostarine is reported to improve recovery. For cutting or endurance gains, it’s usually stacked with Cardarine.

Post-Cycle Therapy

The use of SARMs and steroids can suppress the body’s ability to produce testosterone. The extent of testosterone suppression usually varies between each person and also depends on the dose and duration of use. However, most experienced users recommend post-cycle therapy (PCT) after each cycle of RAD140 [15].

PCT usually involves taking Nolvadex and Clomid to restore hormone levels. The optimal length of PCT can vary depending on the length of SARM use. Users typically report taking PCT for 3 to 4 weeks.

Users often stack RAD140 with other SARMs or steroids. Most of them recommend PCT with Nolvadex and Clomid for 3 to 4 weeks after each cycle.


There are vendors who sell RAD140 in the United States. You can get 10% off by using the code “selfhacked”.

We at SelfHacked advise speaking to a doctor before taking any drug, especially an unscheduled drug with limited long-term safety data in humans.

Additional RAD140 (Testolone) Resources

Related Genetics

Patients with hormonal imbalances or deficiencies should approach the use of RAD140 with caution [17].

Mutations in the gene coding for the androgen receptor may change the body’s response to RAD140. Depending on the mutation, RAD140 can have increased or decreased activity in the body. People with variations in this gene may also be susceptible to more side effects with RAD140. However, this has yet to be researched in more detail [17, 18].

User Reviews

As a bodybuilding supplement, people have found that RAD140 is great for increasing muscle mass while also reducing body fat. According to some, it also improves speed, stamina, and endurance during exercise.

Users also report that RAD140 works quickly, with evident results in as little as 3 to 4 weeks.

RAD140 tends to cause testosterone suppression and most users opt-in for PCT after.

Side effects reported by users include hair loss, tiredness, and decreased sex drive. Others have experienced mood changes and joint pain. A few users who do lab tests after cycles had high liver markers (ALT and AST) after taking RAD140. It’s unknown what other substances they were using.


RAD140 is an investigational drug popular for its muscle-building action. It is a SARM that increases muscle mass to a similar extent as testosterone but without many of the unwanted effects. Research is currently exploring RAD140’s effects on muscle mass, breast cancer, and brain health.

However, the safety and long-term risks of RAD140 in humans are unknown.

Side effects commonly reported by users include temporary hair loss, decreased sex drive, and mood changes. Like all SARMs, RAD140 is banned (and actively screened for) in professional sports.

Users should also be cautious when purchasing SARMs online; many products do not contain the advertised ingredients. 

About the Author

Mathew Eng, PharmD


Mathew received his PharmD from the University of Hawaii and an undergraduate degree in Biology from the University of Washington.

Mathew is a licensed pharmacist with clinical experience in oncology, infectious disease, and diabetes management. He has a passion for personalized patient care and believes that education is essential to living a healthy life. His goal is to motivate individuals to find ways to manage their chronic conditions.

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