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RAD140 (Testolone): Uses, Side Effects & Danger

Written by Mathew Eng, PharmD | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Mathew Eng, PharmD | Last updated:
Man with muscles

Testolone is an unapproved drug that comes with a ton of warnings. Why do people use it? Learn about the risks and dangers of RAD140.

Disclaimer: While testolone is not illegal to have, it is illegal to sell and banned in professional and amateur league sports. 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.

Testolone is an unsafe experimental drug not approved for human consumption. Do not take it under any circumstances.

What is RAD140 (Testolone)?


RAD140, also known as testolone, is a new investigational drug which has become popular among bodybuilders, who claim that it has muscle-building effects. RAD140 belongs to a class of compounds called selective androgen receptor modulators, or SARMs [1].

SARMs bind 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 tend to have similar effects because they work on the same receptor. The intended targets of SARMs include the muscles, bones, and liver [2].

SARMs are of particular interest to researchers because they are selective about where they work. They mostly target muscle and bone tissues, and appear to have minimal effects on the prostate and other organs. Because of this, some researchers believe that SARMs could potentially treat hormone-related or muscle-wasting disorders with fewer side effects than existing treatments, but this is an unproven hypothesis without data to back it up [2].

This potential has also made SARMs a popular choice over testosterone or steroids for bodybuilders. 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 some believe could potentially reduce its side effects compared to testosterone or other steroids. No data backs up this hypothesis.



  • May increase muscle mass
  • May increase fat-burning
  • May protect brain cells
  • 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
  • Safety profile and full side effects are unknown
  • Appropriate dosage are unknown

Use in Bodybuilding

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, without research to back it up.

In fact, without complete studies, testosterone replacement therapy remains a safer approach than using SARMs like testolone. Remember that we know nothing about the safety profile of this experimental, unapproved drug, while testosterone’s effects are well-studied and predictable.

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

Some athletes believe RAD140 can boost testosterone, muscle mass, and physical performance. It is banned in professional sports, and without more clinical studies, we don’t know whether it works or how safe it might be.

Mechanism of Action

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

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

The selective ability of SARMs is not fully understood yet. According to some researchers, they may target and selectively activate different proteins than testosterone. This results in only certain androgen receptors – mainly in the muscles – being activated [2].

The chemical structure of RAD140 is very different from the structure of steroid hormones like testosterone. Thus, the pathways that convert testosterone into other hormones (like estrogen) cannot act on testolone [1].

Based on a study in rats, some researchers have suggested that RAD140 could activate receptors in injured regions of the brain. In the brains of rats given RAD140, MAPK activity increased, thus protecting neurons from damage [5].

RAD140 activates androgen receptors in muscles, but not in most other tissues. Some researchers believe that this reduces testolone’s potential to produce side effects (compared to testosterone or other steroids), but more research is needed.

RAD140 (Testolone) vs. Ostarine

Ostarine, also known as Enobosarm, is a popular SARM that has undergone limited testing in humans. One clinical trial has investigated ostarine’s ability to prevent the drastic weight loss (cachexia) caused by severe illnesses [7].

RAD140 and ostarine are both SARMs; some researchers have found minimal effects on the prostate and reproductive organs, but without high-quality clinical studies, we can’t know if this is truly the case [8].

Anecdotal Reports

The claims below are strictly anecdotal and have not been investigated in any relevant studies.

Anecdotally, testolone and ostarine differ when it comes to their effects on muscle and fat. According to anecdotal reports from people who use SARMs, 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, many of these same anecdotes report that RAD140 is a stronger SARM that provides better muscle growth. It’s a more popular choice for bulking.

Remember that none of these anecdotes have ever been tested in clinical research, and they should all be taken with several large grains of salt. People’s reports of their own experience can be interesting, but they cannot replace high-quality, placebo-controlled studies conducted by experts in the field.

Potential Uses of RAD140

1) Increasing Muscle Mass

RAD140 is popular in the bodybuilding community for its purported muscle-building effects. Some researchers believe that, 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 animal study that examined RAD140’s effect on muscle growth. In the study, researchers tested different doses in 9 monkeys. They found that monkeys that received RAD140 daily had increased lean muscle mass after 28 days [1].

Human studies of RAD140 have not yet been performed.

RAD140 is popular in bodybuilding, but no clinical trials have examined its safety and efficacy in humans.

2) Breast Cancer

Researchers are currently investigating RAD140 for potential action against 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 [9].

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].

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].

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.

Users claim RAD140 improves sleep and sexual performance, but no studies back this up.

4) Weight Loss

Some people believe that SARMs 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].

The study did find that RAD140 improves cholesterol levels. Additionally, a higher muscle mass can increase energy use to further promote fat loss, but these factors did not play out to lower body fat in the single available study. Thus, there is currently no evidence that testolone promotes weight loss [1, 10].

Some people believe SARMs increase muscle mass and reduce body fat, but the limited studies available don’t support this use.

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. Testolone is an unapproved drug with very limited evidence of safety or efficacy: that is, we dont know how safe it is, or even whether it works.

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, 11].

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 [12].

In addition, 39% of products contained an unapproved drug and 25% contained substances not listed on the label [12].

Human studies haven’t verified the safety and efficacy of RAD140. It’s banned in professional sports and most products available online are dangerous. For this reason, we strongly recommend against taking this drug.

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, its proponents say that RAD140 should cause fewer unwanted effects than testosterone, but this is completely unproven. RAD140 still has the potential to cause testosterone-related side effects. These may include [13, 14]:

  • 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 online claims, 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. It may slightly raise blood estradiol, similar to other SARMs. Some people claim that RAD140 is special as it won’t aromatize to estrogen or shut down your testosterone, but no studies back up these claims. Plus, 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.

There is currently no way of knowing all the potential side effects of testolone because of the lack of clinical studies. This is only one of the many reasons we strongly recommend against taking RAD140.

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 [15].

The selective nature of SARMs means that they should have little to no effect on the prostate. Based on current research, RAD140 does not seem to increase the size of the prostate. However, research has not been done in humans yet, and many users have reported experiences that contradict the supposed selective benefits of testolone. Full scale clinical studies could very well find adverse effects on the prostate [1, 5].

RAD140 Dosage & Supplements


There is no set dose for RAD140, as it hasnt been investigated in humans. Until and unless clinical studies sufficiently explore this drug, in context and for a specific purpose, a safe dosage does not exist.

Bodybuilding resources usually recommend a dosage of 10 to 30 mg per day for men and 5 to 10 mg per day for women.

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.

These doses are purely speculative and not backed up by scientific research.

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). No scientific research backs up these doses.


In order to increase results, bodybuilders will sometimes combine RAD140 with other SARMs or steroids. Users have reported “stacking” with ostarine, ibutamoren, and conventional steroids like Primobolan. The combination with ostarine is reported to improve recovery. For cutting or endurance gains, it’s usually stacked with cardarine.

We cannot stress this enough: these stacks are very dangerous. Each of these drugs is unapproved and insufficiently studied. None of them have complete safety profiles. We strongly recommend against taking any single one of these substances, let alone two or three at once.

Post-Cycle Therapy

The use of SARMs and steroids can suppress the body’s ability to produce testosterone. Most experienced users recommend post-cycle therapy (PCT) after each cycle of RAD140 [14].

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. However, without real clinical studies, there is no safe way of taking these substances.


Many online users believe that this compound is a safer alternative to testosterone replacement therapy. They cite anecdotal reports and theories that have no supporting data or studies of any kind to investigate them.

Based on anecdotal reports of adverse side effects, the lack of clinical studies, and the dearth of available data, we believe that testosterone replacement therapy – under the supervision of a licensed physician – remains a much safer alternative to taking this, or any, SARM.

Related Genetics

Patients with hormonal imbalances or deficiencies should approach the use of RAD140 with caution [16].

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 [16, 17].

User Reviews

As an unapproved drug used as a supplement by bodybuilders, people say they think that RAD140 is great for increasing muscle mass while also reducing body fat. Some believe 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.

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


RAD140 is an investigational drug popular for its muscle-building action. It is a SARM that may increase muscle mass. Research is currently exploring RAD140’s effects on health, as its safety, efficacy, side effects, and long-term risks 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. Based on the available evidence, a lack of human studies demonstrating safety and efficacy, and anecdotal reports of adverse effects, we do not recommend using testolone. Physician-supervised testosterone replacement therapy is a better approach than untested SARMs.

About the Author

Mathew Eng

Mathew Eng

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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