In the ever-evolving landscape of fitness and bodybuilding, RAD-140, commonly known as Testolone, is making waves for its potential to unlock new levels of performance and muscle growth. This selective androgen receptor modulator (SARM) has garnered attention for its ability to enhance strength, accelerate fat loss, and promote lean muscle mass without the harsh side effects typically associated with anabolic steroids. But what exactly makes RAD-140 a game-changer in the world of performance enhancement?

In this article, we'll delve deep into the multifaceted benefits of RAD-140, outline optimal dosing strategies, and explore how it works within the body to deliver remarkable results. Whether you’re a seasoned athlete or just starting your fitness journey, understanding RAD-140 could provide the edge you’ve been looking for. Join us as we unravel the secrets of this powerful compound and its potential to transform your training regimen.

What Is RAD-140 (Testolone / EP0062)?

RAD-140, also known as Testolone and more recently EP0062 (vosilasarm), is a selective androgen receptor modulator (SARM) that has garnered significant attention in both the clinical and athletic worlds. Unlike anabolic steroids, which affect multiple tissues and can result in widespread systemic effects, SARMs like RAD-140 are designed to selectively target androgen receptors in muscle and bone tissue, aiming to maximize anabolic effects while minimizing undesirable side effects on other organs.

Origins and Development

RAD-140 was initially developed by Radius Health, Inc. for potential androgen replacement therapy. In 2020, the compound was licensed to Ellipses Pharmaceuticals for its therapeutic application in hormone receptor-positive breast cancer, under the name EP0062/vosilasarm. Its original synthesis and preclinical profile were first described in 2011, demonstrating androgen receptor (AR) agonist activity, osteoblast differentiation, and neuroprotective effects in vitro Jayaraman et al., ACS Med Chem Lett, 2011.

Mechanism of Action

RAD-140 binds selectively to androgen receptors, functioning as a tissue-specific agonist in anabolic target areas such as skeletal muscle and bone, while showing minimal activity in reproductive tissues like the prostate. This tissue selectivity distinguishes SARMs from traditional anabolic steroids, which often produce significant androgenic side effects, including liver stress and cardiovascular strain Narayanan et al., Mol Cell Endocrinol, 2018.

Therapeutic and Research Applications

RAD-140 is currently classified as an investigational compound. SARMs are being explored for a wide range of medical conditions including:

• Cachexia (muscle wasting)
• Osteoporosis (bone density loss)
• Breast cancer (AR+ tumors)
• Benign prostatic hyperplasia
• Alzheimer’s disease
• Muscular dystrophy
• Stress urinary incontinence
• Erectile dysfunction

The goal behind SARMs is to overcome the pharmacological and pharmacokinetic limitations of traditional androgens like testosterone and dihydrotestosterone (DHT), which are associated with serious adverse effects including hepatotoxicity, cardiac hypertrophy, and hormonal suppression Basaria, JAMA, 2010.

Athletic Use and Performance Benefits

Although RAD-140 was developed with clinical objectives in mind, its anabolic potency and favorable safety profile quickly made it popular among bodybuilders and athletes. RAD-140 is known for one of the highest anabolic-to-androgenic ratios among SARMs, meaning it delivers substantial increases in lean muscle mass, strength, and recovery with minimal androgenic side effects. Users report rapid physical improvements without the estrogenic or DHT-related consequences often seen with anabolic steroid use.

How RAD-140 Works in the Body

RAD-140 (Testolone) is a selective androgen receptor modulator (SARM) that exerts its effects by targeting specific androgen receptors (ARs) in muscle and bone tissue. These receptors are responsible for responding to androgens—hormones like testosterone—that promote muscle growth, bone density, and male secondary sex characteristics. When RAD-140 binds to these receptors, it mimics the anabolic effects of natural androgens, resulting in enhanced muscle protein synthesis and increased lean mass.

Selective Tissue Targeting

Unlike anabolic steroids that activate androgen receptors systemically, RAD-140 displays tissue-selective action, focusing primarily on skeletal muscle and bone while minimizing interaction with tissues like the liver and prostate. This selective binding significantly reduces the likelihood of common steroid-related side effects such as hepatotoxicity, prostate enlargement, and hormonal imbalance Narayanan et al., Mol Cell Endocrinol, 2018.

Neuroprotective Properties

RAD-140 also exhibits promising neuroprotective effects. Preclinical studies have shown that RAD-140 can protect brain cells from oxidative stress and apoptosis (programmed cell death). In particular, RAD-140 was as effective as testosterone in preventing cell death caused by apoptotic insults. These protective effects are mediated through MAPK/ERK signaling pathways, with elevated phosphorylation of ERK and sensitivity to MAPK inhibition via U0126 confirming the mechanism Dubois et al., ACS Med Chem Lett, 2011.

This neuroprotective potential opens the door for future therapeutic applications in conditions like Alzheimer’s disease and age-related neurodegeneration, where testosterone therapy is typically avoided due to systemic risks. As testosterone levels decline with age, tissues such as the brain—which are androgen-sensitive—may suffer functional losses. Because RAD-140 avoids androgenic stimulation of reproductive tissues, it presents a safer alternative to traditional testosterone replacement therapy (TRT) in aging populations.

Clinical Progress and Preclinical Insights

RAD-140 is a relatively new compound, with Phase 1 clinical trials completed in 2020. These early-stage human studies evaluated the compound’s safety, efficacy, and dose tolerance to inform future therapeutic investigations. Preclinical data in animal models further supports RAD-140’s anabolic effects, with results showing potent agonist activity on muscle tissue like the levator ani, and partial antagonist activity on androgen-sensitive tissues such as the seminal vesicles and potentially the prostate.

Benefits of Using RAD-140 (Testolone)

RAD-140 (Testolone) is widely recognized for its potent anabolic effects, especially its ability to increase lean muscle mass, promote fat loss, improve recovery, and even show potential anti-cancer activity. These effects are supported by both preclinical data and early human studies, highlighting the compound's unique therapeutic and performance-enhancing potential.

Increases Lean Muscle Mass

Preclinical studies demonstrate that RAD-140 has a dose-dependent anabolic effect on muscle tissue without stimulating androgenic effects in reproductive organs. In animal models, RAD-140 increased muscle mass at doses as low as 0.1 mg/kg, while exhibiting minimal prostate stimulation even at much higher doses like 30 mg/kg Kannan et al., ACS Med Chem Lett, 2013. Compared to testosterone propionate (TP), RAD-140 demonstrated similar anabolic efficacy at 0.5 mg/kg, but required significantly higher doses to match TP’s androgenic activity in the prostate, underscoring its selective tissue-targeting advantage.

In just 28 days, a greater than 10% increase in muscle mass and body weight was observed at the 0.1 mg/kg dose, with similar results at 1.0 mg/kg. This rapid and significant hypertrophy makes RAD-140 an attractive option for individuals looking to build size and strength quickly.

Tumor Suppression and Breast Cancer Research

RAD-140 is also under investigation for its potential to suppress estrogen receptor-positive (ER+)/androgen receptor-positive (AR+) breast cancer tumors, including those resistant to standard treatments such as CDK4/6 inhibitors and endocrine therapy. In a Phase 1 clinical trial involving 21 postmenopausal women with ER+/HER2- metastatic breast cancer (mBC), RAD-140 was administered at doses of 50 mg, 100 mg, and 150 mg daily Ellipses Pharma, 2022.

The most frequently observed treatment-emergent adverse events (TEAEs) included elevated liver enzymes (AST: 59.1%, ALT: 45.5%), elevated bilirubin (27.3%), and symptoms such as vomiting, dehydration, decreased appetite, and weight loss. Mechanistically, RAD-140 activates AR and alters the genomic distribution of estrogen receptors, repressing cell cycle genes driven by estrogen while upregulating AR-target genes, including known tumor suppressors. Future Phase 2 trials are expected to refine patient selection and assess combination therapies alongside current standards of care.

Fat Loss and Body Recomposition

RAD-140 is also effective in enhancing fat metabolism. By increasing the body’s metabolic rate, it supports fat oxidation while preserving lean muscle mass, making it a highly effective compound for cutting cycles or recomposition phases. Unlike many thermogenic fat burners, RAD-140 does not rely on stimulants and instead works through hormone receptor modulation, offering a cleaner and more sustainable fat-loss effect.

Accelerated Recovery and Performance Enhancement

Recovery is a critical part of any serious training regimen. RAD-140 helps accelerate muscle repair and reduce inflammation, allowing athletes to train more frequently with less downtime. This shortened recovery window translates into faster strength gains, improved endurance, and a greater capacity to push through plateaus. The compound’s ability to improve muscle regeneration gives it a powerful advantage for both competitive athletes and recreational lifters aiming to optimize performance.

Summary

RAD-140 offers a broad spectrum of benefits, including substantial muscle hypertrophy, fat loss without muscle compromise, faster recovery, and promising anti-cancer properties through its selective androgen receptor activation. Its unique ability to deliver high anabolic activity with minimal androgenic side effects makes it one of the most attractive SARMs available for both therapeutic research and performance enhancement. Ongoing clinical studies will continue to explore its role in both oncology and musculoskeletal health.

Recommended Dosage for RAD-140 (Testolone)

Determining the appropriate dosage of RAD-140 (Testolone) is essential for maximizing muscle-building and performance-enhancing effects while reducing the risk of side effects. RAD-140 is known for its potent anabolic activity and high receptor selectivity, which means users can experience substantial benefits even at moderate doses.

Optimal Daily Dosage Range

Most users report effective results within the 10–30 mg per day range. Beginners are advised to start with 10 mg daily to assess tolerance, response, and side effect profile. For those with more experience or specific goals in mind, dosages up to 30 mg daily may be used, but should be approached cautiously as higher doses may increase side effect risks without a proportionate benefit Narayanan et al., Mol Cell Endocrinol, 2018.

Recommended Cycle Length

A typical RAD-140 cycle runs between 8 to 12 weeks, after which users should undergo post-cycle therapy (PCT) to help restore natural testosterone production and endocrine balance. While RAD-140 is a selective androgen receptor modulator and does not convert to estrogen, it can still suppress endogenous testosterone depending on dose and cycle length. PCT agents such as Clomid (Clomiphene) or Nolvadex (Tamoxifen) are commonly used to assist recovery.

Daily Timing and Consistency

RAD-140 has a relatively long half-life of approximately 16–20 hours, which supports once-daily dosing. For best results, it is recommended to take the full dose at the same time each day, helping maintain consistent blood plasma levels and ensuring stable performance throughout the cycle US Patent 20060122296.

Stacking, Training, and Diet Considerations

RAD-140 may be used as a standalone compound or stacked with other SARMs like MK-677 (Ibutamoren) or LGD-4033 for enhanced anabolic synergy. However, stacking should only be done by experienced users who understand potential compound interactions and have a plan for managing combined suppression effects. Pairing RAD-140 with a structured resistance training program, a high-protein diet, and proper recovery will further amplify results in muscle gain, fat loss, and overall athletic performance.

Potential Side Effects of RAD-140 (Testolone / EP0062)

While RAD-140 (Testolone) is considered one of the safer and more selective anabolic agents in the SARM category, it is not without potential side effects. Clinical and preclinical studies, along with anecdotal user experiences, reveal several physiological impacts, especially at higher or prolonged dosages.

Clinical Safety and Tolerability

According to preclinical and Phase 1 clinical data, RAD-140 has been shown to be well tolerated up to 150 mg/day over 24 weeks Ellipses Pharma, 2022. This extended evaluation is longer than what exists for most SARMs. Pharmacokinetic analysis from these trials indicates that RAD-140 has a terminal half-life of approximately 44 hours, with complete oral bioavailability and rapid absorption Goyagi et al., J Clin Oncol, 2020.

Hormonal Suppression and Endocrine Effects

RAD-140 has been shown to suppress luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone via the hypothalamic-pituitary-gonadal (HPG) axis, especially in a dose-dependent manner Narayanan et al., Mol Cell Endocrinol, 2018. This suppression may lead to imbalances between testosterone and estrogen, resulting in symptoms such as:

• Acne
• Low libido
• Lethargy
• Gynecomastia
• Depressed mood
• High blood pressure
• Testicular atrophy

Despite the fact that RAD-140 does not aromatize into estrogen, hormonal imbalance can still cause estrogen-related side effects indirectly. Incorporating a proper post-cycle therapy (PCT) after use is essential to help restore natural hormone production and minimize the risk of long-term endocrine disruption.

Cardiovascular and Lipid Profile Impacts

RAD-140, like other SARMs, has been associated with reductions in high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides, again in a dose-dependent manner. These changes resemble those seen with traditional anabolic steroids and may present cardiovascular risks if not monitored appropriately Basaria et al., JAMA, 2010.

Liver Toxicity and Enzyme Elevation

Liver enzyme elevation is a well-documented concern with oral anabolic compounds. In RAD-140's case, ALT and AST levels have been shown to rise in Phase 1 trials at doses between 50–150 mg/day. However, animal studies using doses as high as 10 times the effective range (e.g., 30 mg/kg) showed no hepatotoxicity and no transaminase elevation greater than 2x baseline Kannan et al., ACS Med Chem Lett, 2013. While the therapeutic range appears safe, supratherapeutic doses or prolonged use may still carry some hepatic risk. Regular liver function testing (LFTs) is advised throughout any cycle.

Commonly Reported Side Effects

User-reported and clinical side effects for RAD-140 and other SARMs include:

• Headaches
• Nausea
• Mood swings
• Dry mouth
• Constipation
• Indigestion
• Upper respiratory infections (URIs)

Most of these symptoms are considered mild to moderate and often subside with dose adjustment or inter-cycle breaks. Individual tolerance, hydration, and general health can influence the severity and frequency of these reactions.

Managing Risk: PCT and Monitoring

Due to the compound’s strong androgenic activity, it is highly recommended to implement post-cycle therapy immediately after discontinuing use. PCT agents like Clomid (Clomiphene citrate) or Nolvadex (Tamoxifen) help reignite endogenous testosterone production, reduce estrogen-related side effects, and prevent long-term hormonal suppression.

Routine bloodwork, including hormone panels, lipid profiles, and liver function tests, should be conducted before, during, and after a cycle to detect any deviations from baseline and guide dosage adjustments or supplementation.

RAD-140 vs. Traditional Anabolic Steroids

RAD-140 (Testolone) offers a modern alternative to traditional anabolic steroids, with several key distinctions in terms of safety, selectivity, and user experience.

Tissue Selectivity and Androgen Targeting

One of RAD-140's primary advantages is its selective action on androgen receptors in muscle and bone tissue, whereas anabolic steroids bind non-selectively across various organ systems. This selectivity reduces the likelihood of unwanted effects on the prostate, liver, and skin while maintaining strong anabolic outcomes Narayanan et al., Mol Cell Endocrinol, 2018.

Side Effect Profile

While both RAD-140 and steroids can suppress natural testosterone production, RAD-140 is associated with less severe suppression and a lower incidence of estrogen-related side effects such as gynecomastia and mood instability. Additionally, RAD-140 is not aromatized into estrogen and has shown a reduced risk of liver and cardiovascular toxicity at therapeutic dosages Basaria et al., JAMA, 2010.

Oral vs. Injectable Use

Another practical benefit of RAD-140 is its oral administration, which makes it more user-friendly compared to injectable steroids. This route eliminates the risk of injection-site infections, abscesses, and needle-related complications, offering a more accessible option for performance enhancement.

Best Practices for Cycling RAD-140

Cycle Duration and Dosage

A typical RAD-140 cycle lasts 8 to 12 weeks, followed by a post-cycle therapy (PCT) protocol. Beginners are encouraged to start at 10 mg/day, increasing gradually based on tolerance and individual response. Maintaining this progressive approach helps mitigate side effects while maximizing results.

Training and Nutrition

For optimal effectiveness, RAD-140 should be paired with a structured resistance training program, regular cardiovascular exercise, and a nutrient-dense diet. Emphasizing protein intake, healthy fats, and complex carbs will support muscle growth, fat loss, and overall recovery. Proper hydration and sleep are also critical for maximizing gains and maintaining hormonal balance.

Post-Cycle Therapy (PCT)

PCT is essential for recovering natural testosterone levels following a RAD-140 cycle. Common agents include Clomid (Clomiphene) and Nolvadex (Tamoxifen), which stimulate LH and FSH production through the hypothalamic-pituitary-gonadal axis. PCT typically lasts 4–6 weeks, depending on the severity of suppression. Monitoring hormone levels with blood work ensures a successful recovery and minimizes the risk of long-term side effects.

Legal Status and Regulations Surrounding RAD-140

Research Chemical Classification

RAD-140 is currently not approved by the U.S. FDA for medical use and is classified as a research chemical, legally purchasable for research purposes only. It is not approved for human consumption, yet remains widely available online through unregulated sources. Users should be aware of the legal risks and quality control issues associated with these channels.

Controlled Substance Implications

Though not scheduled under the U.S. Controlled Substances Act, RAD-140 may still be regulated at the state or federal level, and enforcement can vary. Countries outside the U.S. may impose stricter classifications or outright bans. Understanding your local legal framework is crucial before purchasing or using RAD-140.

Anti-Doping Rules and WADA Ban

The World Anti-Doping Agency (WADA) classifies RAD-140 and all SARMs as prohibited substances in-competition and out-of-competition under Section S1 of the Prohibited List WADA Prohibited List, 2024. Athletes in professional or amateur sports governed by WADA-compliant organizations must avoid RAD-140 or risk disqualification, suspension, and career-ending penalties.

Conclusion: Is RAD-140 Right for You?

Determining whether RAD-140 is the right choice for you depends on your individual goals, experience level, and tolerance for potential risks. For those seeking significant muscle growth, enhanced strength, and improved fat loss, RAD-140 offers a compelling alternative to traditional anabolic steroids. Its selective action on androgen receptors, coupled with its relatively lower risk of side effects, makes it an attractive option for many athletes and bodybuilders.

However, it is important to approach RAD-140 with caution and thorough research. Understanding the proper dosing protocols, potential side effects, and legal implications is essential for making an informed decision. Consulting with a healthcare professional or experienced coach can provide valuable insights and help to develop a safe and effective plan for incorporating RAD-140 into your training regimen.

Ultimately, the decision to use RAD-140 should be based on a careful assessment of the benefits and risks, as well as a commitment to responsible use. By following best practices for cycling, monitoring the body's response, and adhering to legal regulations, users can unlock the power of RAD-140 to achieve their fitness goals safely and effectively. Whether you are a seasoned athlete or just starting your fitness journey, RAD-140 has the potential to transform your training and help you reach new heights in performance and physique.