Testolone RAD-140

Product Overview

Testolone (RAD-140) 15 mg by Zyvex Pharmaceuticals contains 15 mg of Testolone per tablet and is supplied in packs of 100 tablets. RAD-140, also known as Testolone and Vosilasarm, is an orally active, non-steroidal Selective Androgen Receptor Modulator (SARM) developed to activate androgen receptors while attempting to achieve a more tissue-selective pharmacological profile than conventional anabolic-androgenic steroids.

RAD-140 is chemically distinct from Testosterone, Trenbolone, Oxandrolone, and other steroidal androgens, but it still acts through the androgen receptor (AR). This means its non-steroidal structure does not eliminate anabolic, androgenic, endocrine, hepatic, or metabolic effects.

RAD-140 has undergone limited human clinical evaluation. A first-in-human Phase 1 study evaluated RAD-140 as an androgen-receptor-targeted agent in postmenopausal women with estrogen-receptor-positive, HER2-negative metastatic breast cancer. The study confirmed human androgen-receptor engagement but also reported frequent liver-enzyme abnormalities and other adverse events. RAD-140 has not become an FDA-approved medicine for bodybuilding, muscle growth, hormone replacement, or routine cancer therapy.

FDA continues to identify products marketed as RAD-140/Testolone for human use as unapproved new drugs. The 15 mg tablet strength should therefore be interpreted as stated product content rather than an approved therapeutic or athletic-performance dose.

Product Class

• Selective Androgen Receptor Modulator (SARM)
• Non-steroidal androgen receptor agonist
• Investigational anabolic agent
• Orally active androgen-receptor modulator
• Experimental oncology research compound
• Muscle and bone research compound
• Non-testosterone synthetic androgen-receptor ligand

Indications

Clinical and Research Context

RAD-140 was developed as a tissue-selective androgen-receptor modulator and has been investigated for potential applications involving androgen-responsive tissues.

Research interest has included:

• Androgen-receptor-positive cancer biology
• Muscle-wasting conditions
• Lean-tissue preservation
• Bone-related anabolic signaling
• Age-related loss of muscle
• Androgen-receptor pharmacology

The most important published human study to date involved women with advanced ER-positive/HER2-negative breast cancer. RAD-140 demonstrated pharmacological androgen-receptor activity, but this small Phase 1 oncology trial does not establish RAD-140 as a broadly approved or safe medicine.

Performance Context

In bodybuilding and physique communities, Testolone is commonly discussed in relation to:

• Lean-mass development
• Strength-related goals
• Muscle retention during calorie restriction
• Body recomposition
• Training recovery
• Androgen-receptor-mediated anabolic effects

These are non-approved applications. Claims that RAD-140 can provide steroid-like muscle growth without steroid-like adverse effects are not supported by adequate long-term human evidence.

FDA has specifically challenged marketing claims that RAD-140 can stimulate major muscle growth, improve strength, or provide anabolic benefits with reduced toxicity, classifying marketed RAD-140 products as unapproved drugs.

Mechanism of Action

RAD-140 binds to the androgen receptor, a nuclear receptor involved in regulation of skeletal muscle, bone, reproductive tissues, and many other physiological systems.

Following receptor binding, the activated androgen-receptor complex can alter transcription of androgen-responsive genes. This provides the biological basis for its anabolic effects in experimental models.

Potential androgen-receptor-mediated actions include:

• Muscle protein-related signaling
• Changes in nitrogen balance
• Lean-tissue anabolic signaling
• Bone-related androgen activity
• Changes in body composition
• Suppression of hypothalamic-pituitary-gonadal signaling

Unlike Testosterone, RAD-140 is not a physiological precursor for DHT or estradiol. It is not conventionally aromatized to estrogen and is not converted to DHT through 5-alpha-reductase.

However, androgen-receptor activation can still produce negative endocrine feedback. Consequently, RAD-140 may suppress endogenous testosterone and gonadotropin signaling even though it does not directly convert to estrogen.

Potential Benefits

The potential benefits attributed to RAD-140 are primarily based on its androgen-receptor activity and experimental anabolic effects.

Research and non-medical interest include:

• Lean-body-mass support
• Muscle-tissue preservation
• Androgen-receptor-mediated anabolic signaling
• Potential strength-related effects
• Bone-related anabolic activity
• Body-composition changes

RAD-140 has often been described as having a favorable anabolic-to-androgenic profile in experimental systems. Such selectivity should not be interpreted as proof of safety in humans.

Human data remain limited. In the published Phase 1 oncology study, common treatment-emergent adverse events included elevations in AST, ALT, and bilirubin, as well as vomiting, dehydration, decreased appetite, and weight loss. The trial also demonstrated clear androgen-receptor engagement in patients.

These findings reinforce an important distinction: RAD-140 is pharmacologically active in humans, but evidence of receptor activity does not demonstrate a favorable long-term risk-benefit profile for healthy users.

Synergy & Stacking

RAD-140 is commonly discussed with other SARMs, anabolic compounds, and growth-related agents. These combinations are not validated clinical protocols.

• Ligandrol / LGD-4033: Another investigational SARM. Combining both increases cumulative androgen-receptor stimulation and may increase endocrine suppression.
• Ostarine / MK-2866: An investigational SARM with overlapping androgen-receptor pharmacology.
• MK-677 / Ibutamoren: A growth-hormone secretagogue acting through the ghrelin receptor rather than the androgen receptor.
• Testosterone: A physiological steroid hormone and established TRT agent that also activates androgen receptors but has broader endocrine physiology.
• Growth Hormone: Acts primarily through the GH/IGF-1 axis and is pharmacologically distinct from RAD-140.

Combining several SARMs does not increase tissue selectivity. Instead, it may increase overall androgenic exposure, endogenous testosterone suppression, lipid disturbances, hepatic stress, and uncertainty regarding adverse effects.

Likewise, adding Testosterone does not convert RAD-140 use into legitimate TRT or make an investigational SARM medically supervised by default.

HRT/TRT Application

Testolone is not Testosterone Replacement Therapy.

Although both RAD-140 and Testosterone activate androgen receptors, Testosterone is a naturally occurring steroid hormone that also serves as a precursor to DHT and estradiol. These metabolites are important for bone, sexual function, reproductive physiology, mood, and other endocrine functions.

RAD-140 does not reproduce this complete physiological environment.

It therefore should not be considered an equivalent replacement for Testosterone in men with confirmed hypogonadism.

Moreover, androgen-receptor activation from RAD-140 may suppress natural gonadotropin and testosterone production through negative feedback. A compound can therefore provide androgen-receptor stimulation while simultaneously impairing endogenous androgen production.

Dosing and Use

Testolone by Zyvex Pharmaceuticals contains 15 mg per tablet. A pack of 100 tablets therefore contains a stated total of 1,500 mg of RAD-140. This calculation describes package composition only.

The 15 mg tablet strength is not an approved or universally recommended dose.

There is no FDA-approved RAD-140 regimen for:

• Bodybuilding
• Muscle gain
• Strength enhancement
• Cutting
• Body recomposition
• Testosterone replacement

The published first-in-human oncology study used substantially different experimental doses under specialist clinical-trial supervision in patients with metastatic cancer. Those oncology study doses should not be extrapolated into bodybuilding recommendations because the population, objective, monitoring, and risk tolerance were fundamentally different.

There is therefore no validated bodybuilding cycle, loading schedule, escalation plan, SARM stack, or universal post-cycle regimen that can safely be inferred from a 15 mg tablet.

Female Use

RAD-140 is non-steroidal but remains an androgen-receptor agonist. Consequently, women may experience androgenic effects despite its SARM classification.

Potential concerns include:

• Acne or oily skin
• Menstrual irregularity
• Changes in libido
• Androgen-sensitive hair growth
• Scalp-hair changes
• Potential voice changes
• Other signs of virilization with substantial androgenic exposure

Notably, the principal published human RAD-140 trial involved postmenopausal women with metastatic breast cancer, but those findings should not be interpreted as evidence that RAD-140 is safe for healthy women or for performance enhancement.

Pregnancy presents a major concern because androgen-receptor agonism could interfere with normal fetal development.

The 15 mg tablet strength does not represent a validated female dose.

Comparative Analysis

Testolone vs Ligandrol

• RAD-140: Investigational SARM with published human oncology data demonstrating androgen-receptor engagement.
• LGD-4033: Investigational SARM with human research demonstrating effects on lean body mass and endocrine markers.
• Both may suppress endogenous androgen production.
• Neither is an approved bodybuilding drug.

Testolone vs Ostarine

• RAD-140: Experimental androgen-receptor modulator with a relatively limited human evidence base.
• Ostarine: Enobosarm/MK-2866, a SARM with broader clinical development in muscle-wasting and body-composition research.
• Both are non-steroidal but androgen-receptor active.

Testolone vs Testosterone

• RAD-140: Synthetic, non-steroidal selective androgen-receptor modulator.
• Testosterone: Endogenous steroid hormone with established replacement applications.
• Testosterone produces DHT and estradiol metabolites; RAD-140 does not reproduce those pathways.
• RAD-140 is not TRT.

Testolone vs Anavar

• RAD-140: Non-steroidal investigational SARM.
• Anavar: Oxandrolone, an orally active DHT-derived anabolic steroid.
• Both can produce androgen-receptor-mediated anabolic effects.
• Their chemical structures, metabolism, liver effects, and clinical histories differ.

Testolone vs MK-677

• RAD-140: Selective androgen receptor modulator.
• MK-677: Ghrelin-receptor agonist and growth-hormone secretagogue.
• MK-677 is not a SARM despite often being grouped with SARMs commercially.
• Their endocrine mechanisms are fundamentally different.

Testolone vs Traditional Anabolic Steroids

Traditional anabolic steroids are steroidal derivatives of Testosterone, DHT, or related hormones. RAD-140 is chemically non-steroidal but still acts through androgen receptors. The distinction may alter metabolism and tissue distribution, but it does not eliminate endocrine or systemic toxicity.

Conclusion

Testolone RAD-140 15 mg by Zyvex Pharmaceuticals contains 15 mg per tablet and is supplied in packs of 100 tablets. RAD-140 is an investigational, orally active selective androgen receptor modulator with demonstrated human androgen-receptor activity.

Although RAD-140 has attracted substantial interest for lean mass, strength, and body-composition applications, it is not an approved bodybuilding or TRT medicine. Human evidence remains limited, and published clinical research has documented significant liver-enzyme abnormalities and other adverse effects. Its non-steroidal structure does not eliminate endocrine suppression or other systemic risks. The 15 mg designation therefore represents stated tablet strength rather than a validated performance-enhancement regimen.