RAD-140 (Testolone): What Researchers Need to Know in 2026

Among the compounds that have attracted serious scientific and performance-research attention over the past decade, RAD-140 — trademarked as Testolone — stands in a category of its own. As a non-steroidal selective androgen receptor modulator (SARM), it was engineered from the ground up to deliver anabolic tissue selectivity without the systemic hormonal burden associated with exogenous androgens. This overview covers everything the research community currently knows about RAD-140, from its molecular mechanism to its published study data, community-reported protocols, and where it fits within the broader SARM landscape in 2026.

What Is RAD-140?

RAD-140 (chemical name: 2-chloro-4-[[(1R,2S)-1-[5-(4-cyanophenyl)-1,3,4-oxadiazol-2-yl]-2-hydroxypropyl]amino]-3-methylbenzonitrile) is a synthetic, orally bioavailable SARM developed by Radius Health, Inc. Originally investigated as a potential alternative to testosterone replacement therapy for hypogonadism and as a treatment for hormone-receptor-positive breast cancer, RAD-140 entered the SARM conversation early because of its exceptionally high anabolic-to-androgenic ratio — reported at approximately 90:1 in preclinical testing — far exceeding that of testosterone (1:1).

Unlike testosterone or traditional anabolic steroids, RAD-140 binds selectively to androgen receptors concentrated in skeletal muscle and bone while demonstrating reduced activity at androgen receptors in the prostate and other androgen-sensitive tissues. This selectivity is the foundational premise of the entire SARM class: tissue-targeted anabolism with a narrower side-effect window than classic androgens.

Research Overview

RAD-140’s published preclinical data established several notable biomarkers that drove its widespread research interest. Institutional and peer-reviewed research has explored RAD-140 across three primary domains:

Muscle and body composition research: A study published in Clinical and Experimental Pharmacology & Physiology (Brown et al., 2023) examined 10 weeks of RAD-140 supplementation in female mice across strength, eccentric-contraction recovery, and overall health span. The compound increased frailty indices and mortality risk at the 5 mg/kg dosage tested, while failing to improve strength output relative to controls — a finding that underscores the dose-dependency and context-sensitivity of SARM research. (DOI: 10.1111/1440-1681.13824)

Cardiovascular safety signals: A case report in Cureus (Padappayil et al., 2022) documented acute myocarditis in a young male following self-administration of RAD-140 for bodybuilding, highlighting the importance of supervised research protocols and clinical monitoring. (DOI: 10.7759/cureus.21663)

Neuroprotective mechanisms: Earlier preclinical data (Jayaraman et al., 2014, Endocrinology) demonstrated that RAD-140 activated neuroprotective signaling pathways in rat models — specifically the MAPK/ERK cascade — at levels comparable to testosterone, while avoiding testosterone’s apoptotic effects on neurons at higher concentrations. This remains one of the compound’s most scientifically distinctive findings. (PubMed: 24384845)

For additional research literature, search RAD-140 on PubMed and Google Scholar.

Community Discussion

The broader research and fitness community has generated a substantial body of anecdotal data on RAD-140 over the past several years. The r/sarmssourcetalk and r/PEDs communities on Reddit contain thousands of documented self-experimentation logs covering dose ranges, cycle lengths, strength and body composition outcomes, and reported side effects. Common themes include significant increases in training capacity within the first two to four weeks, notable lean mass accretion over 8–12 week research windows, and measurable suppression of endogenous testosterone requiring post-cycle consideration.

Potential Benefits Studied

• Skeletal muscle anabolism: Selective activation of muscle androgen receptors with high binding affinity, producing protein synthesis upregulation in preclinical models.
• Bone density support: Androgen receptor agonism in osteoblasts, studied as a potential intervention for osteoporosis and muscle-wasting diseases.
• Neuroprotection: Activation of the MAPK/ERK and PI3K/Akt pathways in neuronal tissue, with early data suggesting reduced amyloid-beta sensitivity — relevant to neurodegenerative disease research.
• Breast cancer research: Investigated in HR+/HER2- breast cancer models, with Radius Health conducting Phase I/II clinical trials (NCT02971761) as an AR agonist therapy.
• Fat-free mass preservation: High anabolic selectivity ratio (≈90:1 vs. testosterone’s 1:1) positions it as a candidate for muscle-preserving protocols in caloric deficit research.

Dosage & Administration

In the peer-reviewed and clinical-trial literature, RAD-140 dosing in human studies has ranged from 50–150 mg/day (Radius Health oncology trials), though the research community working with it in body-composition contexts typically uses substantially lower doses — commonly cited in community protocols between 5–20 mg/day orally, with 10 mg frequently described as a starting reference point for experienced researchers. Half-life estimates from pharmacokinetic modeling suggest approximately 16–20 hours, making once-daily dosing appropriate for maintaining consistent receptor occupancy. Research cycle lengths observed in the community typically range from 8 to 12 weeks, followed by appropriate post-cycle hormone management.

It should be noted that all dosing information above is drawn from published literature and community documentation for research reference only. RAD-140 is not approved for human use by the FDA or any equivalent regulatory authority.

Where to Find It

For researchers sourcing reference-grade RAD-140, Combat Research carries RAD-140 (Testolone) — formulated and tested for research applications.

Conclusion

RAD-140 occupies a genuinely interesting position in the SARM research landscape: it is one of the most clinically advanced compounds in its class, having progressed to formal oncology trials, while simultaneously generating one of the richest bodies of community-documented body-composition research. The mechanistic data on neuroprotection adds a layer of scientific interest that extends well beyond simple anabolic applications. As with all investigational compounds, rigorous protocol design, biomarker monitoring, and thorough literature review are essential components of responsible research.

Disclaimer

This article is for educational and research purposes only. RAD-140 is not approved by the FDA for human use. Nothing on this page constitutes medical advice. Combat Research products are intended for laboratory and research use only. Consult a licensed healthcare provider before using any investigational compound.