RESEARCH MONOGRAPH · KDC-MN-263

Testolone (RAD-140)

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 3 min read

Our opinion on this compound

45/100

High-potency SARM with the messiest safety signal in the class, including drug-induced liver injury case reports

RAD-140 is the SARM where the hype-to-evidence ratio gets uncomfortable. Radius Health discovered it as a high-potency, orally bioavailable non-steroidal AR agonist intended for muscle wasting and breast cancer indications. The breast cancer program (RAD140 plus fulvestrant) reached phase 1 in AR-positive metastatic disease before being deprioritized. The healthy-volunteer pharmacology data is sparse compared to ostarine or even LGD-4033, and most of what circulates in consumer-facing material is extrapolated from animal work.

The mechanism is consistent with the class. High-affinity AR agonism with preferential muscle/bone tissue selectivity over prostate. The selectivity ratio in animal models is favorable, but the in-human dose-response on suppression suggests the practical selectivity at performance-relevant exposures is mediocre at best.

What we dont like is the safety signal. Multiple published case reports of drug-induced liver injury attributed to RAD-140, several severe enough to require hospitalization. The reports are not numerous in absolute terms but the consistent hepatic injury pattern (cholestatic, sometimes mixed) across independent cases is the kind of signal that would have killed the development program in formal clinical trials. The suppression at typical gray-market doses (10-to-30 mg per day) is also severe and slow to recover.

The FDA issued warnings in 2017 and 2020 specifically calling out RAD-140 in supplement adulteration contexts, and the 2023 case series in J Med Tox put a sharper point on the hepatotoxicity concern. This isnt people piling on; the underlying signal is real.

What we like, in narrow research-tool terms, is that RAD-140 is a useful high-affinity AR agonist reference compound for in vitro work, and the breast-cancer adjuvant rationale (AR agonism as a potential strategy in AR-positive disease) is mechanistically interesting even if the clinical translation has been slow.

Sourcing is dominated by gray-market product with severe quality concerns. Research-grade material exists but verification is essential, and the high potency of RAD-140 makes mislabeling consequences worse than for less potent SARMs.

Overhyped relative to human evidence, with a safety signal that should be more prominent in the consumer narrative than it is. For research-tool purposes the in vitro AR pharmacology is well-characterized; everything beyond that should be treated as hypothesis, not fact.

Evidence: 35
Mechanism: 65
Reliability: 55
Safety: 30
Sourcing: 40
Value: 40
Signal: 60
Staying power: 35

Plain-language summary Intrigue 65 / 100

Testolone (RAD-140) is a high-potency SARM developed by Radius Health, originally for muscle wasting and later pivoted to androgen-receptor-positive metastatic breast cancer. In animal studies it produced anabolic effects exceeding testosterone propionate at the same molar dose while sparing the prostate. Phase 1 trials in postmenopausal women with breast cancer showed acceptable safety, but development for muscle wasting did not proceed. It is among the most popular SARMs in recreational use, prized for its potency, but it also produces strong hormonal suppression and elevated liver enzymes have been reported. WADA-banned. Long-term safety data in healthy people are essentially nonexistent. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Selective androgen receptor modulator (high-potency)

A potent non-steroidal SARM developed for muscle wasting and breast cancer; one of the highest-potency SARMs by binding affinity.

Abstract

Testolone (RAD-140; CAS 1182367-47-0; molecular formula C20H16ClN5O2; molecular weight 393.83) is a non-steroidal SARM developed by Radius Health for muscle wasting and (subsequently) AR-positive metastatic breast cancer. The compound is a high-potency AR ligand (Ki approximately 7 nM with high intrinsic activity) and a tissue-selective agonist; preclinical studies demonstrated anabolic activity in skeletal muscle exceeding that of testosterone propionate at equivalent molar doses, with reduced prostate effects. Phase 1 trials in postmenopausal women with metastatic breast cancer demonstrated dose-dependent AR pathway engagement; the program was advanced into phase 2. The compound is among the most widely used SARMs recreationally despite no regulatory approval. Plasma half-life is approximately 60 hours, supporting dosing. The principal safety concerns are HPG axis suppression and hepatic enzyme elevation at supratherapeutic doses; long-term safety data are absent.

Mechanism of action

Non-steroidal SARM with high anabolic potency exceeding testosterone in preclinical models. Tissue-selective AR agonism.

Reported research dose ranges

Trial doses 0.1 to 0.3 mg/kg in the published literature; recreational use 10 to 30 mg.

References

Miller CP, et al. Design, synthesis, and preclinical characterization of RAD140, a selective androgen receptor modulator. ACS Med Chem Lett 2010.
Jayaram BM, et al. RAD140 is neuroprotective and reduces neuropathology in transgenic mouse models of Alzheimer's disease. PLoS ONE 2017.
Solomon ZJ, et al. Selective androgen receptor modulators: current knowledge and clinical applications. Sex Med Rev 2019.

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KDC-MN-263

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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Testolone (RAD-140)

Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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