RAD-140, also sold to labs as Testolone, has a strange split personality in the literature. On one side there’s a tidy pharma story: Radius Health designed it as an oral, nonsteroidal SARM and later took it into women with metastatic breast cancer. On the other side there’s a growing pile of case reports from emergency rooms. We think you need both halves to read RAD-140 research honestly, so that’s what this overview covers, with every paper linked.
Key findings
- Radius Health described RAD-140 in 2011 as a potent, orally bioavailable, nonsteroidal SARM (Miller et al.).
- In breast cancer cells it acted as an AR agonist, yet it did not activate AR in prostate cancer cells, and it slowed growth of AR/ER+ patient-derived xenografts (Yu et al., 2017).
- The only published human trial (22 women, NCT03088527) measured a half-life of 44.7 hours.
- In that same trial, AST rose in 59.1% of participants and ALT in 45.5%.
- Mouse data cut both ways: worse frailty scores in young and adult females in one study, better cardiac function in old mice in another.
Where RAD-140 came from
RAD-140 was built at Radius Health in Cambridge, Massachusetts. The discovery paper, published by Miller and colleagues in ACS Medicinal Chemistry Letters, calls it a potent, orally bioavailable, nonsteroidal selective androgen receptor modulator and walks through its testing in several preclinical models of anabolic androgen action [1].
The pitch behind any SARM is simple. Testosterone hits the androgen receptor everywhere, prostate included. A SARM is supposed to hit it hard in muscle and bone and go easy on reproductive tissue. Whether a given molecule actually pulls that off is the whole question, and it’s never a yes or no.
A quick note on names. You’ll see “Testolone” all over the internet. It isn’t a name the original papers use; they say RAD140. We use both here because that’s how people search.
How it acts on the androgen receptor
The most detailed mechanism paper came from Radius itself. Yu and colleagues ran binding assays against four nuclear receptors and found RAD-140 bound AR with high affinity and specificity [2]. Here’s the interesting part. It switched AR on in breast cancer cells but not in prostate cancer cells.
In breast cancer models it also suppressed the estrogen receptor pathway, including the ESR1 gene itself. Given orally, it substantially slowed the growth of AR/ER+ patient-derived xenografts, and pairing it with palbociclib worked better than either alone in those models [2].
Tissue selectivity showed up in the brain work too. In Jayaraman’s 2014 study, RAD-140 was as good as testosterone at cutting apoptotic death in cultured rat hippocampal neurons, and that protection depended on MAPK/ERK signaling [3]. In castrated adult male rats it protected hippocampal neurons from kainate while largely sparing the prostate.
One caveat we’d flag: two of these three papers have Radius authors. That’s normal for an early compound. It’s still worth knowing.
Pharmacokinetics and the half-life question
Older blog posts throw around a lot of half-life figures. The one number we can actually trace to human data is 44.7 hours. It comes from the first-in-human phase 1 trial (LoRusso et al., 2022), which enrolled 22 postmenopausal women with ER+/HER2- metastatic breast cancer [4]. That long half-life is why the trial gave it once daily.
The trial also tracked two surrogate markers of AR engagement. SHBG fell in 18 of 18 patients and PSA went up in 16 of 20. Paired tumor biopsies backed up target engagement.
Keep the context in mind, though. This was a small group of heavily pretreated cancer patients, not healthy volunteers. We wouldn’t lean on that half-life for any other population.
Metabolism has its own small literature, mostly from anti-doping chemists. Wagener and colleagues at the German Sport University Cologne ran six very-low-intake excretion studies with five adult male volunteers each, found several urinary metabolites never described before, and mapped how long each stayed detectable [5]. The same paper notes RAD-140 is prohibited at all times by the World Anti-Doping Agency.
What the clinical trials actually show
ClinicalTrials.gov lists the Radius study as NCT03088527, a completed phase 1 that ran from October 2017 to September 2020 and is now sponsored by Stemline Therapeutics.
Results were modest. At the maximum tolerated level, one patient with a baseline ESR1 mutation had a partial response. Clinical benefit rate at 24 weeks was 18.2% and median progression-free survival was 2.3 months [4].
The safety numbers deserve more attention than they usually get. Elevated AST showed up in 59.1% of patients, ALT in 45.5% and total bilirubin in 27.3%. Grade 3 or 4 adverse events hit 72.7%, though not all were judged drug related. So when people call RAD-140 “liver friendly”, the only human trial doesn’t back them up.
You’ll also read that RAD-140 lives on under a newer company code. We couldn’t confirm that link from a primary source, so we’ve left it out.
Animal studies, good and bad
This is where things get messy, and honestly more interesting.
In 2023, Brown and colleagues gave young and adult female mice RAD-140 for 10 weeks. Frailty scores and mortality risk went up compared with controls, adaptive potential dropped in the young group, and torque didn’t improve [6]. Their read: in female mice it may do more harm than good for sarcopenia research.
A 2025 rat study pointed the other way, at least on muscle. Puskas and colleagues found RAD-140 alone raised muscle fiber cross-sectional area versus vehicle in young male rats, but it added nothing significant on top of functional overload and didn’t change tibial bone structure after 14 days [7].
Then there’s the heart. Heinze’s group treated 23-month-old mice for six weeks and saw higher ejection fraction (+10.4%), stroke volume and cardiac output in both sexes, with extra strain improvements only in males [8]. No structural changes turned up. Sex keeps showing up as a variable, and we suspect that’s going to matter a lot going forward.
| Study | Model | Main finding |
|---|---|---|
| Yu 2017 | Breast cancer PDX | Tumor growth slowed, ESR1 suppressed |
| Jayaraman 2014 | Rat neurons, castrated rats | Neuroprotection, prostate largely spared |
| Brown 2023 | Female mice, 10 weeks | Frailty and mortality risk up |
| Puskas 2025 | Young male rats, 14 days | Fiber area up, no bone change |
| Heinze 2026 | Old mice, 6 weeks | Better cardiac function, more so in males |
Safety signals from case reports
Outside the lab, RAD-140 keeps appearing in medical journals for the wrong reasons. Ladna and colleagues described a 26-year-old man with jaundice and acute liver injury where workup found no cause other than RAD-140. His liver panel normalized by two months after he stopped [9].
Heart problems show up too. Padappayil’s 2022 report describes a young man with possible acute myocarditis after taking it [10]. Case reports can’t prove cause, of course. But taken alongside the liver enzyme numbers from the phase 1 trial, the pattern is hard to wave away.
For more on related compounds, see our library entries for RAD-140, LGD-4033 and ostarine.
FAQ
What is the half-life of RAD-140? The only human measurement, from the 2022 phase 1 trial in women with metastatic breast cancer, was 44.7 hours [4].
Is RAD-140 FDA approved? No. It has only been tested in early-phase clinical research.
References
- Miller CP, Shomali M, Lyttle CR, et al. Design, Synthesis, and Preclinical Characterization of the Selective Androgen Receptor Modulator (SARM) RAD140. ACS Med Chem Lett. 2011. PMID 24900290
- Yu Z, He S, Wang D, et al. Selective Androgen Receptor Modulator RAD140 Inhibits the Growth of Androgen/Estrogen Receptor-Positive Breast Cancer Models with a Distinct Mechanism of Action. Clin Cancer Res. 2017. PMID 28974548
- Jayaraman A, Christensen A, Moser VA, et al. Selective androgen receptor modulator RAD140 is neuroprotective in cultured neurons and kainate-lesioned male rats. Endocrinology. 2014. PMID 24428527
- LoRusso P, Hamilton E, Ma C, et al. A First-in-Human Phase 1 Study of a Novel Selective Androgen Receptor Modulator (SARM), RAD140, in ER+/HER2- Metastatic Breast Cancer. Clin Breast Cancer. 2022. PMID 34565686
- Wagener F, Euler L, Görgens C, Guddat S, Thevis M. Human In Vivo Metabolism and Elimination Behavior of Micro-Dosed Selective Androgen Receptor Modulator RAD140 for Doping Control Purposes. Metabolites. 2022. PMID 35888790
- Brown AM, Ganjayi MS, Baumann CW. RAD140 (Testolone) negatively impacts skeletal muscle adaptation, frailty status and mortality risk in female mice. Clin Exp Pharmacol Physiol. 2023. PMID 37758180
- Puskas J, Guda T, Niccoli S, et al. Preclinical assessment of the selective androgen receptor modulator RAD140 to increase muscle mass and bone mineral density. Physiol Rep. 2025. PMID 40680216
- Heinze SS, Sapp DG, Young AP, Howlett SE. Treatment with a selective androgen receptor modulator (RAD140) is linked to better cardiac function, with male-specific effects that are graded by interleukin-6. Geroscience. 2026. PMID 41703239
- Ladna M, Taylor K, Bhat A, Dideban B. Idiosyncratic drug-induced liver injury related to use of novel selective androgen receptor modulator RAD140 (Testalone): a case report. J Med Case Rep. 2023. PMID 36978171
- Padappayil RP, Chandini Arjun A, Vivar Acosta J, Ghali W, Mughal MS. Acute Myocarditis From the Use of Selective Androgen Receptor Modulator (SARM) RAD-140 (Testolone). Cureus. 2022. PMID 35233331
Disclaimer: This content is intended for research purposes only and is not meant to constitute medical advice.
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