What RAD-140 Actually Is
RAD-140, sold under the name testolone, is a non-steroidal selective androgen receptor modulator. It was developed by Radius Health and first described in the literature by Miller et al. in 2011 in ACS Medicinal Chemistry Letters, as a preclinical characterisation in rodents and primates. That is where it starts: a molecule designed to hit the androgen receptor in muscle and bone while doing less at the prostate than testosterone would.
It is a genuine SARM, which is worth saying because most of what gets sold under that banner is not. MK-677 (ibutamoren) sits on the same shelf in every shop that sells either, and it is not a SARM at all — it is a growth hormone secretagogue with an entirely different mechanism. If you are trying to work out what you are actually looking at, start with what is and is not a SARM.
How It Works
Testosterone binds the androgen receptor everywhere it finds one, which is why it grows muscle and also acts on the prostate, skin and hair follicles. A SARM is an attempt to keep the first part and lose the rest: bind the same receptor, but with tissue selectivity, so the anabolic signal in muscle and bone arrives without the same activity elsewhere.
In the preclinical work, RAD-140 did that. It produced anabolic activity in muscle with less prostate stimulation than testosterone in the animal models used. Whether that selectivity holds in a human male taking it to get bigger is a separate question, and one nobody has run the trial to answer.
What Human Research Exists
This is the part that gets skipped everywhere else, so read it slowly.
There is exactly one first-in-human study
A phase 1 study published in Clinical Breast Cancer in 2022 enrolled 22 heavily pretreated postmenopausal women with ER+/HER2- metastatic breast cancer. It was a dose-escalation safety study in cancer patients — the objective was to find the maximum tolerated dose and characterise the pharmacokinetics, not to measure muscle or strength.
What that trial reported: the most frequent treatment-emergent adverse events were elevated AST in 59.1% of participants, elevated ALT in 45.5%, and raised total bilirubin. In other words, the single human trial of this compound found liver enzyme elevation in most of the people who took it. That is the headline finding, and it is the only human dataset there is.
There is no trial showing it builds muscle in people
A 2025 systematic review in Clinical Endocrinology gathered every randomised controlled trial of SARMs and physical performance it could find: nine trials, 970 patients, mean age 57. Six compounds were covered — LGD-4033, PF-06260414, GSK2881078, GTx-024, MK-0773 and OPK-88004.
RAD-140 is not on that list. Not because the review missed it, but because the trial does not exist. Every claim you will read about what RAD-140 does for lean mass in a healthy adult is extrapolated from rodents, or from someone's log.
What Is Documented Is the Harm
The human literature on RAD-140 is not efficacy data. It is case reports, and there are a lot of them.
Liver
Drug-induced liver injury linked to RAD-140 has appeared in the published record every year since 2020: ACG Case Reports Journal, 2020; Ochsner Journal, 2022; Journal of Medical Case Reports, 2023; Australian Prescriber, 2024, reporting severe liver injury after use for bodybuilding; and a 2025 case in ACG Case Reports Journal of cholestatic injury that needed corticosteroids to resolve.
No liver supplement has been shown to prevent SARM-induced liver injury. Monitoring liver enzymes may detect injury; it does not prevent it.
Heart
Case reports also describe acute myocarditis, myopericarditis and heart failure in users of RAD-140. These are individual cases, not incidence rates, and a case report cannot tell you how likely something is. It can tell you the thing happens.
Suppression, and tendons
Suppression of natural testosterone production follows from the mechanism — the body reads the androgen signal and turns down its own output. A 2025 systematic review in the American Journal of Sports Medicine on SARM abuse in athletes also flags tendon rupture alongside liver injury and myocarditis.
You Probably Are Not Getting RAD-140
Before any of the above matters, there is the question of what is actually in the bottle. A 2017 analysis published in JAMA bought 44 products sold online as SARMs and put them through a WADA-accredited lab.
- Only 23 of 44 (52%) contained any SARM at all.
- 17 (39%) contained a different unapproved drug — including ibutamoren, GW501516 and SR9009.
- 4 (9%) contained no active compound whatsoever.
- 11 (25%) contained substances not listed on the label.
- Only 18 (41%) matched the amount of active compound the label claimed.
That is the base rate for this market. Every risk described further up assumes you got the compound on the label; roughly half the time you did not, and a quarter of the time you got something nobody told you about.
Where Ireland Stands
RAD-140 is not an authorised medicine in Ireland. Advertising unauthorised human medicines is prohibited; supply and import are subject to legal restrictions. Check current HPRA and Revenue guidance.
Sport status: RAD140 is named under S1.2 (SARMs) and prohibited at all times. See the WADA 2026 Prohibited List.
The Short Version
- RAD-140 (testolone) is a real SARM, unlike MK-677, which is sold as one and is not.
- One first-in-human trial exists: 22 breast cancer patients, and its main finding was liver enzyme elevation in 59.1% (AST) and 45.5% (ALT) of participants.
- No randomised trial has ever tested RAD-140 for muscle or physical performance in humans. The 2025 systematic review of SARM performance RCTs covers six other compounds.
- The human record that does exist is case reports: drug-induced liver injury every year since 2020, plus myocarditis, myopericarditis, heart failure and tendon rupture.
- Liver supplements have no evidence of preventing SARM liver injury. Bloodwork detects a problem; it does not stop one.
- Suppression of natural testosterone is a risk associated with androgen-receptor stimulation.
- In a JAMA analysis, only 52% of products sold as SARMs contained a SARM and only 41% matched their own label.
- No HPRA or EMA licence in Ireland. Banned by WADA at all times.
Related Reading
SARMs in Ireland: what they are, what they are not, and where the law sits · MK-677 (ibutamoren): not a SARM, and not approved · Why I test bloods before changing anything