What is RAD-140?
RAD-140, also called Testolone, is a selective androgen receptor modulator (SARM). It was developed by Radius Health, originally with a focus on neuroprotective properties and oncology questions. In performance research it is regarded as one of the strongest members of its class.
It is not a steroid but a small, orally available molecule. The appeal: hit the androgen receptor in muscle and bone without acting broadly where classic steroids cause trouble. How well that selectivity holds up across every endpoint is an open research question.
Comparison
At the androgen receptor in the lexicon
SARMs and testosterone use the same receptor, as stated in the TPD lexicon. Tap a card to open its entry.
Simplified: SARMs are meant to act tissue-preferentially, testosterone acts broadly and is also converted to oestrogen and DHT. 8
How it works
RAD-140 binds the androgen receptor and activates it with tissue preference: strong in muscle and bone, weaker in tissues like prostate or sebaceous glands. In preclinical models it showed a very high anabolic-to-androgenic ratio (over 90:1 in the original characterization).
Unlike testosterone, RAD-140 does not aromatize to estrogen and is not reduced to DHT. That changes the side-effect pattern but does not remove it, in particular the suppression of the body's own testosterone production remains.
Where it acts
Where RAD-140 acted in studies
Tap a point or a card. Colour = androgen receptor, grey = observed.
- Muscle
Activates the androgen receptor in muscle cells, measured in the lab8
AR - Liver
AST raised in 59.1 percent, plus case reports of liver injury3
Observed in trials - Blood values
SHBG fell in all 18 women measured3
Observed in trials - Heart
Case report of myocarditis in a young man6
Observed in trials
Targets in the ChEMBL database8
Compound CHEMBL1672635: one recorded mechanism, Agonist, Ki 7 nM, EC50 0.1 nM in muscle cells.
- Gene
- AR
- UniProt
- P10275
- ChEMBL
- CHEMBL1871
- Action
- Agonist, Ki 7 nM, EC50 0.1 nM in muscle cells
How to take it
RAD-140 is taken orally, no mixing, no injecting.
- Once daily, the roughly 45-hour half-life means one dose is enough.
- With some water, with or without food.
- Research cycles typically run over 8 weeks, followed by a break and axis recovery.
Dosing
Dosing
Dosing, titration and syringe
Loading the dosing information …
- Getting started and stepping up, drawn as a staircase
- Units on the U-100 syringe for every step
- How long one vial lasts
What the research shows
The original characterization (Miller, 2011) described RAD-140 as a potent, orally available SARM with a very high anabolic-to-androgenic ratio. A preclinical study (Yu, 2017) showed RAD-140 inhibits the growth of certain androgen-receptor-positive breast cancer models, the original oncology development track. The first study in humans (LoRusso, 2022, phase 1, 22 women with breast cancer) measured a half-life of 44.7 hours; the most common side effects were raised liver values.
On the risk side, RAD-140 is the SARM with the densest case literature on liver injury. A cleanly documented case of liver injury under RAD-140 was published in 2023 (Ladna). There are no human efficacy studies for muscle building in healthy people. No approval exists either.
Study results
What the trials measured
Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.
Signs that RAD-140 reaches the receptor3
22 women with advanced breast cancer, no comparison group
SHBG and PSA respond to androgens and served as signs that the receptor is activated. Median progression-free survival was 2.3 months.
Research status
Where the research stands
On ClinicalTrials.gov there is exactly one study for RAD140: the completed phase 1 study in breast cancer. There are no studies in healthy people or on muscle gain. As of 26 Oct 2026. 7
- Preclinical Preclinical: slows breast cancer models with androgen and oestrogen receptors
- Phase 1 1 trial, 1 completed
- Phase 2 no registered trial
- Phase 3 no registered trial
- Approval not yet
Apart from 1 phase 1 trial there is no registered trial in phase 2 or later. 7
Side effects
Documented in studies and case reports:
- Suppression of the body's own testosterone axis, dose-dependent, with recovery times of weeks.
- Falling HDL values, shifts in the lipid profile.
- Liver values: RAD-140 has the densest liver-injury case literature among SARMs, monitoring here is not optional.
- Anecdotally: irritability, aggression, sleep issues at higher doses.
Tolerability
Side effects in the phase 1 study
Share of women with the side effect during treatment. Without a placebo group, the disease itself contributes to some values.
| Event | RAD-140 |
|---|---|
| Severe side effect (grade 3 or 4)3 | 73% |
| AST raised3 | 59% |
| ALT raised3 | 46% |
| Bilirubin raised3 | 27% |
| Vomiting3 | 27% |
| Decreased appetite3 | 27% |
Side effects were attributed to RAD-140 itself in 77.3 percent, severe ones in 31.8 percent. Raised liver values and low phosphate were the most common severe findings (22.7 percent each).3
Practice
-
Start low, 10mg is usually enough, do not chase the upper end.
-
Limit cycles (often 8 weeks) and plan a real break afterwards.
-
In official competition RAD-140 is banned and detectable in urine for weeks (WADA S1.2).
-
Liver and blood values before and after a cycle make sense.
Storage
Store dry, cool and protected from light, out of reach of children. Keep the original container closed and mind the expiry date.
