What it is
RAD-140, also called Testolone, is a SARM (selective androgen receptor modulator). It is an orally active molecule designed to stimulate the androgen receptor in muscle and bone with the aim of building muscle and strength while having less effect on other tissues than traditional anabolic steroids.
Important framing for this forum: RAD-140 is not a peptide. It is a small synthetic non-steroidal drug. We cover it here for completeness, but it is a different class of compound with a very different risk profile from the nootropic peptides. It was investigated by Radius Health in early-stage (Phase 1) human trials in a breast cancer setting, then the program was paused. It is not approved for human use anywhere, and it is banned in sport (WADA lists SARMs as anabolic agents).
What people use it for
People use RAD-140 to gain muscle mass and strength, often viewing it as one of the more “potent” SARMs. There is no approved indication for athletic or cosmetic use. The human efficacy data for body composition in healthy people is thin; the reputation is largely anecdotal and from animal work.
Typical dose range
There are no approved or validated dosing guidelines. Reported recreational use is commonly 10 to 20 mg per day for around 6 to 8 weeks. Higher doses and longer runs increase suppression and side-effect risk without good evidence of being worth it.
Note on the calculator: RAD-140 is taken orally, so there is no reconstitution step the way there is with injectable peptides. The dosing calculator at Peptide Calculator - Reconstitution & Dosage | Buy Peptides UK is built for reconstituting and dosing injectable/lyophilised compounds, so it does not really apply to an oral SARM. It is linked here only for consistency with the rest of the library.
Half-life and frequency
Reported half-life is long, roughly 20 to 60 hours, with Phase 1 data describing around 44.7 hours. A half-life in that range means once-daily dosing is enough to maintain steady levels, and it also means the compound and its suppression of your hormones clear slowly after you stop.
How it is taken (oral vs injectable, reconstitution if relevant)
RAD-140 is taken orally (capsules or a liquid/oral solution). There is no reconstitution. This also means it passes through the liver, which matters for the liver-injury risk noted below.
Common side effects (including suppression)
- Testosterone suppression: this is the headline risk and it is real and dose-dependent (see the next section).
- Liver injury: multiple published case reports document drug-induced liver injury with RAD-140, including a cholestatic pattern (jaundice, very high bilirubin, itching) in young men after only weeks of use. In the reported cases the injury resolved after stopping, but this is a serious, documented harm, not a theoretical one.
- Lipids: SARMs as a class tend to lower HDL (“good” cholesterol), which is a cardiovascular concern.
- Mood and aggression changes, headaches, and lethargy are commonly reported anecdotally.
- Product contamination: independent testing has repeatedly found SARM products that are mislabeled, underdosed, overdosed, or contain a different compound entirely. You often do not actually know what you are taking.
PCT and recovery (SARMs)
RAD-140 is one of the more suppressive SARMs. In the Radius Health Phase 1 trial it produced dose-dependent suppression of testosterone and gonadotropins (LH and FSH) in men. Anecdotally, users report total testosterone dropping below 200 ng/dL after 6 to 8 weeks at 20 mg/day, which is into a frankly low range.
What suppression means in practice: your body slows or stops its own testosterone production while the drug is active. Symptoms can include low libido, erectile issues, fatigue, low mood, and (if it is not allowed to recover) longer-term hormonal problems.
Post-cycle therapy (PCT): because of how suppressive RAD-140 is, a PCT with a SERM (selective estrogen receptor modulator) such as enclomiphene, tamoxifen (Nolvadex), or clomiphene (Clomid) is standard in recreational protocols to help restart the natural axis. These are themselves prescription drugs with their own side effects. PCT is typically started a couple of days after the last dose, timed against the compound’s long half-life.
The only honest way to know your status is bloodwork: a sensible panel is total and free testosterone, LH, FSH, oestradiol, liver enzymes (ALT/AST), and a lipid panel, ideally before, during, and after. Recovery is not guaranteed to be fast or complete, and the more suppressive the compound and the longer the run, the bigger the risk.
Evidence grade
Weak for the uses people actually want it for. Human data is limited to early-stage trials in a cancer setting (not muscle-building in healthy people), the development program was paused, and most “evidence” for physique use is anecdotal or from animals. By contrast, the suppression and the liver-injury case reports are well enough documented to take seriously. So the harms have more solid grounding than the benefits.
Honest unknowns
- Long-term safety in healthy users is essentially unknown.
- True rate and severity of liver injury is unknown; case reports establish it happens, not how often.
- How fully and how quickly the hormonal axis recovers varies between people and is not guaranteed.
- Real-world product purity and dosing are unreliable, so even careful “protocols” rest on shaky inputs.
- Cardiovascular impact of the HDL reduction over time is not well characterised.
Research use only. Not medical advice. 18+.