JNJ-28330835
JNJ-28330835 is a non-steroidal selective androgen receptor modulator investigated by Johnson & Johnson in preclinical studies, notable for showing anabolic effects on muscle while acting as an antagonist or weak agonist in the prostate. It has no published human data and is essentially a research tool compound.
01 Overview
JNJ-28330835 was studied in rodent models of androgen action, where it increased levator ani muscle mass — a classic anabolic readout — while producing a dissociated, more favourable prostate profile than testosterone. This tissue selectivity is the defining property SARM programmes pursue.
Despite reasonable preclinical characterisation, the compound did not progress to disclosed human trials. It appears in the scientific literature as a comparator SARM and occasionally on grey-market listings, but there is no clinical pharmacology to inform human dosing or safety.
02 Mechanism
A non-steroidal androgen receptor modulator with tissue-selective agonism — anabolic in muscle while showing reduced or antagonist activity in the prostate in animal models.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Preclinical only | 0 mg/day | Oral | No human dosing exists; studied only in animal models. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Muscle anabolismIncreased skeletal muscle mass in animal androgen models. | Rodent | Preclinical | |
| Prostate-sparing selectivityShowed reduced prostate stimulation compared with testosterone in animals. | Preclinical | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Presumed HPTA suppressionExpected androgen-receptor-mediated suppression of endogenous testosterone, undocumented in humans. | Moderate | Unknown | Unconfirmed | |
| Unknown human safetyNo clinical data exist for this preclinical compound. | Moderate | Unknown | Unconfirmed |