Dimethyltrienolone (R2956)
An extremely potent research androgen, 2,2-dimethyl analogue of metribolone (methyltrienolone), originally studied by Roussel-Uclaf as R2956. It was investigated as an antiandrogen research tool rather than a therapeutic and is far too toxic and suppressive for practical use. It appears occasionally as a designer steroid and on anti-doping lists; genuine human data are effectively nonexistent.
01 Overview
Dimethyltrienolone (R2956) is a 2,2-dimethyl derivative of methyltrienolone, itself one of the most potent androgens known. It was developed as a laboratory probe of androgen-receptor pharmacology and studied for antiandrogenic activity in some tissues, never intended as an anabolic therapeutic.
Like metribolone it is 17-alpha-methylated, making any oral use markedly hepatotoxic, and it is non-aromatising with strong progestogenic character. Its extreme receptor potency combined with toxicity means it has no legitimate performance role; it is documented mainly in pharmacology literature and as a designer-steroid flag for doping control. All practical claims about it are extrapolation, not human evidence.
02 Mechanism
Very high-affinity androgen-receptor ligand with mixed agonist/antagonist activity depending on tissue; 17-alpha-methylation confers oral activity and hepatotoxicity, and it does not aromatise.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Research only | 1–2 mg/day | Oral | No established human dosing; extreme potency and toxicity. Figures are illustrative only. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Potent androgen-receptor activityVery high receptor affinity demonstrated in laboratory assays; behaviour in humans uncharacterised. | Preclinical | ||
| Presumed strong anabolic effectInferred from receptor potency; no human efficacy data exist. | Unconfirmed |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Hepatotoxicity17-alpha-methylation predicts significant liver strain as with metribolone, which is regarded as too toxic for use. | Severe | Expected | Preclinical | |
| Severe HPTA suppressionExpected profound suppression given extreme androgen-receptor potency. | Severe | Expected | Unconfirmed |