Norbolethone
An early synthetic anabolic steroid first investigated in the 1960s and later resurfacing as the first BALCO-era designer steroid identified in an athlete sample (2002). Some limited mid-century human data exist for growth applications; modern doping use is essentially uncharacterised.
01 Overview
Norbolethone (13-ethyl-17-hydroxy-18,19-dinorpregn-4-en-3-one) was originally studied by Wyeth in the 1960s, including small trials in children with growth failure, but was abandoned commercially. Decades later it reappeared as an undetectable designer androgen when anti-doping chemists identified it in a cyclist's urine.
The surviving human literature is sparse and dated, and no modern pharmacokinetic work exists. Its use in sport was clandestine, making dose and effect data unreliable and largely anecdotal.
02 Mechanism
Androgen-receptor agonist of the 19-nortestosterone family; drives nitrogen retention and muscle protein synthesis with relatively low androgenic activity.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Historical | 1–5 mg/day | Oral | Approximate from mid-century growth studies; not a modern regimen. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Nitrogen retention / weight gainOlder human studies noted anabolic weight gain in growth-failure patients. | modest in old studies | Observational | |
| Anabolic activityAnimal assays showed anabolic effect typical of the 19-nor class. | unquantified | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HPTA suppressionSuppression of endogenous testosterone expected from a 19-nor androgen. | Severe | Expected | Observational | |
| Androgenic effectsAcne and oily skin reported historically. | Mild | Class-typical | Observational |