Nandrolone

Nandrolone is a synthetic derivative of testosterone that lacks the carbon-19 methyl group, hence the name 19-nortestosterone ^[1]. Like other anabolic-androgenic steroids it acts on the androgen receptor, but it is characterized by relatively strong anabolic, or tissue-building, effects and comparatively weak androgenic, or masculinizing, effects, a profile that made it attractive for therapeutic use ^[1]. It is almost always administered as an oil-based intramuscular injection of an ester; nandrolone phenylpropionate acts more quickly and briefly, while nandrolone decanoate is longer-acting, and the choice of ester, injection site, and volume all shape its pharmacokinetics ^[2]. First synthesized in 1950, it entered clinical use later that decade.

Historically nandrolone was prescribed for anemia, osteoporosis, and states of muscle loss. Controlled evidence supports an anabolic effect; in a randomized, double-blind trial in patients on dialysis, weekly nandrolone decanoate significantly increased lean body mass and improved measures of physical function compared with placebo ^[3]. Similar benefits on body composition have been examined in other wasting conditions. In many countries such indications have narrowed as other treatments emerged, and prescribing today is limited, but the anabolic properties that gave it medical utility are the same ones that drive its non-medical use for physique and performance enhancement ^[1].

Nandrolone is among the most commonly used anabolic steroids for bodybuilding, where doses far exceed any therapeutic range ^[1]. Its use is prohibited in sport and detectable through characteristic urinary metabolites, and it has been banned from Olympic competition since the 1970s. Adverse effects include suppression of the body's own testosterone production, sexual dysfunction sometimes called deca dick, mood changes, fluid retention, and, with high or prolonged use, cardiovascular strain; masculinizing effects can occur in women ^[1]. Legally it is a controlled substance in numerous jurisdictions, classified as Schedule III in the United States and Class C in the United Kingdom ^[1].

As a 19-nortestosterone injectable, nandrolone strongly suppresses the HPT axis, blunting endogenous testosterone and typically requiring a post-cycle recovery protocol. Its progestogenic activity and low central DHT conversion are associated with sexual dysfunction (the so-called "deca dick"), and aromatization plus progestogenic signaling can drive gynecomastia and fluid retention. Cardiovascular strain is well documented; it suppresses HDL cholesterol, can raise blood pressure, and elevates hematocrit, increasing thrombotic risk. In women it carries virilization risk (voice deepening, hirsutism, menstrual disruption), and its long ester means adverse effects clear slowly. Mood disturbance and hepatic strain are also reported, the latter milder than with oral 17-alkylated steroids.