Nandrolone is an anabolic androgenic steroid derived from testosterone, primarily used to treat conditions associated with muscle wasting, severe anemia, and osteoporosis in specific clinical settings. It was developed in the 1960s and has since been used in both medical and, controversially, non-medical contexts due to its strong anabolic (tissue-building) effects.
Its history is marked by its ability to promote increased protein synthesis, muscle mass, and bone density, making it useful in patients suffering from chronic wasting diseases. However, its clinical use has become limited in many countries due to concerns about abuse potential, androgenic side effects, and long-term safety risks, including cardiovascular complications and hormonal imbalance. Despite this, it remains available in some regions under strict medical supervision for specific indications.
BRAND NAMES
Deca-Durabolin (nandrolone decanoate; most widely known brand)
Durabolin (nandrolone phenylpropionate)
Retabolil (used in some international markets)
MECHANISM OF ACTION
Nandrolone is an anabolic androgenic steroid that acts by binding to androgen receptors (ARs) located in various tissues, including skeletal muscle and bone. After binding, the drug–receptor complex enters the nucleus and regulates gene transcription, leading to increased synthesis of structural proteins.
PHARMACOKINETICS
Absorption
Nandrolone is not active orally due to extensive first-pass hepatic metabolism. It is therefore administered via intramuscular injection in esterified forms (e.g., decanoate or phenylpropionate). After injection, it is slowly absorbed from the muscle depot into systemic circulation, with the rate of absorption depending on the ester type (long-acting formulations provide sustained release over days to weeks).
Distribution
Nandrolone is widely distributed into tissues, particularly skeletal muscle and bone, where androgen receptors are abundant. It has high lipid solubility and is moderately bound to plasma proteins. Because of its anabolic nature, it shows significant tissue uptake and prolonged biological activity compared with its plasma half-life.
Metabolism
Nandrolone undergoes hepatic metabolism, primarily via reduction and hydroxylation pathways, followed by conjugation (glucuronidation and sulfation). It is converted into several inactive metabolites, including 19-norandrosterone and 19-noretiocholanolone, which are used as biomarkers in drug testing.
Elimination
Excretion occurs mainly through the urine, with metabolites eliminated as conjugated compounds. A smaller fraction is excreted in feces. The elimination half-life varies depending on the ester form, ranging from several days (phenylpropionate) to weeks (decanoate), reflecting its prolonged depot release.
PHARMACODYNAMICS
Nandrolone exerts its effects by binding to androgen receptors (ARs) in target tissues, forming a receptor–hormone complex that regulates gene transcription. This increases protein synthesis, nitrogen retention, and erythropoiesis, leading to enhanced muscle growth, improved recovery, and increased bone density. It has a relatively higher anabolic-to-androgenic ratio compared to testosterone, although androgenic effects are still present.
ADMINISTRATION
Nandrolone is administered intramuscularly as an esterified injectable formulation. It is typically used under medical supervision in conditions involving muscle wasting, anemia, or osteoporosis, with dosing intervals determined by the ester duration.
DOSAGE AND STRENGTH
Dosing varies by indication and formulation. Common regimens include 50–100 mg weekly or every 2–4 weeks (phenylpropionate) or 100–200 mg every 2–4 weeks (decanoate), adjusted based on clinical response and tolerance.
DRUG INTERACTIONS
Nandrolone can interact with several medications, mainly through its effects on hormones, coagulation, and metabolism. When used with anticoagulants such as warfarin, it may enhance anticoagulant effects and increase the risk of bleeding by altering clotting factor production.
CONTRAINDICATIONS
Nandrolone is contraindicated in several conditions where its androgenic and anabolic effects may worsen the underlying disease state. It should not be used during pregnancy or breastfeeding, as it may cause virilization of the fetus or infant and disrupt normal development.
SIDE EFFECTS
Acne and oily skin
Fluid retention and edema
Mood changes or irritability
Increased libido
Gynecomastia (in males)
Virilization in females (deepening voice, hirsutism)
OVER DOSAGE
Overdosage of nandrolone is generally associated with exaggeration of its pharmacological and androgenic effects, rather than an acute life-threatening toxicity. Acute symptoms may include nausea, vomiting, abdominal discomfort, fluid retention, and edema, along with mood changes such as irritability or aggression.
TOXICITY
Chronic or excessive use of nandrolone can lead to cardiovascular complications (hypertension, dyslipidemia), endocrine suppression (testicular atrophy, infertility), and hepatic strain, particularly with long-term misuse. Psychological effects such as aggression and dependence-like behavior may also occur.
