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High riskCardiotoxic

Deca Durabolin

Nandrolone Decanoate · Deca

Deca Durabolin is a brand of nandrolone decanoate, a long-acting injectable anabolic-androgenic steroid (AAS) in the 19-nortestosterone (19-nor) class. Medically it has been studied and used for HIV/AIDS-associated wasting, anemia of chronic kidney disease, and osteoporosis in older women, where controlled trials show it increases lean body mass, muscle strength, bone mineral density, and hemoglobin. It is widely used non-medically at supraphysiologic doses to increase muscle mass. The main risks are: it strongly suppresses the body's own testosterone and sperm production (often for a prolonged, variable period after stopping); it worsens the cholesterol profile (notably lowering HDL); observational data in long-term high-dose AAS users show high blood pressure, thickened heart walls, and impaired heart relaxation/subclinical contractile dysfunction; it raises red-cell mass (polycythemia) and has been linked in case reports to serious blood clots; and in women it causes irreversible virilization. It is not liver-toxic in the way oral 17-alpha-alkylated steroids are, but that does not make it safe. Because its decanoate ester is long-acting, effects and suppression persist for weeks after the last dose. Use carries serious risks and demands medical oversight and regular bloodwork. Educational information only, not medical advice; 21+.

Clinical readoutAAS · injectable-19nor
Hepatic strainLow
CardiovascularHigh
HPTA suppressionVery high
Half-life
9.5 d
Route
Intramuscular injection
Evidence
B
Active
Clinically long-acting
9.5 d19 d4.1 wk5.4 wk6.8 wk
Illustrative single-compartment washout · each mark = one half-life · t½ ≈ After a single intramuscular injection of nandrolone decanoate, the terminal half-life of nandrolone is approximately 7-12 days (the depot decanoate ester is the rate-limiting step, not nandrolone itself). Serum nandrolone peaks around 30-72 hours post-injection depending on dose (PMID 15713722).
Pharmacology

Mechanism of action

Nandrolone is a synthetic 19-nortestosterone derivative that binds the androgen receptor with high affinity, driving increased muscle protein synthesis, nitrogen retention, and erythropoiesis (red blood cell production). Unlike testosterone, nandrolone is reduced by 5-alpha-reductase to the weaker androgen dihydronandrolone (rather than the more potent DHT), which lowers its relative androgenic (prostate/skin/scalp) activity in androgen-rich tissues; it retains some aromatization to estrogenic metabolites. Like all AAS it exerts negative feedback on the hypothalamic-pituitary-gonadal (HPG) axis, suppressing LH and FSH and thereby endogenous testosterone and spermatogenesis. The decanoate ester is cleaved after intramuscular injection to release free nandrolone gradually.
Kinetics

Pharmacokinetics

Half-life

After a single intramuscular injection of nandrolone decanoate, the terminal half-life of nandrolone is approximately 7-12 days (the depot decanoate ester is the rate-limiting step, not nandrolone itself). Serum nandrolone peaks around 30-72 hours post-injection depending on dose (PMID 15713722).

Active duration

Clinically long-acting; dosing intervals in trials ranged from weekly to every 2-3 weeks. Suppression of the HPG axis and drug effects persist for several weeks after the last injection. Urinary 19-norandrosterone/19-noretiocholanolone metabolites were detectable for up to 6 months after a single 150 mg dose in most subjects (PMID 15713722).

Route

Intramuscular injection (oil depot).

Metabolism & clearance

Hepatic metabolism; nandrolone is metabolized to 19-norandrosterone and 19-noretiocholanolone, which are conjugated and excreted renally in urine. Note: these PK values are provided for monitoring, washout, and clinician discussion only, not for evading drug testing (PMID 15713722).

For monitoring and washout planning, not drug-test evasion.

Reported effects

Physiological & performance effects

  • Increases lean body mass, fat-free mass, and muscle cross-sectional area in controlled trials (e.g., HIV-associated wasting), with further gains when combined with resistance training (PMID 10199766, PMID 15914526).
  • Increases muscle strength in clinical trial populations (PMID 10199766).
  • Increases bone mineral density at the lumbar spine and femoral neck and reduced vertebral fracture rate over 2 years in elderly osteoporotic women (PMID 15972619).
  • Stimulates erythropoiesis, raising hemoglobin/hematocrit; studied as an adjuvant for anemia of chronic kidney disease (PMID 15972619, PMID 12298427, PMID 16281962).
  • Improved self-reported sexual function versus placebo in hypogonadal HIV-infected men in one RCT (PMID 15914526).
Safety

Adverse effects by system

Cardiovascular

Cross-sectional studies of long-term AAS users (including nandrolone) show higher blood pressure, increased interventricular septal and posterior wall thickness (left ventricular hypertrophy), left ventricular diastolic dysfunction, reduced baroreflex sensitivity, sympathetic overactivity, and prolonged/dispersed QT interval; subclinical systolic dysfunction (reduced global longitudinal strain) persists even during off-cycle periods (PMID 29019018, PMID 34209901, PMID 37003371). Nandrolone lowers HDL cholesterol, an adverse atherogenic shift (PMID 12388173).

Hepatic

Nandrolone is a 17-beta-esterified (not 17-alpha-alkylated) steroid and, unlike oral alkylated AAS, has not shown the marked hepatotoxicity of those agents in human studies; overt clinical hepatotoxicity from nandrolone is not well documented in humans. High-dose animal data show elevated liver enzymes (AST, ALT), so liver monitoring remains prudent (PMID 8121303 for the 17-beta ester structure; PMID 26478734 preclinical enzyme elevation).

Endocrine / HPTA

Marked suppression of pituitary gonadotropins (LH and FSH) and consequently endogenous testosterone; a 19-nortestosterone ester reduced sperm to oligozoospermia within about 3 weeks in a controlled male-contraception trial (PMID 1727833). Recovery of the axis after stopping is variable and can be prolonged (PMID 35783920).

Reproductive

Suppression of spermatogenesis (oligozoospermia/azoospermia) via gonadotropin suppression, with reduced testicular function; recovery is variable after cessation (PMID 1727833, PMID 35783920). Testicular atrophy is expected with HPG suppression. In women, virilizing changes may be irreversible (PMID 15972619).

Neuropsychiatric

Nandrolone-specific human psychiatric outcome data are limited. AAS use broadly is associated with mood disturbance, irritability/aggression, and dependence, but high-quality nandrolone-specific human evidence is lacking; this should be regarded as insufficient data, not absence of risk (PMID 35783920 notes AAS class systemic effects).

Renal

No established direct nephrotoxicity in humans; nandrolone has in fact been used as an anti-anemic adjuvant in dialysis patients (PMID 12298427, PMID 16281962). Nandrolone-specific human renal-injury data are lacking, so this is an area of insufficient evidence rather than demonstrated safety.

Hematologic

Stimulates erythropoiesis and raises hemoglobin/hematocrit (therapeutic in anemia but a polycythemia risk in non-anemic users) (PMID 15972619, PMID 12298427). A case report links nandrolone abuse to cerebral venous sinus thrombosis with seizures and neurological deficit, consistent with prothrombotic risk (PMID 29106633).

Dermatologic

Androgenic skin effects (acne, oily skin) can occur, though nandrolone's reduced androgenic potency makes these generally milder than with DHT-forming androgens. In women, virilization including deepening/hoarseness of the voice and increased facial hair was reported in trials (PMID 15972619, PMID 25284341).

Recovery

HPTA suppression & recovery

Suppression: Strong - marked suppression of LH, FSH, endogenous testosterone, and spermatogenesis; because the decanoate ester is long-acting, suppression persists for weeks after the last dose.

Recovery of the hypothalamic-pituitary-gonadal axis after stopping is variable and can be prolonged, depending on duration of use, dose, age, and baseline testicular function; some men do not fully recover spontaneously (PMID 35783920, PMID 1727833). Any recovery approach should be directed by an endocrinologist. Where pharmacologic assistance is considered, only single-SERM approaches are within scope here; dual-SERM protocols are not described. This monograph does not provide a recovery protocol - management is individual and clinician-directed.

Bloodwork & vitals

Monitoring

Recommended labs & checks
Full lipid panel (HDL, LDL, total cholesterol, triglycerides)Complete blood count / hematocrit and hemoglobin (to detect polycythemia)Total and free testosterone, LH, FSH (to document HPG suppression)Liver enzymes (AST, ALT)Blood pressureEstradiol (nandrolone aromatizes to estrogenic metabolites)Prostate-specific antigen (PSA) and prostate assessment in older men before and during androgen exposure

Cadence: Baseline before any exposure, then periodically during use (e.g., every 8-12 weeks is commonly advised for hematocrit, lipids, blood pressure), and again after cessation to track HPG-axis recovery. Cadence should be set by the supervising clinician.

Warning signs — seek care
  • Chest pain, breathlessness, exertional intolerance, or palpitations (possible cardiac strain/arrhythmia)
  • Severe headache, visual changes, focal weakness, or seizure (possible thrombosis/stroke - seek emergency care; case-reported with nandrolone abuse)
  • Leg swelling/pain or sudden shortness of breath (possible venous thrombosis/PE)
  • Markedly rising hematocrit or ruddy complexion, dizziness (polycythemia)
  • Loss of libido, erectile dysfunction, testicular shrinkage, or infertility
  • In women: voice deepening/hoarseness, facial hair, clitoral enlargement (virilization - may be irreversible; stop and seek care)
  • Jaundice, dark urine, right-upper-quadrant pain, or persistent nausea (evaluate liver)
Do not use if

Contraindications

  • Pregnancy and breastfeeding (virilization of a female fetus; contraindicated).
  • Women of childbearing potential and women generally, given the risk of irreversible virilization; explicitly cautioned against in women in the renal-anemia literature due to serious side effects (PMID 16281962, PMID 15972619).
  • Known or suspected androgen-dependent malignancy (e.g., prostate or male breast carcinoma).
  • Pre-existing polycythemia/elevated hematocrit or a personal/family history of thrombosis, given erythrocytosis and case-report thrombotic risk (PMID 29106633).
  • Significant cardiovascular disease, uncontrolled hypertension, dyslipidemia, or heart failure, given adverse lipid and cardiac-structural effects (PMID 12388173, PMID 29019018).
  • Men seeking to preserve fertility, given suppression of spermatogenesis (PMID 1727833, PMID 35783920).
Combinations

Interaction profile

  • MajorWith another anabolic steroid: Additive cardiovascular strain
  • MajorWith a thermogenic stimulant: Additive cardiovascular strain
  • ModerateWith thyroid hormone: Additive cardiovascular strain
  • ModerateWith growth hormone: Additive cardiovascular strain
  • MajorWith another anabolic steroid: Blood / clotting
  • MajorWith a clot-promoting SERM: Blood / clotting
  • ModerateWith an aromatase inhibitor: Hormonal
  • ModerateWith an anabolic steroid: Hormonal
  • ModerateWith another 19-nor (progestogenic) steroid: Hormonal
  • ContraindicatedWith DNP: Additive cardiovascular strain

Check a specific combination in the interaction checker.

Harm reduction

Reducing harm & when to stop

  • This is educational information, not medical advice, and not an endorsement of use; these substances carry serious risks and require a qualified physician and regular bloodwork. 21+ only.
  • Obtain baseline bloodwork before any exposure and monitor periodically: lipid panel, hematocrit/hemoglobin, blood pressure, liver enzymes, and testosterone/LH/FSH; involve a clinician in interpreting results.
  • Because the decanoate ester is long-acting, drug effects and HPG-axis suppression persist for weeks after the last dose - do not assume rapid washout.
  • Stop and seek urgent medical care for warning signs of clotting or cardiac events: severe headache, visual changes, focal weakness, seizure, chest pain, breathlessness, or leg swelling/pain.
  • Rising hematocrit (polycythemia) increases clot risk; if hematocrit climbs, this warrants clinician review and discontinuation.
  • Women should be aware that virilizing effects (voice deepening, facial hair) can be permanent; any such change is a reason to stop and consult a clinician; nandrolone is contraindicated in pregnancy.
  • Suppressed testosterone and fertility may not recover quickly or fully; recovery is individual and should be directed by an endocrinologist. Only single-SERM approaches are within scope here; dual-SERM protocols are not described.
  • No dose here is presented as recommended or optimal; dose ranges cited are those studied in clinical populations and are inseparable from the documented risks.
Evidence

Citations (16)

Every clinical claim above is tied to a primary source. Overall evidence grade B — graded to the best available evidence for its core claims.

  1. 01

    Nandrolone terminal half-life is ~7-12 days after a single IM injection, peaking at 30-72h, with urinary metabolites detectable up to 6 months.

    RCTPharmacokinetic evaluation of three different intramuscular doses of nandrolone decanoate: analysis of serum and urine samples in healthy men.PMID 15713722 ↗

  2. 02

    Nandrolone significantly lowers HDL cholesterol in men (adverse lipid shift), while total/LDL and triglycerides were not adversely affected.

    RCTMetabolic effects of nandrolone decanoate and resistance training in men with HIV.PMID 12388173 ↗

  3. 03

    Nandrolone is a 17-beta-esterified steroid and showed no significant adverse serum lipid change at 100 mg IM weekly for 6 weeks, contrasting with 17-alpha-alkylated oral AAS.

    CohortLack of demonstrated effect of nandrolone on serum lipids.PMID 8121303 ↗

  4. 04

    Nandrolone decanoate increased total body weight, lean body mass, muscle cross-sectional area, and strength in HIV-infected men, augmented by resistance training.

    RCTEffects of pharmacological doses of nandrolone decanoate and progressive resistance training in immunodeficient patients infected with human immunodeficiency virus.PMID 10199766 ↗

  5. 05

    Nandrolone 150 mg biweekly increased lean body mass versus placebo and improved self-reported sexual function in HIV-infected men.

    RCTA randomized, placebo-controlled trial of nandrolone decanoate in human immunodeficiency virus-infected men with mild to moderate weight loss with recombinant human growth hormone as active reference treatment.PMID 15914526 ↗

  6. 06

    Nandrolone decanoate 50 mg every 3 weeks over 2 years increased bone mineral density, hemoglobin, and muscle mass and reduced vertebral fractures in elderly osteoporotic women; virilization side effects (hoarseness, facial hair) were reported.

    RCTThe effect of nandrolone decanoate on bone mineral density, muscle mass, and hemoglobin levels in elderly women with osteoporosis: a double-blind, randomized, placebo-controlled clinical trial.PMID 15972619 ↗

  7. 07

    Evidence for anabolic steroids after hip fracture in older women is insufficient to draw conclusions; reported side effects included hoarseness and increased facial hair (virilization).

    Meta-analysisAnabolic steroids for rehabilitation after hip fracture in older people.PMID 25284341 ↗

  8. 08

    Nandrolone decanoate is used as an anti-anemic adjuvant only in selected male dialysis patients over 50 and should not be given to women due to serious side effects.

    ReviewHormonal adjuvants for the treatment of renal anaemia.PMID 16281962 ↗

  9. 09

    Adjuvant nandrolone decanoate 100 mg IM weekly improved hemoglobin and hematocrit in chronic hemodialysis patients.

    CohortEffects of adjuvant androgen on anemia and nutritional parameters in chronic hemodialysis patients using low-dose recombinant human erythropoietin.PMID 12298427 ↗

  10. 10

    Long-term AAS use in male bodybuilders is associated with higher blood pressure, increased LV wall thickness, autonomic imbalance, and QT prolongation/dispersion.

    CohortLong-term anabolic steroids in male bodybuilders induce cardiovascular structural and autonomic abnormalities.PMID 29019018 ↗

  11. 11

    Long-term AAS use is associated with early LV diastolic dysfunction, increased LV mass index, and reduced baroreflex sensitivity.

    CohortEarly Left Ventricular Diastolic Dysfunction, Reduced Baroreflex Sensitivity, and Cardiac Autonomic Imbalance in Anabolic-Androgenic Steroid Users.PMID 34209901 ↗

  12. 12

    AAS users show reduced global longitudinal strain (subclinical systolic dysfunction) and wall thickening that persists during off-cycle periods.

    CohortChronic anabolic androgenic steroid administration reduces global longitudinal strain among off-cycle bodybuilders.PMID 37003371 ↗

  13. 13

    TRT/AAS suppress spermatogenesis; recovery after cessation is highly variable and sometimes incomplete, and should be managed by a specialist.

    ReviewUnderstanding and managing the suppression of spermatogenesis caused by testosterone replacement therapy (TRT) and anabolic-androgenic steroids (AAS).PMID 35783920 ↗

  14. 14

    A 19-nortestosterone ester markedly suppressed LH and FSH and reduced sperm to oligozoospermia within ~3 weeks in a controlled male-contraception trial.

    RCTDepot gonadotropin-releasing hormone agonist blunts the androgen-induced suppression of spermatogenesis in a clinical trial of male contraception.PMID 1727833 ↗

  15. 15

    Nandrolone abuse has been linked in a case report to cerebral venous sinus thrombosis with seizures and neurological deficit (prothrombotic risk).

    Case reportAnabolic steroid abuse: what shall it profit a man to gain muscle and suffer the loss of his brain?PMID 29106633 ↗

  16. 16

    High-dose nandrolone decanoate elevated liver enzymes (AST, ALT) and altered lipids in rats (preclinical, supports monitoring rather than proving human hepatotoxicity).

    PreclinicalInfluence of nandrolone decanoate administration on serum lipids and liver enzymes in rats.PMID 26478734 ↗

Last reviewed 2026-07-06 · Verified against PubMed · Educational, not medical advice