Nandrolone cypionate (also known as nandrolone cyclopentylpropionate) is a synthetic anabolic–androgenic steroid (AAS) of the 19‑nor testosterone (nandrolone) family. It is an esterified form of nandrolone, in which the cyclopentylpropionate (cypionate) ester is attached to the 17β‑hydroxyl group, thereby prolonging its release from intramuscular injection sites.
Chemical Information
| Property | Data |
|---|---|
| IUPAC name | (8R,9S,10R,13S,14S,17S)-13‑methyl‑3‑oxo‑17‑[(cyclopentyl)propionyloxy]‑1,2,6,7,8,9,10,11,12,14‑decahydrocyclopenta$$a$$phenanthrene |
| Synonyms | Nandrolone cypionate, Nandrolone cyclopentylpropionate, 19‑nor‑testosterone 17β‑cypionate |
| Molecular formula | C₂₄H₃₆O₃ |
| Molar mass | 376.55 g·mol⁻¹ |
| CAS number | 797‑83‑9 |
| SMILES | C[C@]12CC[C@H]3C@@HC2CCC1OC(=O)CC5CCCC5 |
| Routes of administration | Intramuscular injection (oil solution) |
Pharmacology
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Mechanism of action – Nandrolone cypionate binds to intracellular androgen receptors, acting as an agonist. After metabolic conversion to the active hormone nandrolone, it exerts anabolic effects (protein synthesis, nitrogen retention) and moderate androgenic effects. The cypionate ester slows hydrolysis, resulting in a prolonged plasma half‑life (approximately 7–10 days) compared with unesterified nandrolone.
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Pharmacokinetics – Following intramuscular injection, the ester is slowly cleaved by esterases, releasing nandrolone into systemic circulation. Peak plasma concentrations are typically reached 2–3 days post‑injection; steady‑state levels are achieved after repeated dosing at intervals of 1–2 weeks.
Medical Uses
Nandrolone cypionate has been employed in clinical settings for:
- Anemia – Stimulation of erythropoiesis in certain chronic anemic conditions.
- Cachexia – Management of severe muscle wasting associated with chronic illness (e.g., AIDS, cancer).
- Osteoporosis – Investigational use to improve bone mineral density owing to its modest estrogenic activity via aromatization of trace amounts of metabolite.
Commercial availability of nandrolone cypionate for therapeutic indications is limited; most clinical use of nandrolone has been via the decanoate ester (e.g., Deca‑Durabolin).
Non‑Medical Use and Abuse
Because of its anabolic properties, nandrolone cypionate has been misused by athletes and bodybuilders to increase muscle mass, strength, and recovery. Its detection in anti‑doping testing relies on mass‑spectrometry techniques targeting the parent compound or characteristic metabolites in urine.
Legal Status
| Jurisdiction | Classification |
|---|---|
| United States | Schedule III controlled substance under the Controlled Substances Act |
| United Kingdom | Class C controlled drug (Misuse of Drugs Act) |
| European Union | Listed under the Anabolic Steroid Control Directive (subject to national controls) |
| World Anti‑Doping Agency (WADA) | Prohibited substance ( anabolic agents ) |
Possession or distribution without a valid prescription is illegal in most countries.
Adverse Effects
Common adverse reactions associated with nandrolone esters, including cypionate, are:
- Androgenic effects – Acne, hirsutism, male pattern baldness, virilization in females.
- Hormonal disturbances – Suppression of endogenous testosterone production, potential for testicular atrophy, and altered luteinizing hormone/follicle‑stimulating hormone (LH/FSH) axis.
- Cardiovascular – Dyslipidemia (decreased HDL‑C, increased LDL‑C), potential hypertension.
- Hepatic – Generally low hepatotoxicity compared with 17α‑alkylated steroids, but rare liver enzyme elevations reported.
- Reproductive – Decreased sperm count, infertility; reversible upon cessation in most cases.
- Other – Edema, mood changes, and in rare cases, erythrocytosis.
Detection in Biological Samples
Standard anti‑doping laboratories employ gas chromatography–mass spectrometry (GC‑MS) or liquid chromatography–tandem mass spectrometry (LC‑MS/MS) to identify nandrolone cypionate or its metabolites (e.g., 19‑norandrosterone) in urine. The World Anti‑Doping Agency sets a urinary threshold of 2 ng/mL for 19‑norandrosterone to distinguish endogenous production from exogenous administration.
References
- World Health Organization, International Non‑Proprietary Names (INN) for pharmaceutical substances, 2022.
- United States Drug Enforcement Administration, Controlled Substances Schedules, 2023.
- M. Kicman, “Pharmacology of anabolic steroids,” British Journal of Pharmacology, vol. 154, no. 3, pp. 502‑511, 2007.
- WADA Technical Documents, Prohibited List and Testing Procedures, 2024.
(All information reflects the state of knowledge up to the date of this entry and is drawn from publicly available, reputable sources.)