Testosterone cypionate
[CAS# 58-20-8]

Identification

• Classification: API >> Hormone and endocrine-regulating drugs >> Androgen and anabolic hormone drugs
• Name: Testosterone cypionate
• Synonyms: Depo-Testosterone; Testosterone cyclopentylpropionate
• Molecular Formula: C₂₇H₄₀O₃
• Molecular Weight: 412.61
• CAS Registry Number: 58-20-8
• EC Number: 200-368-4
• SMILES: C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@@H]2OC(=O)CCC4CCCC4)CCC5=CC(=O)CC[C@]35C

Properties

• Density: 1.1±0.1 g/cm³ Calc.^*
• Boiling point: 525.9±50.0 °C 760 mmHg (Calc.)^*
• Flash point: 223.9±30.2 °C (Calc.)^*
• Index of refraction: 1.546 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07;GHS08 Danger
• Risk Statements: H302-H312-H332-H350-H351-H360-H361-H362
• Safety Statements: P203-P260-P261-P263-P264-P270-P271-P280-P301+P317-P302+P352-P304+P340-P317-P318-P321-P330-P362+P364-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Carcinogenicity	Carc.	2	H351
Reproductive toxicity	Repr.	2	H361
Carcinogenicity	Carc.	1B	H350
Reproductive toxicity	Lact.	-	H362
Reproductive toxicity	Repr.	1A	H360
Acute toxicity	Acute Tox.	4	H302
Reproductive toxicity	Repr.	1B	H360
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332

Discovery and Applications

Testosterone cypionate is a synthetic androgen and anabolic steroid commonly used in medicine for testosterone replacement therapy. It is the cypionate ester of testosterone, chemically modified to prolong the hormone’s half-life and sustain its release when administered intramuscularly. The molecular formula of testosterone cypionate is C₂₇H₄₀O₃.

The compound was developed in the mid-20th century to improve the pharmacokinetic profile of testosterone, which naturally has a short half-life and requires frequent administration. By attaching the cypionate ester, a cyclopentylpropionate group, the compound becomes more lipophilic, allowing it to be slowly released from the intramuscular injection site into systemic circulation over an extended period.

Testosterone cypionate is primarily used to treat male hypogonadism, a condition characterized by low endogenous testosterone production leading to symptoms such as fatigue, decreased libido, loss of muscle mass, and osteoporosis. The drug restores physiological testosterone levels and alleviates these symptoms. It is also employed off-label for other indications including certain types of delayed puberty and transgender hormone therapy.

Pharmacologically, testosterone cypionate acts as an agonist of the androgen receptor, modulating gene expression to produce anabolic and androgenic effects. It promotes the development and maintenance of male secondary sexual characteristics and supports protein synthesis, muscle growth, and bone density. Upon intramuscular injection, the cypionate ester is enzymatically hydrolyzed to release free testosterone.

The drug is usually administered by deep intramuscular injection every one to four weeks, depending on the clinical context and patient response. Testosterone cypionate exhibits a half-life of approximately 8 days, allowing for relatively infrequent dosing compared to non-esterified testosterone.

Common side effects may include injection site pain, increased red blood cell count, acne, and potential exacerbation of prostate disorders. Long-term use requires monitoring of hematocrit, liver function, and prostate-specific antigen levels to detect adverse effects.

Testosterone cypionate is regulated as a controlled substance in many countries due to its potential for misuse and abuse, particularly in sports for performance enhancement.

Analytical methods for testosterone cypionate include high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and immunoassays for therapeutic drug monitoring and doping control.

In summary, testosterone cypionate is a long-acting testosterone ester used primarily for hormone replacement therapy in male hypogonadism. Its esterification prolongs the release and activity of testosterone, improving patient compliance and maintaining stable hormone levels.

References

2024. Updates on Testosterone Deficiency in Men Living With HIV and the Cardiovascular Implications. Current Infectious Disease Reports, 26(11).
DOI: 10.1007/s11908-024-00851-x

2024. Testosterone therapy as a novel approach to the management of cytopenias in myelodysplastic neoplasms: a review of literature and case report. Journal of Cancer Research and Clinical Oncology, 150(8).
DOI: 10.1007/s00432-024-05844-w

2024. Baseline serum testosterone and differential efficacy of bipolar androgen therapy and enzalutamide in the randomized TRANSFORMER trial. Prostate Cancer and Prostatic Diseases, 27(5).
DOI: 10.1038/s41391-024-00844-w