Important Safety Information for Injectable Testosterone

What is Testosterone Cypionate?

Testosterone cypionate is an injectable form of testosterone used for testosterone replacement therapy (TRT) in men with conditions associated with low or absent natural testosterone production (hypogonadism). It is a long-acting testosterone ester that is administered via intramuscular injection, typically every 1-2 weeks, to maintain stable testosterone levels. Testosterone cypionate is FDA-approved for use in adult males with documented testosterone deficiency.

Important Warning: Cardiovascular and Blood Clot Risk

Testosterone replacement therapy may increase the risk of major adverse cardiovascular events (MACE), including heart attack and stroke. Long-term cardiovascular safety of testosterone therapy has not been fully established. Use with caution in patients with pre-existing cardiovascular disease or risk factors.

Blood clots, including deep vein thrombosis (DVT) and pulmonary embolism (PE), have been reported in patients using testosterone products. Seek immediate medical attention if you experience symptoms such as leg pain, swelling, or shortness of breath.

Who Should Not Use Testosterone Cypionate?

Do not use testosterone cypionate if you:

• Have known or suspected prostate cancer
• Have male breast cancer
• Are allergic to testosterone cypionate or any ingredient in the formulation
• Are female (especially if pregnant or breastfeeding—testosterone causes fetal harm)
• Have serious heart disease, including recent heart attack, heart failure, or severe uncontrolled high blood pressure
• Have serious liver disease
• Have serious kidney disease

Use with caution if you have:

• History of blood clots or clotting disorders
• History of stroke
• Sleep apnea
• Benign prostatic hyperplasia (BPH/enlarged prostate)
• High red blood cell count (polycythemia)
• Diabetes
• Obesity

Warnings and Precautions

1. Cardiovascular RiskTestosterone cypionate may increase the risk of heart attack, stroke, and cardiovascular death. Before starting TRT, discuss your cardiovascular health with your provider. Report any chest pain, shortness of breath, or neurological symptoms immediately.

2. Blood ClotsTestosterone therapy has been associated with venous thromboembolism. Symptoms of blood clots include leg pain, swelling, warmth, or redness (DVT) and sudden shortness of breath or chest pain (PE). Discontinue treatment and seek emergency care if these occur.

3. Polycythemia (Elevated Red Blood Cells)Testosterone can increase red blood cell production, potentially leading to thickened blood and increased clot risk. Your healthcare provider should monitor your hematocrit levels regularly and may need to adjust your dose or temporarily discontinue treatment if levels become elevated.

4. Prostate HealthTestosterone may worsen symptoms of benign prostatic hyperplasia (BPH) and may theoretically increase the risk of prostate cancer, though this remains under investigation. Prostate-specific antigen (PSA) levels should be monitored before and during treatment. Testosterone should not be used in men with known or suspected prostate cancer.

5. Sleep ApneaTestosterone may worsen sleep apnea, particularly in men who are obese or have chronic lung disease. Inform your provider if you have or develop symptoms of sleep apnea.

6. Edema (Fluid Retention)Testosterone can cause fluid and sodium retention. Use with caution if you have heart failure, kidney disease, or liver disease, as edema can worsen these conditions.

7. Liver EffectsWhile oral testosterone formulations have historically been associated with liver toxicity, injectable testosterone cypionate has a better hepatic safety profile. However, liver function should be monitored, particularly with prolonged high-dose use.

8. Decreased Sperm ProductionTestosterone replacement therapy suppresses the body's natural hormone production, including FSH and LH, which can lead to decreased or absent sperm production (azoospermia). This may result in infertility. If fertility is a concern, discuss alternative treatments with your provider.

9. GynecomastiaTestosterone can be converted to estrogen, potentially causing breast enlargement (gynecomastia) or breast tenderness. Report these symptoms to your provider.

10. Mood and Behavioral EffectsTestosterone may cause mood changes, including increased aggression, irritability, depression, or anxiety. Misuse of testosterone can lead to serious psychiatric effects.

Common Side Effects

Side effects may include:

• Injection site reactions (pain, swelling, redness)
• Acne or oily skin
• Increased body or facial hair
• Male pattern baldness
• Mood changes
• Headache
• Breast tenderness or enlargement
• Increased red blood cell count
• Fluid retention
• Changes in libido

Serious Side Effects

Seek immediate medical attention for:

• Chest pain or pressure
• Shortness of breath
• Sudden weakness or numbness, especially on one side of the body
• Difficulty speaking
• Severe headache
• Leg pain, swelling, or redness
• Signs of allergic reaction (rash, hives, swelling, difficulty breathing)
• Prolonged or painful erections lasting more than 4 hours

Drug Interactions

Testosterone cypionate may interact with:

• Insulin and oral diabetes medications – May decrease blood glucose; dose adjustments may be needed
• Blood thinners (anticoagulants) – May alter anticoagulant effects; monitoring required
• Corticosteroids – May increase fluid retention risk
• Other testosterone products – Do not use multiple testosterone formulations simultaneously

Pregnancy and Breastfeeding

Testosterone cypionate is contraindicated in females, especially during pregnancy and breastfeeding. Testosterone causes masculinization of the female fetus and can cause fetal harm. Partners of men using testosterone should avoid contact with application sites if using topical formulations.

Controlled Substance

Testosterone cypionate is a Schedule III controlled substance due to potential for abuse, misuse, and dependence. Use only as prescribed. Misuse can cause serious adverse effects including cardiovascular events, liver damage, and psychiatric effects.

Administration Guidelines

• Administered via intramuscular injection into the gluteal muscle (buttock)
• Typical dosing: every 1-2 weeks as prescribed
• Rotate injection sites to prevent tissue damage
• Use proper sterile technique
• Store at room temperature; protect from light

Monitoring Recommendations

Your healthcare provider should monitor:

• Testosterone levels (to ensure appropriate dosing)
• Hematocrit and hemoglobin (for polycythemia)
• PSA (prostate-specific antigen)
• Lipid profile
• Liver function
• Blood pressure
• Bone density (in long-term use)

When to Seek Emergency Care

Get immediate medical help if you experience:

• Signs of heart attack (chest pain, sweating, arm/jaw pain, shortness of breath)
• Signs of stroke (sudden weakness, slurred speech, vision changes)
• Signs of blood clot (leg pain/swelling, sudden breathing difficulty)
• Severe allergic reaction

Reporting Side Effects

Report side effects to the FDA at www.fda.gov/medwatch or call 1-800-FDA-1088.

Consult your healthcare provider for complete prescribing information about testosterone cypionate.