Testosterone Replacement Therapy (TRT) Safety Information
Important safety information for testosterone replacement therapy prescribed through YouthFuel. Read this information carefully before and during treatment.
What Is TRT?
Testosterone Replacement Therapy (TRT) is a medically supervised treatment for men with clinically low testosterone levels (hypogonadism). TRT works by supplementing your body's natural testosterone to restore levels to a healthy, normal range.
YouthFuel prescribes testosterone cypionate, the most commonly used form of injectable testosterone in the United States. It is administered via intramuscular or subcutaneous injection, typically once or twice weekly, depending on your provider's recommendation and your individual needs.
Important Safety Warning
Testosterone is a controlled substance (Schedule III). It should only be used under the supervision of a licensed healthcare provider for a diagnosed medical condition. Misuse or abuse of testosterone can lead to serious cardiovascular events, liver damage, and other adverse effects.
Testosterone therapy may increase the risk of major adverse cardiovascular events (MACE) including heart attack and stroke, particularly in men with pre-existing cardiovascular risk factors. Your provider will assess your cardiovascular risk before prescribing TRT.
Contraindications
Do NOT use testosterone if you:
- Have known or suspected prostate cancer or breast cancer. Testosterone may stimulate the growth of these cancers.
- Are pregnant or may become pregnant. Testosterone is a Category X drug and will cause fetal harm. Women should avoid contact with testosterone products.
- Have a known allergy to testosterone cypionate or any component of the formulation (including cottonseed oil or benzyl alcohol).
- Have severe untreated obstructive sleep apnea.
- Have uncontrolled heart failure (NYHA Class III or IV).
- Have a hematocrit above 54% (polycythemia). Testosterone further increases red blood cell production and can raise the risk of blood clots.
- Are actively trying to conceive. Exogenous testosterone suppresses sperm production and can cause infertility. Discuss fertility preservation with your provider.
Common Side Effects
Many side effects of TRT are manageable and may resolve as your body adjusts. Your provider will monitor for these and adjust your treatment as needed.
Common
- Acne or oily skin
- Injection site pain, redness, or swelling
- Increased red blood cell count (polycythemia)
- Fluid retention and mild swelling
- Mood changes (irritability, anxiety)
- Increased body hair growth
- Scalp hair thinning (in genetically predisposed men)
Less Common
- Breast tenderness or gynecomastia (due to estrogen conversion)
- Testicular atrophy (shrinkage)
- Changes in cholesterol levels
- Sleep disturbances or worsening sleep apnea
- Increased PSA levels
- Changes in libido (increase or decrease)
- Headache
Serious Side Effects
Stop treatment and seek immediate medical attention if you experience:
- Cardiovascular events: Chest pain or pressure, shortness of breath, pain spreading to jaw or left arm, sudden severe headache, confusion, vision changes, numbness or weakness on one side of the body. These may indicate a heart attack or stroke.
- Blood clots (venous thromboembolism): Swelling, pain, warmth, or redness in a leg (deep vein thrombosis) or sudden shortness of breath, chest pain, or coughing up blood (pulmonary embolism).
- Polycythemia: Excessively high red blood cell count can increase the risk of blood clots, stroke, and heart attack. Symptoms may include headache, dizziness, blurred vision, or a ruddy complexion.
- Liver problems: Dark urine, yellowing of skin or eyes, persistent nausea, upper abdominal pain. Although rare with injectable testosterone, liver function should be monitored.
- Severe allergic reaction: Difficulty breathing, swelling of face, lips, tongue, or throat, hives, rapid heartbeat.
- Severe mood changes: Depression, aggression, suicidal thoughts, or other significant behavioral changes. Contact your provider immediately if these occur.
Monitoring Requirements
Regular lab work and check-ins are essential for safe TRT. Your YouthFuel provider will order the following tests at baseline and periodically during treatment:
| Test | Purpose | Frequency |
|---|---|---|
| Total Testosterone | Verify levels are in therapeutic range | Baseline, 6-8 weeks, then every 6-12 months |
| Hematocrit / CBC | Monitor red blood cell count for polycythemia risk | Baseline, 3-6 months, then every 6-12 months |
| PSA | Prostate health screening | Baseline (men over 40), then annually |
| Lipid Panel | Monitor cholesterol and cardiovascular risk | Baseline, then every 6-12 months |
| Liver Function (ALT/AST) | Monitor liver health | Baseline, then annually |
| Estradiol | Monitor estrogen levels (aromatization) | As needed based on symptoms |
| Free Testosterone / SHBG | Assess bioavailable testosterone | Baseline, then as clinically indicated |
Your provider may order additional tests based on your individual health profile. It is critical that you complete all requested lab work on time for your safety.
Drug Interactions
Inform your YouthFuel provider about all medications, supplements, and over-the-counter products you take.
Anticoagulants (Warfarin, Heparin)
Testosterone may enhance the anticoagulant effect, increasing the risk of bleeding. INR monitoring and dose adjustments may be required.
Insulin and Oral Diabetes Medications
Testosterone may improve insulin sensitivity, potentially requiring dose reduction of diabetes medications to avoid hypoglycemia.
Corticosteroids
Concurrent use may increase the risk of edema (fluid retention), especially in patients with heart, liver, or kidney disease.
5-Alpha Reductase Inhibitors (Finasteride, Dutasteride)
These medications block conversion of testosterone to DHT and may be used alongside TRT to manage hair loss or prostate concerns. Discuss with your provider.
Opioids
Long-term opioid use can suppress testosterone. TRT may be appropriate in these cases, but coordination between providers is important.
Fertility Considerations
Important for Men Considering Fatherhood
Exogenous testosterone suppresses your body's natural testosterone production through negative feedback on the hypothalamic-pituitary-gonadal (HPG) axis. This suppression significantly reduces sperm production (spermatogenesis) and can cause temporary or prolonged infertility.
If you are planning to have children now or in the future, discuss this with your provider before starting TRT. Alternatives such as clomiphene citrate (Clomid) or hCG may be considered to maintain fertility while addressing low testosterone symptoms. Sperm banking may also be recommended.
Injection Guidelines
- Inject on the same day(s) each week as prescribed. Consistent timing helps maintain stable hormone levels.
- Common injection sites: the vastus lateralis (outer thigh), ventrogluteal (hip), or deltoid (upper arm) for intramuscular injections. Abdomen or thigh for subcutaneous injections.
- Rotate injection sites to prevent scarring, lipohypertrophy, or injection site reactions.
- Store testosterone cypionate at room temperature (68-77 degrees F / 20-25 degrees C). Do not refrigerate or freeze. Keep away from heat and direct light.
- Use proper sterile technique: clean the injection site with an alcohol swab and use a new, sterile needle for each injection.
- Dispose of used needles and syringes in an FDA-cleared sharps disposal container. Never reuse needles.
- Keep testosterone out of reach of children, women, and pets. Transfer of testosterone through skin contact can cause virilization in women and children.
Questions About Your Treatment?
Contact your YouthFuel care team through your patient portal or reach us directly.
Email: support@youth-fuel.com|Phone: (239) 217-1535
Last updated: March 16, 2026