Testosterone Undecanoate (Kyzatrex): Patient Information & Safety Notes
Also known as Kyzatrex, Jatenzo
Other names: kyzatrex, testosterone-undecanoate-oral, jatenzo
Testosterone undecanoate (Kyzatrex) is an FDA-approved oral testosterone ester for male hypogonadism. Unlike injectable testosterone esters, it is taken by mouth twice daily with food. It is a DEA Schedule III controlled substance. Jatenzo is another FDA-approved oral testosterone undecanoate product.
In plain language
What Testosterone Undecanoate is used for
- Male hypogonadism (primary or hypogonadotropic)
- Patients who prefer an oral route over injections or topical gels
Taking this medicine
How it is administered
- Oral capsule (taken with food twice daily)
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Risks and precautions
Risks and warnings
- Erythrocytosis (excess red blood cell production)
- Hypertension (blood pressure increase — FDA black box warning for Jatenzo class)
- Acne, oily skin
- Mood changes, irritability
- Suppression of natural testosterone/sperm production
- Sleep apnea exacerbation
Who should not take it
- Prostate cancer or male breast cancer
- Polycythemia
- Severe untreated sleep apnea
- Pregnancy (absolute — not intended for female use)
Common questions
Patient questions
Is Kyzatrex the same as injectable testosterone?
Kyzatrex contains testosterone undecanoate as an oral capsule — it is taken by mouth twice daily with a meal, while most TRT uses intramuscular or subcutaneous injections of testosterone cypionate or enanthate. Both are FDA-approved Schedule III controlled substances for male hypogonadism. The best formulation depends on individual preference and clinical factors assessed by your provider.
Why must Kyzatrex be taken with food?
Testosterone undecanoate requires dietary fat for optimal absorption through the lymphatic system. Taking it without food significantly reduces blood levels. Your prescribing provider will give specific instructions for meal content and timing.
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This information is educational — not medical advice.
This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.