Oral Testosterone for Low T: What Patients Should Know

Kyzatrex is an FDA-approved oral capsule of testosterone undecanoate (a testosterone ester) for adult men with confirmed hypogonadism. The label starting dose is 200 mg twice daily with food. Safety and efficacy have not been established for age-related low testosterone (KYZATREX label).

Testosterone replacement therapy (TRT) is also given as injections, gels, or patches. An oral capsule is another way to take the same class of treatment. Diagnosis still needs symptoms or signs plus two early-morning total testosterone results below 300 ng/dL (AUA 2018). The Kyzatrex label requires two morning testosterone measurements below the normal range before starting.

What is oral testosterone therapy?

Oral TRT is testosterone in capsule form. Kyzatrex is a liquid-filled capsule of testosterone undecanoate. An older alkylated oral androgen, methyltestosterone, was linked to serious liver injury. The AUA says clinicians should not prescribe alkylated oral testosterone (AUA 2018). Kyzatrex is not a 17-alpha-alkyl androgen and "is not known to cause hepatic adverse effects" (KYZATREX label). Cleveland Clinic urologists describe Jatenzo, Tlando, and Kyzatrex as bypassing the liver through the lymphatic system (Cleveland Clinic 2024).

Kyzatrex is indicated for primary hypogonadism (testicular failure) and hypogonadotropic hypogonadism (pituitary or hypothalamic failure). Safety and efficacy in men with "age-related hypogonadism" have not been established (KYZATREX label). The FDA kept that limitation of use on every testosterone product in 2025 (FDA 2025).

What are the practical benefits?

A capsule avoids injections and skin application. There is no gel to transfer to a partner or child. Most doses are twice a day by mouth.

Take it with food. In a food-effect study, breakfasts with 16%, 33%, and 45% fat raised 24-hour testosterone exposure by 37%, 87%, and 94% compared with fasting. The approval trial used meals of any type, and 88% of 139 men (95% CI 82-93%) had a 24-hour average testosterone (Cavg) in the 222-800 ng/dL range at day 90 (KYZATREX label). Cleveland Clinic clinicians say all three current oral products need food to work (Cleveland Clinic 2024).

Those 24-hour averages still include daily peaks. At day 90 the mean Cavg was 393 ng/dL and the mean peak (Cmax) was 852 ng/dL. The prescriber sets the dose from a testosterone draw 3 to 5 hours after the morning dose, at least 7 days after a start or change.

What are the risks?

Kyzatrex raises blood pressure. In the approval study, 24-hour ambulatory monitoring showed mean increases of 1.7/0.6 mm Hg at 4 months and 1.8/0.6 mm Hg at 6 months. In men already on blood pressure medicine, the systolic rise was about 3 mm Hg. Hypertension was reported in 4 of 155 men (2.6%), the only adverse reaction at 2% or more in that 6-month study. The label says it is not recommended in uncontrolled hypertension, and that blood pressure increases can raise cardiovascular risk over time (KYZATREX label). In 2025 the FDA added an increased blood pressure warning to every testosterone product (FDA 2025).

TRAVERSE (NEJM 2023) tested testosterone gel in 5,246 men aged 45-80 with hypogonadism and cardiovascular disease or high cardiovascular risk. Major cardiac events were 7.0% with testosterone and 7.3% with placebo, which met noninferiority. Atrial fibrillation, acute kidney injury, and pulmonary embolism were more common with testosterone (TRAVERSE, NEJM 2023).

Androgens can raise hematocrit (the share of blood made of red cells). The Kyzatrex label says to check hematocrit before starting and about every 3 months, and to stop if it becomes elevated. The AUA treats on-treatment hematocrit at or above 54% as a reason to intervene, with a dose change first (AUA 2018). How high hematocrit is handled on TRT walks through that threshold.

Other labeled effects include fluid retention (edema, and a risk of heart failure if there is already heart, kidney, or liver disease), sleep apnea in men with risk factors, and suppressed sperm production. Kyzatrex may cause azoospermia. The AUA says exogenous testosterone should not be prescribed to men who are currently trying to conceive (AUA 2018); how TRT affects male fertility covers that in more detail. A 12-month open-label study also reported headache, joint pain, diarrhea, higher hemoglobin, anxiety, constipation, peripheral edema, and a rise in PSA.

Who should not take it?

Kyzatrex is contraindicated in men with breast cancer or known or suspected prostate cancer, in pregnant women, and in anyone with a known allergy to the product. It is not recommended when blood pressure is uncontrolled. Do not start testosterone within 3 to 6 months of a heart attack or stroke (AUA 2018).

Oral TRT is a reasonable option to discuss if hypogonadism has already been diagnosed and injections, gels, or patches are a poor fit. A normal testosterone result still needs a search for other causes. Age-related low testosterone remains a limitation of use.

The prescriber chooses the product and the dose. Kyzatrex is not interchangeable with other oral testosterone undecanoate capsules.

Bottom line

Kyzatrex is an oral testosterone capsule for men with confirmed hypogonadism, taken twice daily with food. In the approval trial, 88% of men had a 24-hour average testosterone in the normal range at day 90. It raises blood pressure, can raise hematocrit, and can suppress sperm production. Safety and efficacy have not been established for age-related low testosterone. A licensed clinician reviews labs before prescribing; AlphaMD's TRT page explains how that evaluation works.