Short answer: In the 4-month Jatenzo study of 166 men, the most common reactions were headache (4.8%), hematocrit increased (4.8%), hypertension (3.6%), lower HDL cholesterol (3.0%) and nausea (2.4%). The study had no placebo group. Average 24-hour blood pressure rose 4.9/2.5 mm Hg, and 7.2% of men started or increased blood pressure medicine. The current label has no boxed warning.
What Jatenzo is approved for: Jatenzo is approved as testosterone replacement therapy in adult males with low or absent natural testosterone due to primary hypogonadism (testicular failure) or hypogonadotropic hypogonadism (a pituitary or hypothalamus cause). The label says safety and efficacy have not been established in men with "age-related hypogonadism" or in males under 18 (section 1).
Source
JATENZO (testosterone undecanoate) capsules, for oral use, prescribing information and Medication Guide. Tolmar. DailyMed, version published October 15, 2026. DailyMed setid ed7b5d41-7475-4c10-99b9-b62b3434ae60
No. The current Jatenzo label has no boxed warning.
These are the label's own numbers from the Adverse Reactions section. Where the label compares with placebo (a dummy treatment), both columns are shown, so you can see how much more often a reaction happened on Jatenzo.
| Preferred Term | Overall (N = 166) n (%) |
|---|---|
| Headache | 8 (4.8) |
| Hematocrit increased | 8 (4.8) |
| Hypertension | 6 (3.6) |
| High-density lipoprotein decreased | 5 (3.0) |
| Nausea | 4 (2.4) |
166 men took Jatenzo twice daily with morning and evening meals for about 4 months. All started at 237 mg twice daily and were titrated to 158, 198, 316 or 396 mg twice daily. There was no placebo group.
Across all 569 men who took Jatenzo in Phase 2 and 3 trials, reactions in more than 2% were polycythemia, diarrhea, dyspepsia, burping, swelling of the legs, nausea, increased hematocrit, headache, enlarged prostate and hypertension.
Blood pressure: in 135 men with usable 24-hour readings, systolic rose by an average of 4.9 mm Hg and diastolic by 2.5 mm Hg by day 139. In men already on blood pressure medicine, the rise was 5.4/3.2 mm Hg. 12 men (7.2%) started or increased blood pressure medicine.
Heart rate rose by an average of 2.2 beats per minute during the study.
3 of 166 men (1.8%) left the study early because of side effects: rash (1) and headache (2). Hematocrit rises (4.8%) came in the second half of the study and none led to stopping.
PSA rose by an average of 0.2 ng/mL. A rise of at least 1.4 ng/mL or a PSA above 4 ng/mL occurred in 3 men (1.9%). New or worse depression was reported in 2 of 166 (1.2%), and suicidal thoughts in 1 of 569 (0.2%).
The Warnings and Precautions part of the label lists these. Each line gives the label's heading and what it means in plain words.
Polycythemia (high red blood cells). Hematocrit is checked before starting and about every 3 months. A high level may require a lower dose or stopping Jatenzo until it falls; if it rises again after restarting, Jatenzo is stopped for good.
Blood clots. Deep vein thrombosis and pulmonary embolism have been reported with testosterone products. In the TRAVERSE study of a testosterone gel, clots occurred in 1.7% vs 1.2% on placebo. If a clot is suspected, Jatenzo is stopped.
Enlarged prostate and prostate cancer. Men with an enlarged prostate (BPH) may see their symptoms worsen, and androgens may raise prostate cancer risk. The label says to check for prostate cancer before and during treatment.
Blood pressure increases. Jatenzo raised average blood pressure by 4.9/2.5 mm Hg after 4 months, and the label says averages had not leveled off by the end of the trial. Blood pressure is checked periodically, and Jatenzo is not recommended with uncontrolled high blood pressure.
Abuse and testosterone level checks. Testosterone has been abused at higher-than-approved doses, often with other anabolic steroids, which can cause serious heart and mental health problems. If abuse is suspected, testosterone levels are checked.
Not for use in women. Jatenzo is not indicated for women because of a lack of controlled studies and possible masculinizing effects.
Sperm production. Large doses of testosterone can suppress sperm production through feedback on the pituitary, which could lower sperm count.
Liver effects. Long use of high-dose oral 17-alpha-alkyl androgens has been linked to serious liver problems. Jatenzo is not known to cause these, but if signs like jaundice appear, it is stopped while the cause is checked.
Edema (fluid retention). Androgens can cause the body to hold salt and water. Swelling, with or without heart failure, can be serious in people with heart, kidney or liver disease.
Gynecomastia. Breast enlargement may develop and persist.
Sleep apnea. Testosterone may worsen sleep apnea, especially with obesity or chronic lung disease.
Lipid changes. Blood fats can change, which may require a change in cholesterol medicine or stopping testosterone. Lipids are checked periodically, especially after starting.
High calcium. In cancer patients at risk of high calcium, Jatenzo is used with caution and calcium is checked regularly.
Thyroid lab values. Androgens can lower thyroxine-binding globulin and total T4 on lab tests, but free thyroid hormone stays the same and there is no sign of thyroid disease.
Depression and suicide. Depression and suicidal thoughts were reported in Jatenzo trials. The label says to seek medical attention for new or worse depression, suicidal thoughts or behavior, anxiety or other mood changes.
From the Medication Guide that comes with Jatenzo:
Dose Track has a side-effect log. Each entry records the symptom, a severity (none, mild, moderate, severe or life-threatening), the date and an optional note, and can be tied to a specific dose or logged on its own. The history screen shows what you logged over time, which makes it easier to tell your prescriber when a reaction started and whether it is easing. The app records what you enter; it does not judge whether a symptom is serious. For anything on the label's call-your-doctor list, call your doctor.
This page is what the FDA label says, in plain words. It is not medical advice. Follow your prescriber, and ask them or your pharmacist about anything here.