Who this guide is for
This guide is for men on testosterone therapy in any form, injections, capsules, pellets or gel, and for the partners who often notice symptoms first. It sorts warning signs into two groups: the ones that need emergency care now, and the ones that need a call to your provider today. Print it, or save it somewhere you can find it quickly.
You may never need this list. Testosterone does have known risks, though, including blood clots, a rising red cell count and higher blood pressure, and the outcome is better when a warning sign is acted on early. When in doubt, choose the more urgent option.
Call 911 or go to the ER now
These symptoms can signal a blood clot in the lungs, a heart attack, a stroke or another emergency. Do not drive yourself, do not wait to see if it passes, and do not call the clinic first.
- Chest pain, pressure or tightness, especially with sweating, nausea, or pain spreading to the arm, jaw or back
- Sudden shortness of breath, a racing heartbeat, or coughing up blood
- Calf pain or leg swelling together with breathlessness or chest pain
- Stroke signs. MedlinePlus lists sudden numbness or weakness of the face, arm or leg, especially on one side; sudden confusion or trouble speaking; sudden trouble seeing; sudden trouble walking or loss of balance; and a sudden severe headache with no known cause
- An erection lasting longer than four hours, whether or not it is painful
- A severe allergic reaction: swelling of the face, lips or throat, hives with trouble breathing, or fainting
- A very high blood pressure reading with symptoms. The American Heart Association advises calling 911 for a reading higher than 180/120 with chest pain, shortness of breath, back pain, numbness or weakness, vision change or difficulty speaking
- Thoughts of harming yourself. Call or text 988, or call 911 if you are in immediate danger
Tell the emergency team you take testosterone, which product, the dose and when you last took it.
Call your provider today
These signs are not always emergencies, but they should not wait for your next scheduled visit. If you cannot reach your provider the same day, go to urgent care or an emergency room.
- Pain, swelling, warmth or redness in one calf or leg, without breathing trouble. MedlinePlus lists lower leg pain, swelling, warmth or redness among the serious side effects to report right away, and the testosterone cypionate label tells clinicians to evaluate these for a deep vein clot. Same-day assessment matters.
- New breathing pauses, gasping or loud snoring at night that a partner notices, or difficulty breathing during sleep.
- A painful lump or swelling in the breast, or nipple discharge. Breast enlargement can follow treatment, but a new lump needs a look; testosterone is not used in men with breast cancer.
- Swelling of the ankles, feet or hands, or rapid weight gain from fluid.
- Yellowing of the skin or eyes, dark urine, pain in the upper right belly, nausea or vomiting.
- Trouble urinating, a weak stream, sudden urgency or blood in the urine.
- Erections that happen too often or last longer than usual, short of four hours.
- A high home blood pressure reading without symptoms. The AHA advises waiting five minutes and rechecking a reading higher than 180/120; if it is still that high, contact your provider immediately.
- Marked mood changes: new depression, anxiety or agitation that you or people close to you notice.
- A hot, red, painful injection site, drainage, or fever.
- After a pellet insertion: spreading redness, drainage, bleeding through the dressing, or a pellet working its way out of the incision.
If two or more of these show up together, or one is getting worse by the hour, treat it as more urgent rather than less.
Warning signs at a glance
| Symptom | What it can signal | What to do |
|---|---|---|
| Chest pain or pressure | Heart attack, clot in the lungs | 911 |
| Sudden breathlessness | Clot in the lungs, heart rhythm problem | 911 |
| One-sided weakness, slurred speech, sudden severe headache | Stroke | 911 |
| Erection over four hours | Priapism | ER now |
| Calf pain or one-leg swelling, no breathing trouble | Deep vein clot | Same-day call and assessment |
| Breathing pauses at night | Sleep apnea, new or worsened | Call today |
| Painful breast lump or swelling | Breast tissue growth, rarely cancer | Call today |
| Ankle or leg swelling on both sides | Fluid retention | Call today |
| Yellow skin or eyes, dark urine | Liver strain | Call today |
| Reading over 180/120, no symptoms | Severely high blood pressure | Recheck, then call today |
Why these signs matter on testosterone
Each item on the lists ties back to a known effect of testosterone:
- Blood clots. The cypionate label asks clinicians to evaluate leg pain, swelling, warmth and redness for a deep vein clot and sudden shortness of breath for a clot in the lungs. Our page on blood clot warning signs on TRT goes further.
- Thicker blood. Testosterone raises the red cell count, which is why hematocrit is checked on every monitoring panel. Our article on high hematocrit on TRT explains the thresholds.
- Blood pressure. In 2025 the FDA added a blood pressure warning to testosterone products that lacked one. Our article on whether TRT raises blood pressure has the detail.
- Heart rhythm and kidneys. In the TRAVERSE trial, testosterone did not increase major heart events compared with placebo, but atrial fibrillation, acute kidney injury and clots in the lungs were more common in the testosterone group. Our page on whether TRT can cause atrial fibrillation explains what that means for you.
- Breast tissue and erections. The label lists gynecomastia and priapism among possible effects. Our pages on sore nipples on TRT and an erection lasting more than four hours cover each.
What can wait for your next visit
Some effects are worth mentioning but are not urgent: mild acne, oily skin, a little soreness at the injection site that fades within a couple of days, mild fluid retention that comes and goes, or feeling a bit more irritable around injection day. Write them down and bring them up at your follow-up, or send a message if they are getting worse. Several of these hint that a dose is running high; our page on signs your TRT dose is too high explains the pattern.
A preparedness checklist
- Keep a current list of your medicines, with your testosterone product, dose and schedule, in your wallet or phone
- Know the nearest emergency room and urgent care
- Save your clinic’s phone number
- If you have a home blood pressure cuff, know your usual range
- Make sure your partner knows the 911 signs on this page
How Ultimate Male watches for these signs
Prevention is quieter than any emergency. At our San Gabriel and Downey clinics, testosterone treatment is monitored with on-site labs, including hematocrit, PSA and testosterone itself, on the schedule in your written plan, and blood pressure is checked at visits. Your PA-C or MD reviews your history of clots, sleep apnea and heart disease before treatment starts, and adjusts the plan when a number drifts.
For a same-day question during clinic hours, call 626-319-5261. Outside those hours, use urgent care or an emergency department for anything on the lists above.
For routine follow-ups, dose questions or a review of how your testosterone therapy is going, you can book a follow-up visit online.
