What are the warning signs in your leg?
A clot in a deep leg vein, called a deep vein thrombosis (DVT), usually shows up on one side. MedlinePlus lists the common signs as warmth and tenderness over the vein, pain or swelling in the affected part of the body, and skin redness.
The pattern matters more than any single symptom. A calf or thigh that is newly swollen compared with the other leg, feels warm, aches when you stand or walk, or looks red or darker is worth a same-day call. Testosterone labels ask clinicians to evaluate exactly these signs: pain, swelling, warmth and redness in the lower leg.
What are the warning signs in your chest?
A clot that breaks loose and lodges in the lungs is a pulmonary embolism, and it is an emergency. MedlinePlus lists these symptoms:
- Shortness of breath or rapid breathing
- Chest pain or discomfort that usually gets worse when you cough or breathe deeply
- A faster heart rate
- Coughing up blood
- Very low blood pressure, lightheadedness or fainting
If you have any of these, call 911 or go to the nearest emergency room. Do not wait to call the clinic or book a visit.
How much does testosterone raise the risk?
Somewhat, and the absolute numbers are small. The AndroGel 1.62% label reports results from TRAVERSE, a large trial in men aged 45 to 80 with heart disease or high cardiovascular risk:
| Event in TRAVERSE | Testosterone | Placebo |
|---|---|---|
| Any venous thromboembolism | 1.7% | 1.2% |
| Pulmonary embolism | 0.9% | 0.5% |
| Deep vein thrombosis | 0.6% | 0.5% |
The Endocrine Society’s 2026 statement describes that as roughly a 50% relative increase in pulmonary embolism, even though heart attacks and strokes did not meaningfully rise. The same label notes that a higher red blood cell mass may increase clot risk, one reason hematocrit is tracked on treatment.
Which risk factors raise the odds while you are on TRT?
The usual clot risks still apply, and they stack with testosterone. The NHLBI lists, among others:
- A past blood clot or a known clotting disorder
- Surgery, with the highest risk in the first three months afterward
- Long periods without moving, including flights over four hours
- Cancer and its treatments
- Obesity, heart conditions, kidney disease and older age
- A family history of clots
The Endocrine Society guideline lists thrombophilia and an elevated hematocrit among reasons not to start testosterone. Our page for men with a history of blood clots explains how that review works, and our page on the hematocrit blood test covers the number that ties testosterone to clot risk.
Should you pause TRT before surgery or a long trip?
Sometimes. Surgery is a well-known clot trigger, so tell your surgeon and the clinic early about any planned procedure. Whether to pause, and for how long, depends on the operation and your own risks; our page on stopping TRT before surgery explains the usual approach. For flights, moving your legs and staying hydrated matter whether or not you are on testosterone.
How Ultimate Male screens for clot risk
Before anyone starts treatment, your provider asks about past clots, family history, recent surgery and travel, and the TRT pre-screening panel includes a complete blood count with hematocrit. Those questions come back at follow-up visits, along with repeat labs, so a rising hematocrit or a new risk factor is caught early.
If you are on testosterone now and notice one-sided leg swelling that is not an emergency, call the clinic the same day. For more on how treatment is monitored, see testosterone therapy at Ultimate Male or read about the FDA’s clot warning on testosterone.
