Surgeons sometimes ask patients to stop testosterone therapy before an elective procedure because of concerns about blood clots, thickened blood, and cardiovascular complications during and after surgery. The picture is more nuanced than a blanket rule, though. Some clinical guidelines actually say testosterone can be continued through surgery, while individual surgeons may still prefer to pause it based on a patient’s specific bloodwork and risk factors.
How Testosterone Affects Your Blood
The core concern is a condition called polycythemia, where your body produces too many red blood cells. Testosterone stimulates red blood cell production, which is why men on testosterone therapy often see their hematocrit (the percentage of blood volume made up of red cells) climb over time. A hematocrit at or above 52% is generally considered polycythemia, and levels above 54% are universally regarded as requiring intervention.
Thicker blood flows more slowly and clots more easily. In a surgical setting, where you’re lying still for extended periods and your body is already in a heightened clotting state from tissue injury, that combination raises the risk of deep vein thrombosis and pulmonary embolism. A study published in the Journal of Urology compared nearly 6,000 men on testosterone who developed polycythemia with a matched group who didn’t. Those with elevated hematocrit had a 35% higher odds of experiencing a major cardiovascular event or blood clot in the first year of therapy.
Cardiovascular Risk During Testosterone Use
Beyond blood thickness, testosterone therapy is linked to a broader increase in cardiovascular events. A large retrospective analysis found that men on testosterone replacement had a major adverse cardiovascular event rate of about 10%, compared to roughly 5.6% in matched controls not using testosterone. After adjusting for differences between the groups, testosterone use was associated with a 27% higher risk of events like heart attack and stroke. The data also showed higher rates of pulmonary embolism, atrial fibrillation, and acute kidney injury in the testosterone group.
Surgery itself is a cardiovascular stress test. Anesthesia, fluid shifts, blood loss, and the inflammatory response all strain the heart and blood vessels. When you layer the cardiovascular burden of testosterone therapy on top of surgical stress, many surgeons and anesthesiologists want to reduce as many modifiable risk factors as possible beforehand.
What Guidelines Actually Say
Here’s where things get less straightforward. Not all professional guidelines agree that testosterone must be stopped. A perioperative management guideline from NHS Scotland explicitly states that testosterone “can be continued in the perioperative period,” noting no strong evidence that it increases venous thromboembolism risk in the same way that estrogen-based hormone therapy does. The American Urological Association’s testosterone deficiency guidelines don’t include a specific directive to stop therapy before surgery.
In practice, whether your surgeon asks you to pause depends on several factors: your current hematocrit level, the type of surgery, how long you’ll be immobilized afterward, and your personal history of clotting or heart problems. Someone with a hematocrit of 48% going in for a minor outpatient procedure faces a very different risk profile than someone at 53% undergoing a lengthy abdominal surgery with days of bed rest.
When Stopping Is More Likely
If your pre-surgical bloodwork shows a hematocrit above 50%, your care team is more likely to want testosterone paused or at least to flag the result for the anesthesiologist. At levels above 54%, some facilities will delay elective procedures until the number comes down. Donating blood or therapeutic phlebotomy (having blood drawn specifically to reduce red cell concentration) is sometimes used to bring hematocrit into a safer range more quickly than simply stopping testosterone and waiting.
The type of testosterone you use also matters for timing. Injectable testosterone, especially longer-acting formulations, stays active in your body for weeks after the last injection. Gels and patches clear your system faster, typically within days. If your surgeon does want testosterone stopped, the timeline will depend on your delivery method. For injections, stopping two to four weeks before surgery is common. For topical preparations, a few days to a week may be sufficient.
What Pausing Feels Like
If you’ve been on testosterone therapy for months or years, even a short break can produce noticeable symptoms. The most common complaints are fatigue, low mood or irritability, decreased libido, and brain fog. These are essentially the same symptoms that led many people to start therapy in the first place, so the return can feel abrupt and frustrating. Most people who started testosterone for diagnosed hypogonadism will feel the gap more sharply than someone whose natural levels were only mildly low.
The good news is these effects are temporary. Once you resume therapy after surgery (typically once your surgeon clears you and your recovery is progressing normally), levels rebuild within days to weeks depending on your formulation. If you’re concerned about the gap, ask your surgeon how soon after the procedure you can restart. For many surgeries, the answer is as soon as you’re eating, moving, and no longer at elevated clotting risk from immobility.
How to Prepare
The most useful thing you can do is get bloodwork, specifically a complete blood count with hematocrit, well before your scheduled procedure. If your hematocrit is in a normal range and your surgery is relatively low-risk, there may be no need to stop at all. Bring your most recent lab results to your pre-surgical appointment so the conversation can be based on your actual numbers rather than a generic policy.
If you are asked to stop, confirm exactly when to take your last dose and when you can restart. Make sure both your prescribing provider (the person managing your testosterone) and your surgical team are aware of each other’s recommendations, since the two don’t always communicate automatically. Planning ahead for the temporary dip in energy and mood, whether that means adjusting your work schedule or lining up extra help during recovery, can make the pause much more manageable.