TRT claims from a urology account: what holds up?

What did @socalurologyinstitute actually say?

The creator argued that most men on testosterone replacement therapy do not need to donate blood, and that thicker blood from elevated hematocrit is actually a benefit of TRT, not a problem. The specific thresholds offered: only donate if hemoglobin exceeds 18.5 g/dL or hematocrit exceeds 55%. The framing was pointed, calling blood donation advice from online "testosterone enthusiasts" misguided and potentially harmful to patients donating at normal or mildly elevated levels.

The creator also claimed that "thicker blood" holds more oxygen and improves endurance, positioning erythrocytosis as a feature rather than a side effect of testosterone therapy. That framing is where things get complicated.

Does the science back this up?

Partially, but the pro-erythrocytosis argument is a significant overreach. Yes, testosterone stimulates erythropoiesis through EPO pathways, and some degree of increased red cell mass can improve oxygen-carrying capacity. That much has biological plausibility. But calling it a blanket benefit ignores a serious body of evidence on thrombotic risk.

A 2019 study by Sharma et al. in European Heart Journal found that erythrocytosis from TRT was associated with increased risk of venous thromboembolism. The Endocrine Society's clinical practice guidelines (Bhasin et al., 2018, Journal of Clinical Endocrinology and Metabolism) recommend against allowing hematocrit to rise above 54%, and suggest dose reduction or phlebotomy when it does, not celebration. The creator's threshold of 55% for hematocrit before acting actually sits right at the boundary the Endocrine Society calls a red flag. Calling elevated hematocrit a "benefit" without acknowledging clotting risk is a material omission.

What did they get wrong (or right)?

They got one thing right: routine, reflexive blood donation by every TRT patient is not evidence-based. If hematocrit is normal or mildly elevated, phlebotomy can cause iron deficiency and real anemia. A 2021 review by Bachman et al. in Andrology confirmed that not all TRT patients develop clinically significant erythrocytosis, and blanket donation advice circulating on social media is not grounded in individualized care.

What the creator got wrong is the framing of erythrocytosis as good. "Thicker blood is good" is not a clinical statement supported by hematology literature. Elevated blood viscosity is associated with increased stroke and DVT risk, particularly in men with other cardiovascular risk factors. Presenting this as an endurance benefit without caveat is the kind of thing that sounds reasonable to a fitness audience but could cause real harm to a 55-year-old with metabolic syndrome on TRT. The Endocrine Society's guidelines exist precisely because this tradeoff is not straightforward.

What should you actually know?

If you are on TRT, your hematocrit and hemoglobin should be monitored regularly, typically at 3 and 6 months after starting, then annually. The Bhasin et al. 2018 guidelines recommend holding or reducing testosterone dose, and considering phlebotomy, if hematocrit exceeds 54%. That threshold is not arbitrary. It reflects the point at which viscosity-related risks become clinically meaningful.

The creator's specific numbers (hemoglobin above 18.5, hematocrit above 55) are not far off from standard practice thresholds, but presenting them as the only reason to act, while simultaneously framing high hematocrit as beneficial, sends a mixed message. Your TRT provider should be making these calls based on your full cardiovascular risk profile, not a TikTok comment section. Donating blood is not inherently dangerous for TRT patients, but neither is mild erythrocytosis inherently dangerous. The nuance matters. A sports medicine physician or endocrinologist, not a urologist's social media account, should be guiding individual decisions.