Testosterone therapy side effects

Covers the potential short- and long-term side effects of testosterone therapy (TRT), including fertility changes, hematocrit elevation, acne, mood shifts, and cardiovascular risk considerations. Learn what to monitor with labs, what symptoms to watch for, and how to reduce risks while optimizing hormones and performance.

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The essentials for testosterone therapy side effects — then explore the latest posts below.

Unexpected effects of testosterone therapy you should know

Dr. Susan Carter, MD: Endocrinologist & Longevity Expert

Aug 23, 2025 · 15 min read

Testosterone therapy can cause “unexpected” side effects beyond libido and muscle gains, including bone-marrow–driven rises in hemoglobin/hematocrit that can reach erythrocytosis when hematocrit exceeds ~54%, along with water retention, acne, mood changes, and reduced fertility. Here’s what to monitor, why these effects happen, and how to manage them safely with your clinician. “Testosterone can be ...

What you need to know about testosterone replacement therapy risks

Dr. Susan Carter, MD: Endocrinologist & Longevity Expert

Aug 07, 2025 · 14 min read

In men with confirmed hypogonadism (total testosterone below ~350 ng/dL or free testosterone below ~100 pg/mL), properly monitored TRT hasn’t shown a major rise in heart attack or stroke risk in recent trials, but it can increase hematocrit by stimulating red blood cell production and may worsen prostate symptoms or suppress fertility over time. Here’s ...