5 testosterone side effects you must be aware of
Dr. Susan Carter, MD: Endocrinologist & Longevity Expert
Oct 14, 2025 · 15 min read
Testosterone replacement commonly causes a 2–5 mmHg rise in blood pressure, can thicken blood via erythrocytosis (hematocrit may climb to ≥54%), may suppress sperm production and fertility, can increase oily skin/acne, and can worsen obstructive sleep apnea. Tracking blood pressure, hematocrit, and symptoms from day one helps you and your clinician adjust dose or formulation ...