What are the side effects of TRT?

TRT is generally well-tolerated when dosed for replacement (not performance) and monitored with regular bloodwork. Most side effects are predictable, dose-dependent, and manageable. The ones men actually run into break down into a short list.

The common ones

• Elevated hematocrit — testosterone increases red blood cell production. Over 52–54% needs action.
• Elevated estradiol — testosterone aromatizes. High E2 causes water retention, mood swings, nipple sensitivity.
• Acne and oily skin — usually peaks in the first 2–3 months and settles.
• Testicular atrophy and infertility — exogenous testosterone shuts down LH and FSH.
• Mild blood pressure rise — usually from fluid retention and hematocrit.

The less common ones

• Sleep apnea aggravation — TRT can worsen pre-existing OSA.
• Mood instability — usually a sign of estradiol swings or unstable dose timing.
• Hair shedding — only in men genetically predisposed to androgenic alopecia.
• Worsening of pre-existing prostate issues — BPH symptoms can flare, but TRT does not cause prostate cancer.

How most side effects get managed

Most issues resolve with three levers: split the dose into more frequent injections (smoother peaks), control estradiol via dose tuning or low-dose AI, and donate blood every 8–12 weeks if hematocrit climbs. Aggressive AI use is the most common rookie mistake — crashed estradiol feels worse than elevated estradiol.