What are the side effects of TRT?

TRT is generally well tolerated when it is properly monitored, but make no mistake, it is a real medical treatment with real side effects. The big four are thicker blood, acne, fertility suppression and breast tenderness.

Almost all of them are dose-related and manageable, which is the entire reason TRT is meant to be a monitored, blood-tested treatment rather than a prescription you collect and forget. Here is what can happen, and why:

• Thicker blood (raised haematocrit) — testosterone tells your bone marrow to make more red blood cells. Helpful up to a point, risky past it, so your blood count gets checked regularly and the dose trimmed if it climbs too high.
• Acne and oily skin — often early and dose-related; usually settles once the dose is dialled in.
• Reduced fertility and shrinking testicles — the one men most underestimate. External testosterone switches off the signal that drives your own production, and sperm count can crater. Often reversible, but not always, and not fast — see can TRT make you infertile.
• Breast tenderness or swelling — some testosterone converts to oestrogen, and when that runs high, breast tissue can respond.
• Fluid retention — mild puffiness, especially in the first weeks.
• Worse sleep apnoea — worth flagging if you snore heavily or wake unrefreshed.
• Mood or libido swings — usually settle once levels are steady; big swings often mean an injection schedule that is too peaky.
• Gel transfer — testosterone gel can rub off onto a partner or child, so wash your hands and cover the area.

It helps to separate the risks men fear from the ones that actually matter day to day. Older worries about heart attacks have been substantially reassured by recent large trials, and current evidence does not show TRT causing prostate cancer, though your PSA is still watched. The practical things to keep an eye on are haematocrit and fertility, both covered more fully in is TRT safe long term.

The bottom line: TRT done properly, started only after two morning blood tests confirm low testosterone, then monitored for haematocrit, PSA and symptoms, is safe and genuinely life-changing for many men. TRT done casually, from a clinic that never rechecks your bloods or a vial bought online, is where men get into trouble. The side effects are not reasons to avoid it; they are the reasons to do it under supervision.