What happens to sperm and fertility on TRT?
Sperm production drops, often to zero. The American Society for Reproductive Medicine explains that testosterone treatment usually leads to low sperm counts or no sperm in the semen, because the testes need far more testosterone inside them than the blood carries, and outside testosterone shuts that local supply down.
This is the trade-off most worth weighing before you start. The AUA guideline says testosterone should not be given to men who are currently trying to conceive, and men who want children in the next few years usually look at other options first. Our page for men trying to conceive covers those choices.
Recovery after stopping is usual but not instant. In a Lancet analysis of 1,549 healthy men given testosterone-based contraception, sperm concentration returned to 20 million per mL in 67% within 6 months, 90% within 12 months and 100% within 24 months. Those were young volunteers with normal hormones, so men with low testosterone should treat the figures as a guide rather than a promise.
Will my testicles get smaller?
They may. The testosterone cypionate label explains that outside testosterone switches off the pituitary’s LH signal, so the testes make less of their own, and it lists testicular atrophy among adverse reactions reported in men.
Because the cause is a quieted signal rather than damage, it is one of the more manageable downsides. Some men add HCG, which imitates LH, to keep the testes working while on treatment. Our pages on whether testicles shrink on TRT and HCG alongside testosterone therapy explain the options.
What about acne, swelling and blood pressure?
These are common enough to plan for. MedlinePlus lists acne among the usual side effects of testosterone injections, and lists swelling of the hands, feet, ankles or lower legs among the effects to report right away. The same page notes that testosterone can raise blood pressure, which is why it is checked before and during treatment.
| Downside | Can it be managed? | Reversible after stopping? |
|---|---|---|
| Low or absent sperm | HCG can help preserve production in some men | Usually, over months to two years |
| Smaller testicles | HCG can help maintain size | Usually, as the LH signal returns |
| Acne or oily skin | Skin care, dose or schedule changes | Usually |
| Fluid retention | Dose review; extra care with heart, kidney or liver disease | Usually |
| Higher blood pressure | Home readings, dose or form changes | Recheck after stopping |
| Higher hematocrit | Dose change; referral if needed | Usually |
Why does the red blood cell count matter?
Testosterone stimulates red blood cell production, and too many cells thicken the blood. The AUA guideline says a hematocrit of 54% or higher on treatment warrants intervention, starting with a dose adjustment when testosterone levels are high, and recommends checking it every 6 to 12 months.
Clot risk is part of the same conversation. The Endocrine Society’s 2026 statement reports that the TRAVERSE trials found no meaningful rise in heart attack or stroke, but roughly a 50% relative increase in pulmonary embolism and more fractures in treated men. If your number is creeping up, our article on high hematocrit on TRT walks through the usual responses.
Is the ongoing monitoring a downside too?
For many men it is the biggest one in practical terms. Treatment means blood tests for testosterone, hematocrit and PSA, blood pressure checks and follow-up visits for as long as you take it, and the costs of each. Our page on how often you need blood work on TRT lays out the rhythm.
TRT is also open-ended for most men. Stopping is possible, but your own production can take months to restart and the original symptoms tend to return. Our answer on whether TRT is for life explains what a planned stop looks like, and our companion answer on whether TRT is worth it sets these costs against the benefits.
How Ultimate Male weighs the trade-offs with you
At our San Gabriel and Downey clinics, the downsides are part of the first conversation rather than the fine print. Your PA-C or MD reviews your baseline hematocrit, PSA, blood pressure and fertility plans before any decision, and explains which risks apply to you specifically.
If you go ahead, your written plan names the side effects to watch and the dates of your follow-up labs, and your provider adjusts the dose or form if a problem shows up. If the trade-offs look wrong for your situation, that is a valid outcome too. Start with a free 10-minute call, then book a visit to see whether testosterone therapy fits your life.
