Testosterone injections can make the blood testosterone level look better while sperm production becomes worse. External testosterone suppresses LH and FSH, the pituitary signals needed to maintain high testosterone concentrations inside the testis and support spermatogenesis. The result can be a very low sperm count or azoospermia. This is why current fertility must be discussed before starting testosterone replacement. Many men recover sperm after stopping treatment, but recovery is measured in months, sometimes longer than a year, and it is not guaranteed to return to the previous baseline.

Why does testosterone lower sperm count?

Normal sperm production depends on signals from the pituitary gland: LH stimulates Leydig cells to make testosterone inside the testis, and FSH supports the seminiferous tubules where sperm develop. Testosterone injections, gels or other external testosterone create negative feedback at the hypothalamus and pituitary. LH and FSH fall, intratesticular testosterone drops sharply, and spermatogenesis slows or stops.

The important paradox: a high blood testosterone can coexist with poor sperm production

A serum testosterone result mainly tells you what is circulating in the blood. Sperm production depends on the much higher intratesticular testosterone concentration created under LH stimulation. With injections, blood levels may be normal or high while LH and FSH are suppressed and intratesticular testosterone falls. A “good testosterone number” therefore does not prove that fertility is being preserved.

Can testosterone injections cause azoospermia?

Yes. Testosterone has been deliberately studied as part of male hormonal contraception because it can suppress sperm production. Not every man becomes azoospermic, but the effect can be profound enough that sperm are absent from semen while treatment continues.

Does this mean infertility is permanent?

Usually not, but recovery cannot be promised on a fixed timetable. Data from male hormonal-contraception studies found recovery to a sperm concentration of 20 million/mL in about two-thirds of men within 6 months and about 90% within 12 months after stopping androgen suppression. Men treated clinically with testosterone can differ from research volunteers, especially after long-term use, older age, previous infertility or combined anabolic-steroid exposure. Some take more than a year to recover.

What affects recovery time?

• How long testosterone was used and the dose or formulation.
• Age and baseline testicular function.
• Whether anabolic steroids or other suppressive drugs were also used.
• Whether sperm production was normal before treatment.
• Underlying pituitary, testicular or genetic causes of infertility.

What should you do if you are on testosterone and want a child?

Do not manage the change alone. A male fertility specialist should review why testosterone was prescribed, how long it has been used, current symptoms, semen analysis and hormones. In many men, exogenous testosterone is stopped under medical supervision. The plan must balance fertility, symptoms of hypogonadism and the couple’s timeline.

Which tests are useful?

• Semen analysis to determine whether sperm are present and establish a baseline.
• Morning testosterone, LH and FSH after appropriate clinical review.
• Additional prolactin, estradiol or other endocrine tests when the pattern suggests a specific problem.
• Testicular examination and further male infertility work-up if sperm do not recover as expected.

Are there fertility-friendly alternatives for low testosterone symptoms?

Selected men with functioning testes and pituitary glands may be treated with medicines that stimulate or preserve endogenous hormone production rather than directly replacing testosterone. AUA/ASRM notes that hCG, selective estrogen receptor modulators (SERMs) and aromatase inhibitors can be used in selected infertile men with low testosterone. These are specialist treatments and are not interchangeable with standard TRT.

Can sperm be frozen before starting TRT?

Yes. Men who may want biological children later should discuss fertility before long-term testosterone is started. A baseline semen analysis can show whether sperm are present, and sperm cryopreservation may be sensible before treatment in selected men, especially when fertility is important and future recovery is uncertain.

What if no sperm return after stopping testosterone?

Persistent azoospermia needs a proper infertility evaluation rather than repeated waiting. The doctor will check whether gonadotropins remain suppressed, whether there was pre-existing testicular dysfunction, and whether additional treatment is appropriate. Surgical sperm retrieval is not the first response to recently stopped testosterone if a reversible suppression pattern is still present.

When to see a male fertility specialist

• You are taking testosterone and plan pregnancy now or within the next year.
• Semen analysis shows severe oligozoospermia or azoospermia during or after TRT.
• You stopped testosterone but sperm have not recovered over the expected follow-up period.
• You had fertility problems before starting testosterone.

What to bring for consultation

• Name, dose, formulation and duration of all testosterone products used.
• Any anabolic steroids, bodybuilding drugs or supplements used at the same time.
• Semen analyses before, during or after TRT if available.
• Morning testosterone, LH, FSH and other hormone reports.
• The couple’s fertility timeline and the female partner’s basic fertility evaluation if available.

FAQs

Related reading

• Anabolic Steroids and Male Infertility
• No Sperm in Semen: Can You Still Become a Father?
• Hormonal Tests for Male Infertility
• Semen Analysis Report Explained
• Urologist in Latur

References

• American Urological Association/American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline (2020; Amended 2024) https://www.auanet.org/guidelines-and-quality/guidelines/male-infertility
• European Association of Urology. EAU Guidelines on Sexual and Reproductive Health: Male Infertility. 2026 https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-infertility
• Liu PY, Swerdloff RS, Christenson PD, et al. Rate, extent, and modifiers of spermatogenic recovery after hormonal male contraception: an integrated analysis. Lancet. 2006;367(9520):1412-1420. doi:10.1016/S0140-6736(06)68614-5.
• Brannigan RE, Hermanson L, Kaczmarek J, et al. Updates to Male Infertility: AUA/ASRM Guideline (2024). J Urol. 2024;212(6):789-799. doi:10.1097/JU.0000000000004180.