Testosterone is essential inside the testes for normal sperm production, but taking testosterone from outside the body can do the opposite of what many men expect: it can sharply reduce sperm count or stop sperm production. Exogenous testosterone suppresses the pituitary hormones LH and FSH that normally stimulate the testes. Therefore, standard testosterone replacement therapy is generally avoided in men who are currently trying to conceive. Low testosterone and infertility should be evaluated together because treatment depends on whether the problem is testicular, pituitary/hormonal, metabolic, medication-related or another fertility condition.

How testosterone normally supports sperm production

The testes perform two linked but different jobs. Leydig cells produce testosterone under LH stimulation. Sertoli cells support sperm production under FSH and high local intratesticular testosterone. A normal blood testosterone level does not by itself prove that sperm production is normal, and a low sperm count does not always mean blood testosterone is low.

Why testosterone injections or gels can reduce sperm count

When testosterone enters the bloodstream from an injection, gel or other external preparation, the brain senses adequate androgen and reduces GnRH, LH and FSH output. Intratesticular testosterone can then fall dramatically, even if the blood testosterone looks normal or high. Spermatogenesis may slow or stop.

Can a man have low testosterone and still preserve fertility?

Yes. The correct approach depends on the cause of hypogonadism and the fertility timeline. In selected men with secondary hypogonadism, medicines that stimulate the body’s own gonadotropin pathway may be considered rather than direct testosterone replacement. These treatments require specialist assessment and are not suitable for every cause of low testosterone.

Tests when low testosterone and infertility occur together

• At least one properly performed semen analysis; repeat testing is often needed if abnormal.
• Morning total testosterone, repeated if low.
• LH and FSH.
• Prolactin when indicated.
• SHBG/free testosterone in selected cases.
• Clinical examination for testicular size, varicocele and genital tract abnormalities.
• Genetic testing in severe oligospermia or azoospermia when indicated.
• Partner evaluation in parallel because fertility is a couple-level issue.

The hormone pattern can change the fertility plan

Low testosterone with high LH/FSH points more toward primary testicular failure. Low testosterone with low or inappropriately normal LH/FSH points more toward hypothalamic-pituitary suppression. That distinction matters because selected men with secondary hypogonadism may be candidates for fertility-preserving stimulation of the testes, whereas exogenous testosterone suppresses the same LH/FSH pathway.

If future fatherhood matters but is not immediate, it can be useful to discuss a baseline semen analysis and, in selected situations, sperm banking before long-term hormone treatment. Pre-treatment fertility should not be assumed from age, libido or a normal-looking testosterone result alone.

If you already used TRT and now want a child

Do not panic, but do not assume fertility will recover immediately. A fertility-focused andrology review can document semen status, gonadotropins and testosterone and decide whether observation, cessation of exogenous testosterone, medical stimulation or assisted reproductive strategies are appropriate.

• Tell the doctor exactly what product, dose and duration you used.
• Mention anabolic steroids or gym injections as well as prescribed TRT.
• Do not add multiple hormonal medicines on your own; they can make interpretation and recovery more difficult.

Can testosterone improve fertility when testosterone is low?

Direct testosterone replacement is usually the wrong treatment when conception is the immediate goal. The exception is not “low testosterone means take testosterone”; the exception is that some specific endocrine disorders can be treated with gonadotropin-based or other fertility-preserving approaches under specialist care.

When to see an andrologist or fertility specialist

• Trying to conceive for 12 months without pregnancy, or earlier when the female partner is older or there are known risk factors.
• Azoospermia or very low sperm count.
• History of undescended testis, testicular injury, chemotherapy or pelvic surgery.
• Use of TRT or anabolic steroids with fertility plans.
• Low testosterone with low/normal LH and FSH, headaches or visual symptoms suggesting a pituitary cause.

Fertility consultation checklist

Bring these if available:

• One or preferably two semen analysis reports if already done.
• Morning testosterone, LH, FSH, prolactin and SHBG/free testosterone if available.
• Scrotal ultrasound if previously advised.
• Full list of TRT, anabolic steroids, fertility supplements and other medicines.
• Previous fertility treatment records.
• Partner’s basic fertility evaluation if available.

FAQs

Related reading

• Testosterone Replacement Therapy Explained
• Risks of Testosterone Therapy
• Low Testosterone in Men: Symptoms and Treatment
• Male Infertility: Causes, Tests and Treatment
• Semen Analysis Explained
• Low Semen Volume: Causes and Treatment
• Strength Training and Testosterone
• Vitamin D and Testosterone
• Urologist in Latur

References

• European Association of Urology. Guidelines on Sexual and Reproductive Health (2026) https://uroweb.org/guidelines/sexual-and-reproductive-health
• American Urological Association / American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men (2020; amended 2024) https://www.auanet.org/guidelines-and-quality/guidelines/male-infertility
• American Urological Association. Evaluation and Management of Testosterone Deficiency https://www.auanet.org/guidelines-and-quality/guidelines/testosterone-deficiency-guideline
• Endocrine Society. Testosterone Therapy for Hypogonadism Guideline Resources https://www.endocrine.org/clinical-practice-guidelines/testosterone-therapy