Testosterone and Fertility: How TRT Affects Sperm Production and What to Do

Written by Adam Maggio | Medically reviewed by Dr. Mitchell Ross, MD, ABAARM

TRT suppresses the HPG axis, reducing LH and FSH, which causes testicular atrophy and dramatically reduces sperm production (often to zero). HCG (500–1000 IU every other day) or clomiphene can preserve or restore fertility. Men wanting children should discuss fertility preservation before starting TRT.

The TRT-Fertility Paradox

One of the most important and frequently overlooked aspects of testosterone replacement therapy is its profound effect on male fertility. While TRT effectively treats the symptoms of hypogonadism, it simultaneously suppresses the hormonal signals that drive sperm production — creating a paradox where treating low testosterone can cause infertility.

How TRT Suppresses Sperm Production

The hypothalamic-pituitary-gonadal (HPG) axis regulates testosterone and sperm production through a feedback loop. When exogenous testosterone is administered, the hypothalamus and pituitary detect elevated testosterone levels and suppress GnRH, LH, and FSH production. Without LH stimulation, testicular testosterone production falls dramatically. Without FSH, Sertoli cell function is impaired. The result: testicular atrophy and azoospermia (zero sperm count) in the majority of men on TRT within 3–6 months.

Recovery After TRT Discontinuation

TRT-induced infertility is generally reversible. After discontinuing TRT, the HPG axis typically recovers within 3–12 months, with sperm production returning to baseline in most men. However, recovery is not guaranteed — older men, those with pre-existing fertility issues, and those who have been on TRT for many years may have prolonged or incomplete recovery.

HCG: Preserving Fertility on TRT

Human Chorionic Gonadotropin (HCG) is a peptide hormone that mimics LH, directly stimulating Leydig cells to produce intratesticular testosterone. When used alongside TRT, HCG maintains intratesticular testosterone levels, preserves testicular size, and maintains sperm production in most men. Typical dosing: 500–1,000 IU subcutaneously every other day, or 1,500 IU three times per week.

Clomiphene as an Alternative

Clomiphene citrate (Clomid) is a selective estrogen receptor modulator (SERM) that blocks estrogen feedback at the hypothalamus and pituitary, causing increased GnRH, LH, and FSH secretion. This stimulates the testes to produce both testosterone and sperm. Clomiphene is often used as an alternative to TRT in men who want to preserve fertility, or as a fertility restoration agent after TRT discontinuation.