👨 Testosterone Therapy Fertility Impact Simulator

Exogenous Testosterone Suppresses LH/FSH Output

Placeholder: external testosterone tricks the pituitary into slowing hormone release.

• Hypothalamus: Feedback sensed at (Placeholder short note)
• LH & FSH: Primary hormones cut (Placeholder short note)
• Weeks: Onset of suppression (Placeholder short note)
• Injection/gel: Common therapy route (Placeholder short note)

How exogenous testosterone signals the brain

Placeholder: circulating testosterone is read as a signal to reduce natural production.

Why fertility is affected early

Placeholder: LH and FSH normally drive testicular sperm production.

HPG Axis Negative Feedback Loop Shuts Down

Placeholder: the hypothalamic-pituitary-gonadal axis quiets its normal pulsatile signaling.

• Reduced: GnRH pulse amplitude (Placeholder short note)
• Near-zero: Pituitary LH output (Placeholder short note)
• Falls sharply: Intratesticular T (Placeholder short note)
• ~3 months: Time to full shutdown (Placeholder short note)

The feedback loop mechanics

Placeholder: high peripheral testosterone dampens GnRH pulsing upstream.

Consequence for local testicular hormone levels

Placeholder: intratesticular testosterone drops despite normal blood levels.

Spermatogenesis Declines, Raising Infertility Risk

Placeholder: sperm production slows as testicular stimulation disappears.

• 3–6 mo: Time to oligospermia (Placeholder short note)
• Up to ~90%: Azoospermia incidence (Placeholder short note)
• Decreases: Testicular volume (Placeholder short note)
• Progressive drop: Sperm count trend (Placeholder short note)

Testicular tissue changes over time

Placeholder: seminiferous tubules shrink without FSH/LH stimulation.

Clinical infertility implications

Placeholder: many men on therapy become temporarily infertile.

Reversibility Timeline After Stopping Therapy

Placeholder: fertility often recovers gradually once therapy is discontinued.

• ~4–12 mo: Median recovery time (Placeholder short note)
• Most patients: Full recovery cases (Placeholder short note)
• Longer duration: Factors slowing recovery (Placeholder short note)
• Uncommon: Rare permanent cases (Placeholder short note)

What drives recovery speed

Placeholder: duration of therapy and age influence recovery pace.

Monitoring recovery

Placeholder: semen analysis tracks the return of sperm production.

hCG and SERMs Help Preserve Fertility

Placeholder: co-therapies can keep testicular signaling active during treatment.

• LH activity: hCG mimics (Placeholder short note)
• Clomiphene/tamoxifen: SERM examples (Placeholder short note)
• Recommended: Sperm banking option (Placeholder short note)
• Before starting therapy: Counseling timing (Placeholder short note)

How hCG co-therapy works

Placeholder: hCG directly stimulates testicular Leydig cells like LH would.

Placeholder: discuss fertility goals with a clinician before starting therapy.

Alternative options for patients

Placeholder: SERMs and sperm banking are common preservation strategies.