What is primary hypogonadism?
Primary hypogonadism is low testosterone resulting from the testes' inability to produce adequate testosterone, despite normal or elevated hormonal signaling from the pituitary gland.
When the testes fail to produce enough testosterone, the condition is called primary hypogonadism. The problem originates in the testes themselves, not in the brain's signaling system. This distinction is crucial for diagnosis and treatment.
In primary hypogonadism, the pituitary gland sends normal or elevated levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) to the testes. However, the testes do not respond adequately to these signals. Lab work reveals the telltale pattern: low testosterone paired with high LH and FSH levels. The body attempts to compensate by producing more signaling hormones, but the testes cannot deliver the testosterone needed.
This differs from secondary hypogonadism, where the pituitary itself underproduces LH and FSH. In secondary cases, both testosterone and the signaling hormones are low. Testing distinguishes between the two, since LH and FSH levels point to where the problem lies.
Primary hypogonadism can stem from genetic disorders, injury, infection, cancer treatment, or age-related testicular decline. Testosterone replacement therapy providers use these lab patterns to confirm primary hypogonadism and guide treatment decisions. Understanding the cause matters because it affects whether additional interventions or fertility preservation approaches may be needed.