Management of Hypogonadism with Normal FSH and LH Levels

Diagnostic Confirmation

For patients with low testosterone (100 ng/dL) and normal FSH and LH levels, testosterone replacement therapy is the recommended first-line treatment to restore testosterone levels and alleviate symptoms, as recommended by The Journal of Urology 1, 2
Confirm the diagnosis of hypogonadism with a second morning total testosterone measurement, as a single low reading is insufficient for diagnosis, according to The Journal of Urology 1, 3
Ensure symptoms consistent with testosterone deficiency are present (reduced energy, diminished physical performance, fatigue, depression, reduced motivation, poor concentration, impaired memory, reduced sex drive, erectile dysfunction), as noted by The Journal of Urology 2, 4
Normal FSH and LH with low testosterone indicates secondary (hypogonadotropic) hypogonadism, suggesting a hypothalamic-pituitary issue rather than primary testicular failure, as stated by The Journal of Urology 5

Measure serum prolactin levels to screen for hyperprolactinemia, which is particularly important in secondary hypogonadism, as recommended by The Journal of Urology 6, 5
Consider pituitary MRI if total testosterone is <150 ng/dL with low/normal LH levels, as non-secreting adenomas may be present, according to The Journal of Urology 6
Evaluate for conditions that may cause secondary hypogonadism: obesity, diabetes, pituitary dysfunction, HIV/AIDS, chronic narcotic use, chronic corticosteroid use, as noted by The Journal of Urology 3, 4
Measure serum estradiol if breast symptoms or gynecomastia are present, as recommended by The Journal of Urology 5

For patients wishing to preserve fertility: Consider gonadotropin therapy (combination of hCG and FSH) rather than testosterone therapy, as suggested by The Journal of Urology 6
Selective estrogen receptor modulators may be considered for patients with low/normal LH who wish to preserve fertility, according to The Journal of Urology 5

Aim for testosterone levels in the mid-normal range during treatment, as recommended by European Urology 7
Choice of formulation should consider pharmacokinetics, treatment burden, and cost, according to European Urology 7

Weight loss through low-calorie diets can improve testosterone levels in obese patients with secondary hypogonadism, as noted by European Urology 7
Regular physical activity shows similar benefits, though testosterone increases are typically modest (1-2 nmol/L), according to European Urology 7
Consider combining lifestyle modifications with testosterone therapy for better outcomes in symptomatic patients, as suggested by European Urology 7

The American Urological Association (AUA) explicitly states that clinicians should measure serum luteinizing hormone levels in all patients with low testosterone as a Strong Recommendation (Evidence Level: Grade A) 8, 9

LH/FSH levels distinguish between primary testicular failure (high gonadotropins) and secondary/central hypogonadism (low or inappropriately normal gonadotropins) 8, 9
Low or low-normal LH with low testosterone indicates hypothalamic-pituitary dysfunction, which fundamentally changes management options 10, 11

Serum prolactin must be measured in patients with low testosterone combined with low or low-normal LH levels (Strong Recommendation; Evidence Level: Grade A) 8, 9
Persistently elevated prolactin may indicate pituitary tumors such as prolactinomas, requiring endocrinology referral before initiating testosterone therapy 8, 9
Men with testosterone <150 ng/dL and low/low-normal LH should undergo pituitary MRI regardless of prolactin levels, as non-secreting adenomas may be present 8, 9

Starting testosterone without knowing LH/FSH status can lead to inappropriate treatment that suppresses fertility or misses underlying pituitary pathology 10, 11
Exogenous testosterone provides negative feedback to the hypothalamus and pituitary, suppressing gonadotropin secretion and potentially causing azoospermia 10, 11
In hypogonadotropic hypogonadism (low LH/FSH with low testosterone), gonadotropin therapy (hCG plus FSH) can initiate spermatogenesis and achieve pregnancies, whereas testosterone monotherapy will suppress this 10, 11
Patients with functioning pituitary glands but low testosterone may benefit from SERMs, aromatase inhibitors, or hCG to increase endogenous testosterone production while preserving fertility 10, 11
Skipping LH/FSH testing may result in missing reversible causes of hypogonadism (hyperprolactinemia, pituitary adenomas) or inappropriately suppressing fertility in men with secondary hypogonadism 8, 9, 10, 11