How Clomiphene Affects LH

Clomiphene is a selective estrogen receptor modulator (SERM) that competitively antagonizes estrogen receptors at the anterior pituitary gland. By blocking estradiol's negative feedback signal, the pituitary increases gonadotropin-releasing hormone (GnRH) sensitivity and releases more LH. This stimulates Leydig cells in the testes to produce testosterone. The effect is dose-dependent: 25-50 mg/day typically raises LH by 50-100% within 2-4 weeks. Clomiphene also has weak estrogenic agonist activity at some tissues, including the liver, which can simultaneously raise SHBG.

At 25 mg/day, LH typically increases by 50-70% from baseline within 2-4 weeks. At 50 mg/day, LH may increase by 70-100% or more. In hypogonadal men, clomiphene raises LH from suppressed levels (below 1.5 IU/L) to mid-normal range (3-8 IU/L) within 4-6 weeks in approximately 73% of responders. The effect is sustained while on therapy but reverses within 2-4 weeks of cessation.

Check LH at baseline before starting clomiphene, then retest at 4-6 weeks into therapy to confirm response. After stopping clomiphene, retest LH at 4-6 weeks post-cessation to confirm the HPTA is self-sustaining without pharmaceutical support. If LH does not rise above 2 IU/L by 4-6 weeks on therapy, consider dose adjustment or alternative approaches.

If LH fails to respond to clomiphene at 50 mg/day after 6 weeks, this suggests either residual exogenous androgen suppression (started PCT too early, compound not fully cleared) or pituitary damage from prolonged AAS use. Consider extending the course, adding HCG to directly stimulate the testes, or referring to endocrinology. Do not exceed 100 mg/day as higher doses increase side effects (visual disturbances, mood changes) without proportional LH benefit.

Further reading: PCT bloodwork: when to test and how to know you have recovered