The FSH/LH ratio is central to reproductive endocrinology and ovarian reserve assessment.
The FSH/LH ratio is central to reproductive endocrinology and ovarian reserve assessment. An inverted ratio (LH > FSH) is the hallmark of polycystic ovary syndrome. Elevated FSH relative to LH signals declining ovarian reserve — perimenopause, premature ovarian insufficiency, or post-oncological gonadotoxicity.
Low ratio: PCOS (most common). Insulin resistance drives excess androgen production, disrupting the hypothalamic-pituitary-ovarian axis. Obesity amplifies through insulin-driven LH hypersecretion. High ratio: diminished ovarian reserve, perimenopause, primary ovarian insufficiency, Turner syndrome, chemotherapy-induced gonadotoxicity.
PCOS: irregular/absent periods, hirsutism, acne, difficulty conceiving, central weight gain. Low reserve: irregular shortened cycles, reduced flow, hot flashes, sleep disturbance, vaginal dryness, infertility.
PCOS: low-glycaemic diet (see HOMA-IR). Inositol (legumes, whole grains, citrus) has specific PCOS evidence. Low reserve: antioxidant-rich foods, CoQ10 precursors.
PCOS: refined carbohydrates, sugar, dairy (IGF-1 precursors stimulate LH). Soy phytoestrogens in excess.
Educational information only — not a diagnosis. Every Pheno result is interpreted in context and reviewed by a physician.
See all 119 markers we test →