• Standardized visual assessment to quantify the severity of hirsutism in women
• Fulfilling the clinical hyperandrogenism criteria for the diagnosis of Polycystic Ovary Syndrome (PCOS)
• Monitoring therapeutic response to anti-androgen treatments or oral contraceptives

Evaluates terminal (dark, coarse) hair growth across 9 androgen-sensitive body areas. Each area is assigned a score from 0 (no terminal hair) to 4 (extensive visible hair). Maximum score is 36.

• Highly subjective tool with notable inter-observer variability.
• Recent hair removal (shaving, plucking, waxing, laser) drastically masks the true baseline score. Patients should ideally not perform hair removal for 4 weeks prior to assessment.
• Racial and ethnic variations are critical: The normal density of body hair varies wildly by genotype. Standard cutoffs may drastically overdiagnose or underdiagnose hirsutism depending on the patient's heritage.

The original 1961 score included 11 body parts. The "Modified" Ferriman-Gallwey score (mFG), universally used today, removed the lower leg and forearm areas, as hair in those regions is typically independent of androgen levels.

• Calculate total mFG Score.
• Determine clinical hirsutism based on general cutoff (commonly ≥8, though ≥4-6 may be used in certain ethnic populations like East Asian women).
• If positive and accompanying oligo/anovulation or PCO morphology: Meets Rotterdam criteria for PCOS.
• Order biochemical evaluation: Total and Free Testosterone, DHEAS, 17-OH Progesterone (to rule out CAH).
• If virilization is rapid or severe: Immediately screen for androgen-secreting ovarian or adrenal neoplasms.

Developed by Dr. David Ferriman and Dr. J.D. Gallwey in 1961. The current modified version (which dropped 2 regions to establish the 9-region standard) was later refined by Hatch et al. in 1981.