What is the Free Androgen Index (FAI)?

FAI = (Total Testosterone x 100) / SHBG. Normal in women: below 5 (some labs use below 7 or below 10). FAI above 5-10 in women suggests hyperandrogenism. In men, FAI is less clinically used; free testosterone calculation is preferred.

What conditions raise and lower SHBG?

SHBG increased by: estrogen, thyroid hormone, aging, cirrhosis. SHBG decreased by: insulin, androgens, obesity, hypothyroidism, growth hormone, glucocorticoids. Low SHBG with normal total testosterone raises bioavailable testosterone.

Why is SHBG important in PCOS?

In PCOS, hyperinsulinemia suppresses SHBG, reducing binding capacity and increasing free androgen levels. This amplifies the hyperandrogenic effect even when total testosterone appears only mildly elevated.

Sex Hormone Binding Globulin Calculator

Calculate free androgen index (FAI = total testosterone x 100 / SHBG) for hyperandrogenism assessment. Elevated FAI in women above 5-10 suggests hyperandrogenism. SHBG affected by thyroid, insulin, estrogen, obesity.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.

How to Use

Enter the values for the scenario you are assessing. Calculate free androgen index (FAI = total testosterone x 100 / SHBG) for hyperandrogenism assessment. Elevated FAI in women above 5-10 suggests hyperandrogenism. SHBG affected by thyroid, insulin, estrogen, obesity. Use the shbg / fai result to inform your calculation.

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