SHBG (Sex Hormone Binding Globulin)

Advanced wellness

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What it isSHBG is a liver-made protein that binds testosterone and estradiol with high affinity, sequestering them away from tissues. Its level is regulated by insulin, thyroid hormone, estrogen, and liver.

DoesActs as the body's sex hormone buffer — when SHBG goes up, the bound fraction rises and free, active hormone falls.

GoodA mid-range SHBG allows the bound and free fractions to coexist in a healthy balance.

BadLow SHBG signals insulin resistance, fatty liver, or hyperthyroidism — and allows free testosterone to spike high relative to total. High SHBG (common with age, hyperthyroidism, low calorie states) lowers free testosterone despite normal totals.

Standard

Men 10–57 nmol/L; women 18–144 nmol/L.

Optimal

25–50 nmol/L men, 40–80 nmol/L women (narrow target)

Modifiers

Falls with insulin resistance, obesity, exogenous androgens; rises with age, low calorie states, alcoholic liver disease, thyroid hormone, estrogen.

How to optimize

Lifestyle: For low SHBG: weight loss, address insulin resistance. For high SHBG: avoid extreme caloric restriction; resistance training.
Diet: For low SHBG: cut sugar, refined carbs; Mediterranean pattern. For high SHBG: adequate carbs and calories.
Supplements: Boron (5–10mg/day) lowers SHBG modestly; address insulin resistance with berberine, inositol.
Peptides: —
Drugs: —

within Men's Hormones