Sex hormone binding globulin and testosterone in men: What your SHBG levels really mean
Dr. Alexander Grant, MD, PhD: Urologist & Men's Health Advocate
Dec 09, 2025 · 13 min read
SHBG is a liver-made carrier protein that tightly binds roughly 70% of circulating testosterone, so higher SHBG can lower free (bioavailable) testosterone and cause “low T” symptoms even when total testosterone looks normal; adult men typically fall around 13.3–89.5 nmol/L. Understanding where your SHBG sits helps explain what your tissues can actually use—and why treatment ...