Free testosterone

Got “Normal” testosterone on Function Health but still feel off? How to interpret results and plan next steps.

Dr. Susan Carter, MD: Endocrinologist & Longevity Expert

Feb 09, 2026 · 11 min read

A testosterone result can be “normal” and still feel off because testosterone deficiency is diagnosed by symptoms plus consistently low morning total testosterone on repeat testing (often around ~300 ng/dL), and total testosterone can look adequate while free testosterone is low when SHBG is elevated. Here’s how to decide when a repeat draw matters, which ...

How to measure testosterone accurately in men

Dr. Alexander Grant, MD, PhD: Urologist & Men's Health Advocate

Dec 10, 2025 · 13 min read

Accurate testosterone measurement in men requires a morning serum (blood) testosterone test using validated lab methods, confirmed on at least two separate days before diagnosing “low T.” Here’s how timing, test type (total vs free), and common at-home kits can skew results and lead you toward the wrong next step. “If you get testosterone testing ...

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 ...

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Got “Normal” testosterone on Function Health but still feel off? How to interpret results and plan next steps.

How to measure testosterone accurately in men

Sex hormone binding globulin and testosterone in men: What your SHBG levels really mean