The percent bioavailable testosterone expresses what fraction of your total testosterone is actually accessible to tissues, after accounting for SHBG binding.
A low percentage despite normal total T suggests elevated SHBG is binding too much testosterone. This is common in older men, thyroid dysfunction, and heavy alcohol use, all correctable. A low percentage identifies men who may need SHBG-targeted interventions rather than more testosterone.
Optimal % Testosterone Bioavailable: 40-55 %.
Typically re-tested every 10 weeks.