Free vs total testosterone: the ratio that actually predicts symptoms

Two men can both have total testosterone at 550 ng/dL. One feels great. The other has the symptoms of a man with total T at 300. The difference is what's bound and what's free - and unless your provider runs SHBG and calculates free T, you're guessing about the number that matters. Here's how the ratio works, why it shifts, and what to do when total looks fine but free isn't.