Sex Hormone Binding Globulin (SHBG) binds hormones, especially estrogen and testosterone so too rapid destruction or consumption is avoided.
Thus, SHBG stabilize your hormone blood levels to a large extent. So the more hormone you have, the more SHBG you need.
The protein albumin can also bind free hormone for the same biologic reason, preserving hormonal action.
Hormones go to the site of the cells they are destined for, activate the receptors, and then are released back into the blood stream so they can act again. If you have great need for more free hormone, such as a menopausal woman with hot flashes, you need to have a bit less SHBG.
Molecules that are free could also be turned into other types of hormones through metabolism, like the weak estrogens of estrone and estriol. The extent that these conversions are occurring will also be reflected in your need for SHBG.
All the hormones are eventually cleared by bile or excreted into the urine.
Women with elevated SHBG may have hormone imbalance. So the quick answer to how much you need: it’s a trick, it’s complex and a changing amount. But it can be tested, and if you are having your hormones tested, this one needs testing too.