SHR # 2410 :: RLRx: The Protein Megalin May More Important Than SHBG When It Comes To Sex Steroid Uptake By Tissue : Ronnie Milo - The medical orthodoxy has promoted the idea that sex steroids bound to sex hormone binding globulin (SHBG) are biologically inactive. Free, unbound hormones are though to have biological significance. Some evidence that hormones like testosterone, bound ti SHBG, appear to have effects on tissue. Now the mechanism responsible for bound sex hormones to produce biological activity in a variety of tissue has been identified. Lrp2 also known as Magalin may actually flip the free-androgen theory on its head and show that the medical orthodoxy has had it exactly opposite of the way it really works! AND Lrp2 has these same effects on vitamin D3 and A and may be at the root of why some people don't see the benefits of supplementation.