The only PROVEN drug in lowering SHBG is Mesterolone i.e. Proviron.
You are forgetting about DHT, and Winstrol. To be clear, Proviron works to bind to shbg, Stanozolol reduces shbg.
Sex hormone-binding globulin response to the anabolic steroid stanozolol: evidence for its suitability as a biological androgen sensitivity test.
Sinnecker G, Kohler S.
Department of Pediatrics, University of Hamburg, West Germany.
Both the androgen-induced decline in serum sex hormone-binding globulin (SHBG) levels during puberty and the anabolic effect of exogenous testosterone are absent in patients with androgen insensitivity (testicular feminization). To determine whether the androgen-induced decline in serum SHBG could be used as a test of androgen sensitivity, we studied the effect of the anabolic-androgenic steroid stanozolol (17 beta-hydroxy-17 alpha-methyl-5 alpha-androstano-[3,2-c]pyrazol) on serum SHBG in 25 control subjects, 3 patients with complete androgen insensitivity, and 4 patients with partial androgen insensitivity. Stanozolol was administered orally for 3 days (0.2 mg/kg.day); blood samples were taken before and 5, 6, 7, and 8 days after the beginning of the test for measurements of serum SHBG. The lowest value (i.e. the peak response) in each subject was used as the measure of the response to stanozolol. In the control subjects the mean nadir serum SHBG level was 51.6 +/- 5.9% (+/- SD) of the initial value (P less than 0.001). In the 4 patients with partial androgen insensitivity the nadir serum SHBG ranged from 73-89%, and in the 3 patients with complete androgen insensitivity it ranged from 93-97% of the initial value.
Thus, the decrease in serum SHBG after short term administration of stanozolol reflects androgen responsiveness and, thus, may be used to differentiate patients with androgen insensitivity syndromes from those with other causes of male pseudohermaphroditism.
However, just because SHBG is lowered does NOT mean an increase in free testosterone.
This particular study noted a reduction in total testosterone due to mesterolone administration, but no change in free testosterone levels.
The authors concluded that:
"The reduction in total plasma testosterone and the unchanged free testosterone is probably due to reduced testosterone binding to SHBG."
So even though mesterolone competes with test for SHBG binding, the diplaced test is cleared from the system faster, resulting in no net change of free test, since as the authors point out:
"the MCR [metabolic clearance rate] is inversely related to the degree of protein binding."
(1) Acta Endocrinol (Copenh) 1974 Oct;77(2):380-6
The effect of mesterolone administration to normal men on the pituitary-testicular function.
Aakvaag A, Stromme SB.