I started taking this in December of last year...
Around mid January I went to the doc and, among other things, got my testosterone checked.
Total testosterone was 910. For a 38 year old, that's pretty high. Unfortunately, I didn't have it measured before I started taking the stuff so I can't say definitively that it works, but I did notice my voice got deeper, my dikk got harder, and I started getting back acne shortly after taking it so it probably works.