It worked well for me. A little too well, actually.
Its a natural and ancient Chinese product, there's a lead time of 2 weeks before the effect kicks in, and then only a little is needed to keep the effect going.
In Australia, Coles sells a proprietary mix called Horny Goat Weed Plus for about $30 for 60 tabs, with each tablet having Igm of Horny Goat Weed Extract, 1gm of Terrestris tribulus, plus a bit of ginseng and guarana. This is quite a dose, and made the packet good value for money. 1/2 a tab every 2 days was enough to make a noticeable difference for me, and in fact I stopped using it because it made me horny to the point where I was irritated and having to wank 3 or 4 times a day just to deal with it. Enough. Some of us have lives to lead!
I think if your testoterone levels are fine, it may be redundant. But it's a nice pill if you have a sex party coming up and a lot of folks to "deal" with...