Tribulus has easily done more for the testosterone support supplement market than any other kind of supplement. It's one of the most 'proven' testosterone boosters, forming the basis for most testosterone support formulas, which most companies now market in one or two versions. Strictly in terms of boosting testosterone, it's tribulus doing most of the heavy lifting in those formulas. But in multi-ingredient test boosters, it's hard for users - especially new users - to get a sense of tribulus' effectiveness versus the kitchen sink's worth of other ingredients usually present in those products. Experienced users of test booster formulas know this and many just use straight tribulus for a test boost cycle. NOW Foods Tribulus is a popular choice among them with its 45% extract potency and NOW's unmatched reputation for purity and potency.
NOW Tribulus is also a very good product for first time users of test boosters since it will help them get a sense of what tribulus can do all by itself, before spending a lot more money on more exotic and expensive products.