(total fucking bullshit)
There are, at present, only 3 supplements I know of which are supported by peer-reviewed research:
BCAA's (Branch Chain Amino Acids)
The other things MAY have some effect, but it has not been proven to the scientific community.
In the case of Tribulus Terrestrus, it's claimed to have a positive effect on testosterone levels. The effect, if any, is severely limited and transitory - sort lived - and hardly of measurable benefit.
If your testosterone levels are low, you need TESTOSTERONE from your doctor - not tribulus.