Bulgarian Tribulus is a powerful herb that has been shown to positively affect mens health – especially in regards to sexual potency and sperm production. The most powerful of all tribulus is called Bulgarian tribulus - being used for many thousands of years. Tribulus is powerful, and that’s why tribulus effects are quite noticeable. Terrestris tribulus enhances ones libido, energy, and even sleep. As with most things, tribulus side effects can happen, but in most cases in a very positive fashion.