Most male enhancement supplements (MAN-UP, Vig Rx, Ejaculoid, Enzyte, Spartan Blend, Expanzite, etc.) contain herbs (horny goat weed, maca, tribulus, etc.) that have been shown to have strong effects on libido and circulation. You will have to continue taking them for the effects to last. As far as whether or not they are addictive, it really depends on what ingredients are in the product. I recommend researching the individual ingredients that you find on the nutrition label.