Smilax is the name given to a number of different varieties of climbing vines that grow throughout South America, the Caribbean, and parts of North America. The variant known as Smilax medica produces a root that is widely reputed as a highly effective herbal medicine. Smilax is also known as sarsaparilla, which is distinct from the well-known flavoring for root beer; the smilax root is essentially tasteless if consumed in its natural form.

Among the indigenous peoples of South America, smilax was employed in the treatment of headaches, and as a counter to general physical weakness, sexual impotence, joint pain, and skin diseases such as dermatitis. Smilax was later regarded as a powerful blood purifier by European explorers who had contact with native medicines; smilax was particularly renowned as a cure for syphilis. Modern scientific research with respect to smilax have confirmed the presence of saponin, a type of plant steroid, which is believed to be theoretically capable of synthesis by the body into either testosterone or estrogen, the male and female sex hormones. Saponin is also found in the tribulus herb, which is also touted as a strength supplement by various factions of the weight training and body building community.

Smilax also contains various flavanoids, which are phytochemicals with antioxidant properties, substances that protect the body from the actions of free radicals. These radicals are commonly oxygen molecules (O2) that have one or more pairs of electrons absent from their structure, making them chemically unstable. The radicals seek to obtain their absent electrons from otherwise stable cells, rendering that cell unstable and in turn forcing it to "steal" necessary electrons from a neighboring cell, a process that will touch off a chain reaction in a larger group of cells, resulting in permanent damage to the cell structure. Antioxidants act as scavengers among the free radicals they encounter. Through the donation of their own electrons, the antioxidants render the radical neutral.

Smilax became known as a dietary supplement on the basis of the erroneous belief that it would be converted into testosterone within the body. Smilax is marketed extensively in the strength training and bodybuilding community on this premise. There is currently no scientific evidence in support of the theory of testosterone or estrogen conversion; smilax has no known side effects associated with its use.

SEE ALSO Chinese ginseng; Dietary supplements; Ephedra; Herbs.