Undecylic acid - According to this study, it completely inhibits the function of some fungi at concentrations of 750 µg/mL. However, at that concentration, since the human body contains 5.6L of blood, you would need to take 4.2g of the stuff or 84 pills of Candida Force! That is if I am doing my math right at this late hour...
Caprylic acid - It works. Same ingredient in coconut oil, but more concentrated and w/o the saturated fat. According to this research study it works, as does Grapefruit Seed extract. http://www.ebi.calpoly.edu/senior_projects/Thai%20&Ingnacio_SP.pdf
However, I have been taking them both for months and am still not cured.