I actually use this product for my eyebrows! After about 2 weeks of use, my mom commented on how my eyebrows seem a tad bit darker. I must warn though, to use in sparing amounts! If you pack on the product too much, it may clog pores and cause tiny bumps/pimples. I tried using it on eyelashes at first and I actually got a small pimple on my water line, which was no big deal because it naturally popped itself and caused no big deal. I did also get a few clogged pores on my eyebrows, but when used sparingly, that should not be a problem at all! That being said, I wouldn't recommend using this under your makeup since its an oily, and will mostly likely cause smearing/smudging of mascara/eyeliner. 

I think it works, however it takes a long time for you to see a well enough difference