My main concern was my eyelashes, so I began to apply castor oil to my upper lash line nightly. At first, I dipped my pinky in the jar and applied the oil sparingly — and I would not recommend doing this. While the formula doesn't sting, the jelly-like consistency made it hard for me to see after applying. So instead, I started using a cotton swab, which was much more effective. (If you really want to nail the application, I suggest buying disposable mascara brushes, Buy It, $5, amazon.com.) I noticed results within a week. Not only were my lashes longer, but they also looked thicker and shinier. My eyelashes started to grow so quickly, in fact, that I now only apply the oil every other day. (Related: The Best Eyelash Growth Serums for Serious Length, According to Customer Reviews)