I have mixed feelings about this product. I bought this with the Tarte Lights, Camera, Lashes! mascara (which I love) during a sale. When I use this primer with the Tarte mascara, I don't notice a huge difference from when I don't use the primer. I also find that its white color is difficult to cover -- I have to apply coat after coat of black mascara on top. That said, I tried this under my Maybelline Great Lash (which I don't like) and it made a HUGE difference. It made my lashes longer and fuller and they didn't clump. That was a pleasant surprise, but I still don't think that justifies the price point. Honestly, just invest in a good mascara (by good, I mean a regular mascara that does the job for you) and forget about this pricey, pointless primer.