I know this is called a lip enhancer, but really, anything that moisturizes your lips well will make them look bigger.  Luckily, this one doesn't sting like some lip plumpers, and it does moisturize well.  I don't usually wear lipstick and just like to wear a good moisturizing chapstick, so this works well for me.  I doubt I would buy it again, though.  It doesn't seem to do anything better than a cheaper chapstick would do.