I was so pleased with the difference the eyebrow serum made for my brows that I had canceled my appointment to get eyebrow micro blading done about a year ago. It was actually pretty amazing and made a visible difference. I recently bought my third or fourth eyebrow and eyelash duo and have been using the products for over a year now. I noticed, however, that once in a while, my eyebrows would get flaky like dandruff. Once the flakes went away, I was good as new. A few weeks ago though, my eyebrows became irritated with crusty flakes, like even worse dandruff or cradle cap (if you have ever had a baby you know). I'm so sad that continuous use of this product (which is what they recommend if you want to maintain the growth) caused this, and I have no idea when my eyebrows will heal. The hair is getting thin and you can see the pink, irritated skin if you look closely.