I use it every morning or night! The sheet is thin and adheres perfectly to my face, so I feel like the serum is soaking into my skin. I also love that it's made of 100% cotton. There's no risk of the serum dripping into the pack if it's too much, so I can use it stress-free while doing housework while using the pack! Once I've used up the sheet, there's still quite a bit of serum left in the box, so I can use it as a cotton pad. Does it have any whitening effects? I feel like maybe, but I'm a little worried that's just because the product name is white. I'll keep using it for a little longer! I don't like packs that claim to be moisturizing because they leave too much moisture on my skin, but this pack has just the right amount of moisture and moisturizes just right, so I love it! It's also great that I can easily find it at a drugstore!