Hmm. I've always used both satin and silk scarves interchangeably with no issues so I didn't really pay attention to that. I've made it to WL 3 times using both, they seem to serve the same purpose. These scarves here are very silky and don't suck the moisture out of my hair. I use the shiny side toward my hair and more dull side toward the pillow. I think it helps these to stay on at night instead of sliding off onto the pillow. HTH!