I don't normally write reviews, but I am with these because so many people don't think they glow. I've bought a few packets now and they definitely do. However, they must be exposed to daylight (the sun) in order to glow. Leave them sitting on the window sill for a while and then go into a pitch black room to see them glow. They aren't designed to glow like the glow sticks you see at concerts, so if that's what you're hoping for you will be disappointed. My kids have loads of fun with these and have turned the airing cupboard into their den to take full advantage of their bracelets. Enjoy!