I thought they took about 12-24 hours for them to start working, but who really knows the power of amber! I love DD's necklace, the 2nd night after she started wearing she slept through the night which she hadn't done for months. Although she has only slept through once more since then I still believe it works...I haven't given her panadol or bonjela since she has started wearing it. I can just see her eye teeth at the surface of her top gum so i don't think they are very far from coming through.