Since I've started the B-12 I have now have an easily visiable moon on my left thumb when before there wasn't one. The one on my right thumb is very pronounced now when very faint before. The ridges on my nails were not always there and I can't even pinpoint when they began. But I can see up towards the cuticles that the nails are beginning to smooth out. I take this as a good sign. I just never thought of the ridges as being possibly connected. Makes me wonder how long I've been deficient.