I had several of my nails get ridges in my twenties.  I was told it was because of diet.  I was surviving on pot stickers at the time, odd but they were very convenient in Japan and cheap.  Anyway, the ridges never went away on me.  I don't think they were hormone related on me, as I didn't start experimenting with hormones till I was 30 , but who knows I've always had issues.
Bari Jo