Vertical split in nail

[sleepwouldbenice]

First World problem I know but its really annoying me!
I have a vertical split in my thumb nail which I can't get rid of
About 2 years now
I have tried many times to cut the nail below the split or file it down.
But the split re appears a week or so later
Any suggestions to repair it, or will I have a short thumb nail forever!
TIA 😊

Vitamin D helps strengthen nails. I had this going on with my big toe nail for years until I started taking vitamin D, I’d forgotten all about that until I read your post.

I have this on both thumb nails, apparently ( for me) its a sympton of iron deficiency aneamia and the GP has prescribed iron tablets which I hope will resolve the problem.

Thanks all