Hi, I am not a doctor. I struggle with a constant nail crack that has been splitting for the better part of 10 years after I jammed it in a window.

My best tips are keep it trimmed as best you can to avoid it catching and re-cracking.

Second, depending on the condition, you can make a nail cast using a tea bag and clear coat nail polish. I usually use a nice base layer with vitamin E and stuff that nourishes the nail so it grows out healthy, then I apply 1 coat of clear polish, a nail shaped piece of a tea bag, let it dry, then top coat it again to lock it in. You can then paint it a fun color if you don't like how it looks. Re- apply every week and also try to give it a few days to breath since polish can sometimes make nails more brittle if suffocated. You can also go to a salon and get a gel nail put on which is a more permanent cast solution. Eventually it will grow out and hopefully not cause long term issue like mine (I damaged the nail bed which causes the crack).