Ridge in nail and it breaks easily. What nail hardener do you recommend?

[Seventimesaday]

I have attached a photo which isn’t brilliant, but there is a ridge down the full length of my nail. It never grows out and as soon as my nail grows past the end of my fingertip, it splits along this ridge and I have to file it short.
It only affects this one nail, all the others grown fine, although at this time of year they do tend to break easily.

Can anyone recommend a nail hardener/ ridge repair kit that really works.
False / gel nails are not an option!

I have this too so hoping someone has some advice. Mine’s been like it for nearly 10 years.

I also have this and have heard its a symptom of psoriasis, so it may be worth looking into that.
Afraid I can't suggest nail hardeners as I've always just kept my nails clipped very short. I do use hand cream a lot so my nails don't dry out so much as they grow.

10 years! Was hoping it was a short term thing!

Following - I've had this for 5 or 6 years! Drives me mad!

Me too! Here for the recommendations.

I have similar nails, always have had. I use Rimmel Nail Nurse which does seem to make them better and stronger. There doesn’t seem to be a cure, I’ve tried everything vitamins, oils etc.
Funnily my toenails don’t have the same problem.
i have heard that using a nail brush cleans the nailbed and helps growth.

I have this too. Currently have biab on my nails. Won't fix the issue but stops it breaking so easily. I've had it years and believe it's due to damage in the nail bed and not fixable. Can't remember who told me this.

I'm afraid it's an age thing!

Cuticle oil helps a little if you are diligent but nothing I’ve tried gets rid of the ridge.

I have it on both thumbs, arrived when I got old and nothing helps so I just keep nails short. I think popping all our tablets out of their foil strips has aggravated them so I tend to wear a flesh-coloured 'rubber hat' on the worse one.