Revitanail nail strengthener is most probably the best on the market to buy. It does cost alot for a strengthner but it works,so well worth the money!

This is the best nail strengthener out in my opinion . I have super weak nails and this works great and stays on for a few days . Awesome undercoat if you don’t have one

This nail strengthening polish does exactly what it claims – it strengthens your nails & they look amazing. However I’ve found if I put a nail polish colour over the top it bubbles, and then my nails don’t look nice. And it’s quite expensive, so I don’t buy it a lot.