A couple of years ago I had a customer ask what she could do to strengthen her weak nails that had been caused by medication. For those of you who are interested in the response, it was as follows:
If a medication is causing your weak nails, it’s a sign that you are likely deficient in a protein or mineral internally. The one supplement that has been proven to help is biotin, but you should talk to your doctor about your weak nails and see what (s)he suggests you do to combat them.
Aside from remedying the internal issue, there are several things you can do to try to strengthen them. Make sure you don’t use soaps including alcohol when washing your hands – this dries them out and makes them more brittle. ALWAYS wear gloves when using cleaning products for the same reason. You should also moisturize your nails using a lotion or nail soak – dry nails will chip, crack and break.
When prepping your nails for polish, don’t buff them – that breaks them down. If your cuticles aren’t obnoxiously noticeable, leave them be – they help your nails retain moisture, which equals strength. Also don’t overfile – clip them instead, then file with a fine grit file if needed to even them up.
When polishing your nails, choose a strengthening base coat, then opt for a gel polish (they tend to be thicker) and finish with a top coat. If your nails have obvious ridges, choose a top coat that targets ridges. You can always add a second top coat as well.
Finally, when removing polish, DO NOT pick it off. Use a non-acetone based remover to remove the polish, then moisturize your nails and give them a break from polish for a few days to help them strengthen before applying another polish.