Poor nail strength is a complex issue that combines diet, genetics, and the presence or absence of certain diseases. There are no methods that have been thoroughly studied to strengthen nails that I could recommend. Chemical nail strengtheners (like the ones that come in the nail polish bottle) are probably fine to use if you'd like. The nail itself is not living tissue, so permanent damage is unlikely as long as you avoid getting the chemicals on your fingers themselves. Just make sure to ask you primary care physician
first. If you feel you are having some sort of reaction to the material (rash or blisters on your fingers), make sure to stop you treatments right away and call your doctor
. My suggestion is that you pose this question to your primary care physician. He or she can give you the most sound advice while taking into account your own past medical history including other medications you are taking and allergies you may or may not have. It is possible that if your problem is severe enough, that your doctor may refer you to a dermatologist
that can take a more comprehensive look at your nails and recommend a more advanced treatment.