I just rub argon oil into mine every night before I go to bed. I suspect you have dry nails, that will help some. Coconut oil is another one people often recommend.
Also never buff your nails, they'll peel and split like crazy if you do that.
Wear gloves for doing the dishes, nails hate hot water.
A polish can help, but use an acetone free remover and instantly re-oil them when you're done.
I worry about biotin because of beard growth. Apparently it's very good for beards.
Just get a routine going and be patient. I think most women have this issue. My mum's just rescued hers with an oil regime.