Hair and nail supliment question?

I've been taking a hair and nail supliment for a month now and its working - I’m noticing the difference in the quality of my hair and nails. What’s the ingredient which is probably doing this? Is there a natural source from food which I could take as an alternative?

Thanks

Biotin is plentiful in cooked egg yolk (raw egg whites contain an enzyme that prevents absorption of biotin) as well as tree nuts, liver, soybeans and fish.

Silica is found in alfalfa, avocados, strawberries, onions, cucumbers, and dark green veggies. The herb horsetail (Equisetum arvensa) is also a great source of silica.