Well at the risk of going in the opposite direction- I was always told nail polish makes the nails weaker. And geletin actually does nothing for the nails or hair.. Just a good general womans vitamin like at GNC ...
My nails are longer on my left hand that right- I guess its because I do more with my right hand including writing.
What I have found- is rubbing vaseline on the hands- especially around the cuticles etc makes them grow faster-.. You would think it would soften the nail too- but it doesn't, and I have been doing this for years. I rub it on about 30 minutes before bed.