I've used nail hardening polish, and it really does work. Maybe it will work for growing them longer because they will stay in good condition longer. Also, squeezing your nails and/or buffing them helps with the circulation, which will keep them healthy. Rubbing olive oil on them keeps them healthy too. And pushing the cuticles back (gently), but the most important factor in nail health is the foods you eat. Without nutrients, nothing can thrive. I do all this and everything benefits, hair, skin, the works. I don't need to use the polish now, the natural stuff works just great, and saves money on the polish. Besides, I think buffed nails look nicer than polished, and lasts longer, and it doesn't matter if you don't redo it straight away because it doesn't chip off.