I'm here to tell you this stuff really works, for me at least. It helps my nails grow quickly. It's an important piece in my self care routine because my nails are thin and break easily. I haven't tried anything similar to compare it to, I've never needed anything else. I'm not sure how it applies under polish, I apply it to clean nails and wait a few hours if I'm going to paint my nails. It does absorb quickly. It has a weird smell, but it's not bad. And the liquid will dry a strange yellow color if it dries on the threads of the bottle. But it helps my nails to grow within days and I am absolutely a repeat buyer.