Sage Advice is a beautiful topper that shifts pinky-red/rose gold/copper/purple/bright green.
It *can* be worn alone, but it's quite sheer so you'll need 3-4 coats to build it up. Pop stick swatches show three coats by itself & one coat over On the Black.
I will say, the colors shifts differ depending on its base color (by itself, the green is brighter & the rose gold pops; over black, the purple is more prominent.)
I use high-quality & highly saturated pigments in my products, so staining is possible. It’s always advisable to apply a worthy base coat, especially under darker colored polishes. I recommend Take Your Base protective base coat.