"Extra" caught up with swimwear queen Shay Todd as she debuted her latest collection at Miami Fashion week. Now, Todd is opening up about NIVEA's "Goodbye Cellulite" -- and why it's a must-have for everyone from pin-thin models to the five girls who took NIVEA's "Goodbye Cellulite, Hello Bikini" challenge! Jump in!

Dermatologist Dr. Flor Mayoral weighs in on how the miracle product can give you the perfect beach body, explaining, "It contains L-carnitine -- a basic amino acid that we all need in our body to produce collagen."