Fall's hottest trends are, in a word, huge. From luggage-sized handbags to mile-high heels, big is back—and hair is no exception. But forget the stiff, sticky mess that came with sky-high styles of seasons past—today, big hair is soft, bouncy, and actually brushable. The key is creating volume at the roots. The new crop of volumizers are designed to be spritzed on the scalp, and they're infused with high-tech polymers to prevent flaking and follicle fattening proteins like sweet almond, wheat, and keratin to pump up the volume, without over coating your strands. "Think of them as an invisible scaffold for hair," says hair stylist Oscar Blandi, who suggests flipping your hair upside down and using your fingers to separate sections of hair while blow-drying for maximum body. So if big hair is on your fall agenda, these are the products that can super-size your strands—without blowing through an entire can of hairspray. - Cindy Fedida

Ojon Hydrating Thickening Spray, $30
Jonathan Product Create Root Volume Brushable Lifting Spray, $28
Oscar Blandi No Gravity, $18

I never thought retaining water could be a good thing. But Phyto's new Phytojoba Mask proved me wrong. The deep conditioner helps our strands retain water (and the shine, strength, and vitality that comes with well-moisturized hair) by restructuring the hair's protective layers. Their secret ingredient is jojoba oil. It restores the hair's hydrolipidic film, a layer of fatty acids that prevents water from escaping, and promotes good hydration. Add revitalizing (and delish smelling) sweet orange oil, shine-enhancing angelic extract, and detangling guar gum to the roster, and you've got a luscious smelling conditioner that leaves hair soft and shiny—with zero grease or weight. Immediately after use, my thin, highlighted, porous hair looked vibrant and glossy and bouncy—like it was retaining water, in a good way. - Laura Kenney

Phyto Phytojoba Intense Hydrating Mask, $36