Hubba, hubba! Get excited! Hubba Brow Brow-Enhancing Serum improves the appearance of brow volume in just 4 weeks* and shows fuller-looking brows at 12 weeks.** The clinically tested, gentle formula, which contains a custom blend of vitamins, plant extracts and rice protein, is suitable for sensitive skin and feels comfortable on brows. Brows look healthier, natural and nourished over time. Plus, the wand features a flexible microbristle tip.