Eyebrows thin over time and can be diminished by over-tweezing and shaping. To add, hair follicles can stop producing hair, eyebrow hair can deteriorate, lighten in color, and decrease in volume and density. This clinically-proven serum is powered by Obagi's innovative NouriPlex™ Technology which features a complex blend of four high-performance ingredients to target the Anagen phase of the brow growth cycle where the eyebrow hair flourishes. Eyebrow enhancing serums are most effective during this phase, usually lasting 30-45 days.