Prevage Clinical Lash + Brow Enhancing Serum is a revolutionary product with a clinically documented effect that after only two weeks of use makes lashes and eyebrows look both longer and fuller and gives a healthier impression. Prevage Clinical Lash + Brow Enhancing Serum is a fantastic product that both counteracts delicate eyelashes and reduces wear and tear on the lashes due to age, lack of vitamins and nutrients as well as environmental effects. Apply every night along the lash line.