Best serum ever. But... it takes some patience. You have to use the serum faithfully every night after your make up butrrr... then you have some! After a week or 3 you will see a clear difference in the thickness of the hairs and then they become super long! Once the lashes are at strength, you can lower the frequency of use. This is also in the user manual. It's an investment but you'll do it for a whole year! Attention! There's a lot of counterfeiting in circulation so buy it at an authorized revitalash sales point!