A strengthening serum for denser hair: Made with 99% ingredients from natural origin, this hair serum enriched with biotin thickens your hair and leaves it denser. After 2 months* of use, hair is denser and hair fiber is strengthened and more resistant! *56 days Biotin, known to improve hair quality: Enriched with biotin and vegetal proteins structurally similar to keratin, this strengthening serum is an ideal ally to achieve denser and thicker hair. The leave-in formula of this hair serum with biotin is particularly pleasant to use and doesn't leave a greasy film on hair. Our strengthening serum has been developed responsibly: WE CARE ABOUT PACKAGING: This serum's bottle contains 30% recycled glass and is made of recyclable glass (verify locally). The cardboard box comes from sustainably managed forests and printed with plant-based inks. WE CARE ABOUT WATER: In order to be water-conscious, we used leave-in formulas that do not need to be rinsed. TEST RESULTS After 28 days, a hairdress