Our hair changes as we get older - it's just biology. We've formulated products designed to work with our unique hair biology, for women who know that spirit and confidence don't stop as we get older, and neither should beautiful hair. Hair Biology Thickening Treatment instantly thickens each strand and fights breakage for fuller-looking hair. Free of parabens and dyes and safe for color-treated grey hair. Infused with Biotin. Discover the complete line of age-inspired hair care products from Hair Biology and fall in love with your hair again.