Bosley Defense Thickening Treatment volumizes and thickens normal to fine hair. LifeXtend complex contains Algae Extract which helps reduce the action of D.H.T., a primary cause of thinning hair and hair loss. Biotinyl-GHK helps protect and repair hair follicles. Apple Stem Cell Extract may support healthy hair function. Rice Amino Acids and Vegetable Protein helps fortify and nourish roots. Kelp Extract helps protect from photo-aging, frequent washing and damage due to brushing.