BLUE THERAPY serum 75 ml BLUE THERAPY serum 75 ml by Biotherm is a powerful age-defying serum that helps to reduce the appearance of wrinkles and fine lines, while hydrating and firming the skin. This serum contains powerful active ingredients such as Life Plankton™, which helps to boost skin cell regeneration, and the unique Blue Algae Extract, which helps to improve skin elasticity. It also contains hyaluronic acid, which helps to deeply hydrate the skin. This serum is suitable for all skin types, and it helps to restore the skin's youthful look and feel.