Belinda Carli
Director, Institute of Personal Care Science (IPCS), Australia

Abstract

As we age, natural stores of hyaluronic acid (HA) decline, resulting in the loss of suppleness and an increase of fine lines and wrinkles. For those trying to defy the visible effects of ageing, there are two options: injectable HA, or less extreme topical applications. This article will take a look at materials used in topical applications to mimic the benefits of HA as well as those that help to stimulate natural HA synthesis, to help restore a more youthful appearance and smoother looking skin.

Hyaluronic acid (HA) is a highly hygroscopic molecule that can attract and bind up to 1000 times its weight in water. It can be found in the stratum corneum, where it keeps older, dead skin cells hydrated for visible softness and suppleness. When the stratum corneum is deficient in HA, it will appear dry, flaky and irregular looking. It is also found in the extracellular matrix of the dermis, where it holds moisture within the matrix and ensures optimum collagen and elastin production. When there is sufficient HA, skin appears plump, firm and hydrated and the dermis is structurally supportive of a smooth epidermal appearance.
HA is naturally found in high quantities in young skin. Approximately one third of HA is recycled in the skin daily (1) – in young skin the degradation/synthesis is balanced and the skin maintains a youthful, supple appearance. However, by the time we turn 25, this balance drops and HA levels in skin start to decline. By the time we turn 40, this imbalance becomes noticeable as fine lines and wrinkles and by the time we turn 50, HA content is around half that of our younger years. The visible result of low HA content is thinner looking skin, not ...