The second barrier of the skin, below the horny layer or stratum corneum, consists of so-called tight junctions. During aging, this second barrier is weakened.
Small-molecule hyaluronic acid consists of molecules sized 50 KD, and a smaller, shallow molecular weight guarantees increased skin permeation, can induce genes such as occludin and claudins involved in the formation of tight junctions in the upper part of the epidermis. It ensures that the connective tissue of the skin stores water. This additional hydration makes the skin firmer and more supple while visibly decreasing wrinkles.
The use of small-molecule hyaluronic acid ensures that moisture is stored in the skin for a long time. Image analysis of a skin replica after two months of treatment with a small-molecule hyaluronic acid confirmed the anti-wrinkle activity of this hyaluronic acid. However, it was mainly the deep wrinkles that were decreased.