Can the hyaluronic acid applied to the skin be absorbed?
Hyaluronic acid, especially its sodium salts, is a very important base moisturizing ingredient in skin care products. It is generally believed that this is because of its strong water absorption, as a hygroscopic agent, can hold a large amount of water. But in fact, hyaluronic acid is also a kind of physiological active substance, which can promote tissue repair, cell protection and immune cell proliferation. So the question is, can the hyaluronic acid (or sodium) applied to the skin be absorbed?
Essendoubi et al published an article in 2016 on Skin Research & Technology, a well-known magazine in the field of dermatology Research Technology, which verified this by using Raman spectroscopy. Apply different molecular weight of hyaluronic acid to the skin surface, then use Raman spectroscopy to see them in which layer of the skin, and finally found that the different molecular weight hyaluronic acid can be absorbed by skin, of course, the whole, high molecular weight (100-1.4 million), molecular weight into the stratum corneum is given priority to, and low molecular weight (20000-300000) into the deeper.
Therefore, although the molecular weight of hyaluronic acid is relatively large, there is a variety of evidence that application on the skin can be absorbed by the skin. So the conventional view that molecules above 500Da cannot be absorbed is wrong, or at least incomplete; Hyaluronic acid not only ACTS as a moisturizer on the surface of the skin, but also may play a physiological role in the skin, such as promoting damage repair, providing cell protection and so on. After being absorbed, hyaluronic acid can be completely metabolized and excreted by the body.