Hyaluronan, or HA, or ultimately known as hyaluronic acid, is a non-sulfated glycosaminoglycan molecule that is found primarily in connective tissues, like the dermis and epidermis. To put it simply, hyaluronic acid is a molecule, produced naturally by your body, that is found mainly in your skin. Actually, over 50% of your body’s total HA is found in your skin! Hyaluronic acid also works hand in hand with collagen proteins, as HA is also found in joints and skeletal tissues, helping with the retention of collagen. Hyaluronic acid has been shown to improve moisture retention in the skin, alleviate wrinkles, improve joint pains, but more on that later…
The HA molecule is found predominantly in the skin, specifically the dermis and epidermis. The epidermis is the outer layer of skin, while the dermis is the layer of skin that’s beneath the epidermis. In these layers of skin, HA helps with regulation of water balance in the connective tissues. However, as you age, the concentration of HA molecules in the epidermis declines. And because the epidermis loses HA molecules, which is key to water retention, this results in a loss of skin moisture. Furthermore, as you age, HA becomes less viable and effective in the dermis layer of the skin. Thus, as HA efficiency declines in the dermis, this causes skin dehydration and a loss of elasticity. With the combined detriments mentioned above, this results in the appearance of dry, aged skin.
However, not all is a lost, as there are many hyaluronic acid supplements available, both oral and topical. In addition to supplements, hyaluronic acid is naturally found in foods, such as chicken bone broth and beef bone broth, which are also a great source of collagen, amino acids, and other beneficial compounds. Speaking of benefits, hyaluronic acid has numerous benefits beyond improving our skin health.
Benefits of Hyaluronic Acid
Improve Skin Hydration
One of the main factors in maintaining youthful skin is water retention and skin hydration. As we age, our skin cell’s ability to hold water diminishes, and that plays a part in dry skin and, ultimately, aged skin. As explained above, the reduction of HA and its efficiency in the dermis/epidermis contributes to the decrease in skin hydration. By applying topical HA cream or ingesting HA supplements, studies have shown that there is an immediate improvement in the appearance of skin hydration (1). As subjects continued to use hyaluronic acid, studies showed a significant improvement in actual skin hydration (3, 4). This can be due to the re-amplification of hyaluronic acid molecules present in the dermis and epidermis.
Improve Joint Health
Although hyaluronic acid is found predominantly in the skin, it is also found in joints, connective tissues, tendons, etc. When talking about joints, we must bring up synovial fluid, which is the fluid found in joints that helps to reduce friction between cartilage and joints. Studies have shown that oral HA has proven to help reduce joint pain, in specific, when it is associated with joint aggravation through friction (10). Going one step further, articular hyaline cartilage provides cushioning between your bones and joints, reducing friction and inflammation. Advancements in medicine have proven that HA injections can provide relief and help improve osteoarthritis of the knee through reparations and aid from hyaluronic acid (11, 12).
As mentioned above, with the progression of age, our skin isn’t able to hold onto water the way it was used to. This causes dry skin, as well as, eventually, causing wrinkles in the skin. However, studies have shown that when hyaluronic acid is taken orally, there is a significant reduction in wrinkle depth (6, 7). Topical HA is not as effective as penetrating the skin’s multiple layers, and it doesn’t allow for as effective skin improvements. However, studies have shown that a low molecular weight hyaluronic acid has improved permeability, and leads to significant reduction in wrinkle depth (9).
Improve Wound Healing
Not only is hyaluronic acid great for water retention and hydration, it is necessary for wound healing and tissue repair. When our bodies become physically injured and the wound healing process begins, our bodies naturally increase synthesis of HA. Because of our biological signaling pathways (in specific, Notch and Wnt), studies have shown that HA is crucial to skin tissue repair and wound healing (14). What is interesting is that, depending on its molecular weight, HA can be helpful for different things. Studies have shown that high molecular weight hyaluronic acid helped minimize scar formation, while low molecular weight hyaluronic acid helped with initiating scar formation (15). Either way, it’s been shown that HA helps with initiating wound healing and improving tissue injuries.
Reduce Dry Eyes
On top of being present in skin, joints, tendons, etc., HA is found in the vitreous humor. The vitreous humor is the fluid that is found inside of the eye, behind the lens. The fluid is clear in order for light to be able to pass through and be analyzed through the retina. Many eye drops contain a low percentage of hyaluronic acid, to help with eye health. Studies have shown that HA solutions help reduce dry eye symptoms, improve the efficacy of cornea epithelial cells, and improve the tear film (17). HA has also been used in mixed solutions to help reduce cornea damage from UV-rays (18).