Hyaluronic acid is a type of polysaccharide called a glycosaminoglycan. Also known as hyaluronan or hyaluronate, it occurs naturally in the human body and is central to regulating cell growth and renewal. In fact, it is found extensively in connective, epithelial, and neural cells. As such, hyaluronic acid has found its way into many skin care products, particularly anti-wrinkle formulations. In addition, it has been credited with extending life in those who consume high amounts in the diet, resulting in the media dubbing it as the "key to the fountain of youth."
The fact that this acid binds with water accounts for the special interest in it in dermatology. When injected under the skin, it provides an appearance of fullness at the site, smoothing out fine lines and wrinkles for up to six months. Administration of this cosmetic procedure is available in the form of Restylane®, a non-animal stabilized source of hyaluronic acid (NASHA) that is produced from bacteria. In addition to being a corrective procedure for moderate to heavy wrinkling of facial skin, it is a popular lip augmentation treatment.
As a skin care procedure, the injections present certain side effects for some individuals. Temporary bruising, swelling, and redness at the injection site are fairly common. Subjects undergoing therapy with nonsteroidal anti-inflammatory drugs, or who supplement with vitamin E or St. John’s Wort, are advised to stop taking these medications at least one week prior to receiving these acid injections because of an increased risk of bleeding.
Ironically, while this acid may be touted as a beauty enhancer, it can also diminish the appearance of skin and even cause tissue damage. This is because hyaluronic acid readily degrades in the presence of at least seven enzymes classified as hyaluronidases. Degradation is significantly accelerated when the skin is exposed to high levels of ultraviolet rays (UVs) from the sun. As a result, both the acid and its by-products are sometimes responsible for promoting inflammatory response and even tumor cell proliferation. In fact, hyaluronan levels are sometimes used as a biomarker for prostate and breast cancers.
Since this acid plays a key role in tissue repair, however, it has solid application in several medical treatments. For instance, it has been used extensively to speed healing after ophthalmic procedures, such as corneal transplantation, and surgery to correct retinal detachment and glaucoma. It's also used as a form of injection therapy for osteoarthritis of the knee, ankle, and shoulder.