Hyaluronic acid, a naturally occurring compound found in the skin, joints, and connective tissues, serves as a vital component for maintaining hydration and suppleness. Its gel-like texture aids in moisturizing the skin, rejuvenating cells, and diminishing the appearance of wrinkles and fine lines.
Beyond its cosmetic applications, hyaluronic acid offers numerous additional benefits. It alleviates joint discomfort and enhances wound healing, while also being utilized in eye drops for treating dry eyes.
In the realm of cosmetics, hyaluronic acid stands out for its exceptional ability to retain moisture, making it a sought-after ingredient. Many are intrigued by its diverse applications and potential advantages. Hyaluronic acid creams provide hydration and moisture retention for the skin, and it can be taken orally as a supplement or applied topically as a cream.
Moreover, hyaluronic acid serves as a popular injectable dermal filler, capitalizing on its unique properties. As collagen, hyaluronic acid, and skin elasticity naturally diminish with age, wrinkles and sagging become more prominent. Cross-Linked dermal fillers, utilizing hyaluronic acid, offer a solution by smoothing wrinkles and restoring volume to the skin.
The molecular structure of hyaluronic acid enables it to retain significant amounts of water, contributing to skin hydration and firmness. In this article, we'll explore the two forms of hyaluronic acid and their benefits.
Hyaluronic acid exists in two primary forms based on its composition: non-cross-linked hyaluronic acid and cross-linked hyaluronic acid. The naturally occurring hyaluronic acid found in the body's connective tissues is typically linear or non-cross-linked. Detailed studies have examined the physical properties, permeability, and degradation rates of both cross-linked and non-cross-linked hyaluronic acid. To grasp the differences between the two, it's essential to understand their physical attributes and clinical performance.
Cross-linked hyaluronic acid-based gels have gained widespread use in the cosmetic industry as injectable dermal fillers. Cross-links refer to intermolecular bonds that enhance the stability and longevity of clinical implants.
In its natural state, hyaluronic acid is non-cross-linked and degrades more rapidly. To enhance its stability and durability, it undergoes chemical modification to create cross-linked HA, resulting in a thicker gel. Cross-linked hyaluronic acid is significantly more stable and long-lasting compared to its natural form. The process of cross-linking makes the product thicker and more difficult for the body’s enzymes to break down and disintegrate.
This structure makes hyaluronic acid capable of retaining large amounts of water and providing hydration to the human body’s connective tissues for longer periods of time. The process of cross-linking makes the hyaluronic acid resistant to enzymatic breakdown and thereby it is able to remain in the body for months after filling.
Cross-linked hyaluronic acid offers superior longevity and stability when compared to non-cross-linked or natural hyaluronic acid, making it the preferred choice for dermal fillers. Its effects can last up to 12 months when used for filling. Due to its reduced susceptibility to enzymatic degradation, cross-linked hyaluronic acid remains on the skin surface for a longer duration, prolonging its anti-wrinkle effects.
Several studies have shown that cross-linking hyaluronic acid to form smaller particles improves its diffusion and penetration through both human epidermis and animal skin compared to linear or non-cross-linked hyaluronic acid.
From a physics perspective, elasticity refers to an object's ability to return to its original shape after being distorted. The elastic and viscous characteristics of hyaluronic acid primarily hinge on its concentration and cross-linking. Cross-linked hyaluronic acid exhibits greater elasticity and viscosity compared to its non-cross-linked or linear counterparts.
The skin penetration properties of a molecule are inversely affected by its size and molecular weight. Consequently, a molecule with higher molecular weight penetrates less deeply than one with lower molecular weight. Cross-linked hyaluronic acid, with its larger size and higher molecular weight, penetrates less deeply. As a result, cross-linked products remain at the site of filling for longer periods, rather than diffusing into deeper layers of the skin.
