Have you ever had facial or body filler surgery? 

Do you know what the degree of cross-linking is? The degree of cross-linking is the degree to which an umbrella-like skeletal structure is formed between the chains of hyaluronic acid molecules using a cross-linking agent. The degree of cross-linking is related to the amount of cross-linking agent put into the hyaluronic acid. The greater the amount of cross-linking agent administered, the more umbrella-like skeletal structures in the hyaluronic acid and the higher the corresponding degree of hyaluronic acid cross-linking. The degree of cross-linking affects the viscoelasticity and maintenance time of sodium hyaluronate gels. As the amount of cross-linking agent administered increases, the rate of increase in the elastic modulus of hyaluronic acid gradually becomes greater than the increase in the viscous modulus. The gel will tend to be more solid and better suited to shaping. 

The higher the degree of cross-linking: the longer the duration of the hyaluronic acid at the same concentration. The higher the cross-linkage, the harder the texture and the longer it lasts. Suitable for use on the arch of the eyebrow, the base of the hill and the chin.

The medium degree of cross-linking: slightly soft texture, suitable for soft tissue filling and wrinkle reduction. For example, forehead, temples, apples, nasolabial folds. 

The low degree of cross-linking: It is more suitable for filling fine areas, such as wrinkles on the forehead and other fine lines.