Since the solvent of hydrafacial injection is hyaluronic acid, no matter which nutrient you choose for hydrafacial injection, it will contain hyaluronic acid in it. In other words, the safety of hyaluronic acid is directly related to the safety of hydrafacial injection, so we will analyze what is hyaluronic acid today: What is hyaluronic acid (hyaluronic acid)? Hyaluronic acid, also known as hyaluronic acid, is a kind of acidic mucopolysaccharide with special water-retaining effect, which is the best moisturizing substance in nature discovered so far, and is known as the ideal natural moisturizing factor. Human skin also contains a large amount of hyaluronic acid, which has an important role in skin moisturizing, can improve skin nutrition metabolism, make the skin soft, smooth, wrinkle, increase elasticity, to prevent aging, while moisturizing or a good transdermal absorption promoter. Compared with the skin of 20-30 years old, the content of hyaluronic acid in the human body is 75% at the age of 30-40 years old, and only 60% at the age of 40 years old and above. During the aging process, the body loses hyaluronic acid and the elasticity of the skin decreases, resulting in fine lines. It gradually decreases as the skin matures and ages. Hyaluronic acid is divided into three categories according to molecular weight: small, medium and large molecules. The larger the molecular weight, the more suitable it is to be injected into the deeper layers. The higher the cross-linking degree, the more viscous the particles are and the less elastic they are. Therefore, filler shaping should choose hyaluronic acid with higher cross-linking degree and larger molecule according to the different parts of the body, whereas hydrafacial injection should use hyaluronic acid with small molecule with low cross-linking degree or no cross-linking, or else the skin will have hard knots. The application of three kinds of hyaluronic acid in medical cosmetology: large molecule hyaluronic acid: large molecule hyaluronic acid is cross-linked hyaluronic acid, with the hardest texture, the longest maintenance time, and the most suitable for contouring. Suitable parts: brow bone, lower bar, mountain root, nose job. Medium molecule hyaluronic acid: slightly soft texture, suitable for soft tissue filling and removing deep wrinkles. Suitable parts: forehead, root of the hill, apple muscle, temples, chin. Small molecule hyaluronic acid: suitable for fine filling and shallow wrinkle removal, non-crosslinked small molecule hyaluronic acid can be used as water light injection. Suitable parts: tear trough, lip groove, silkworm, lip plumping, lip lines, head lines, mouth lines. Now there are many moisturizing products on the market under the banner of “hyaluronic acid”, which also misleads many beauty seekers into thinking that the hyaluronic acid in skin care products is equivalent to the hyaluronic acid used in micropigmentation. In fact, the hyaluronic acid used in skin care products and the hyaluronic acid used in micropigmentation can not be equated, first of all, the hyaluronic acid used in skin care products is non-crosslinked hyaluronic acid, the structure of which is usually liquid, and the form is very unstable. Due to its large molecular weight, it is generally not absorbed by the skin and lasts about 6 hours as a moisturizer. Of course, since hyaluronic acid is the best moisturizing substance found in nature, 2% of hyaluronic acid can firmly lock 98% of the water. So the moisturizing effect is still a little better than ordinary moisturizer. Of course, expectations should not be too high, at best it is just a moisturizer.