Hyaluronic acid stock solution is a kind of hyaluronic acid (HA), also called uronic acid. Natural hyaluronic acid is a kind of macromolecular polysaccharide, which is a linear macromolecular polysaccharide composed of glucuronic acid -N- glucosamine acetate as disaccharide molecular unit. Hyaluronic acid originally exists in the dermal tissue of human skin in the form of colloid, which is responsible for storing water, increasing skin volume and making skin look full, plump and elastic. However, hyaluronic acid will disappear with age, making the skin lose its water storage capacity, gradually becoming dull, aging and forming fine wrinkles. There are five kinds of micro-plastic injection filling materials that are easily confused with hyaluronic acid, namely Ogilvy (or Ingerfrault), silicone oil, paraffin oil, cellulose and collagen. There is a simple way to identify Ogilvy. Some hyaluronic acid containing Ogilvy is mostly sold in beauty salons, and some unqualified plastic surgeons bring their own injections to beauty salons. One of them had an injection in a beauty salon, and his temple was swollen after the injection. This is Ogilvy's performance. Now the streets are full of fake hyaluronic acid and collagen. The criminals won the favor of some beauty seekers with low spending power at low prices and were cheated as a result. So it needs good identification. Identification step: Step 1: Squeeze a drop of colloidal substance from the needle tube and put it on white paper. If there is oil penetration and halo diffusion, then this thing is definitely not hyaluronic acid, but definitely silicone oil or paraffin oil. This kind of material is prohibited by law. Step 2: If it is water diffusion, it may be hyaluronic acid, Ogilvy (or IngelFallot), cellulose or collagen. At this time, further identification is needed! The identification method is: drop a drop of hyaluronic acid in the palm of your left hand, and then touch it repeatedly with your right hand. After a few minutes, after most of the water evaporates, you can see that there are sandy crystal particles in the remaining residue through finger touch or naked eye observation, and there is nothing else. Then this is cross-linked hyaluronic acid, which can basically be confirmed to be real hyaluronic acid and can be used. The third identification method: put the extruded product on the flat glass and observe it the next day. As a result, after a night of water volatilization, the residual molded parts on the glass plate were analyzed. If these residues are all molded components, like the accumulation of smoothies, it must be hyaluronic acid. If it is a hard shell-like opaque scab, it is usually Ogilvy; ? If it is a soft yellowish soft film, it is usually cellulose. If it is not volatile oil, it must be silica gel oil or paraffin oil. If there is nothing left in the end, it is probably non-crosslinked hyaluronic acid! The fourth identification method: for the identification of whether the solid component is hyaluronic acid, the enzymatic hydrolysis experiment method can be used. The procedure is: put the solid particles into a container filled with hyaluronidase in a 45-degree constant temperature water bath box, and the solid particles can be degraded in about 2 hours. If it does not degrade, it is definitely not hyaluronic acid. This is brine tofu, everything has its vanquisher! No one can fool you by the above methods! Distinguish between true and false crosslinked hyaluronic acid, you are an expert!