Hyaluronic Acid (HA) is a natural polysaccharide molecule in the human body. It belongs to the Glycosaminoglycan (GAGs) family. It is found mainly in connective, epithelial, and nerve tissue, especially in the skin, vitreous, and joint fluid of the eyes. Hyaluronic acid plays a vital role in maintaining tissue structure and function.

Function:
1. Moisturizing function. Hyaluronic acid is a very effective moisturizing agent. It has a strong water absorption capacity and can absorb and maintain the weight of hundreds of times the amount of water, thus helping the skin to maintain moisture and elasticity. This makes hyaluronic acid an essential ingredient in many skin care products, especially moisturizers, extracts, and masks.

2. Lubrication and cushioning in joints. Hyaluronic acid is one of the main components of joint fluid. It lubricates and cushions joints reduces friction between them, protects articular cartilage, and relieves pain and discomfort during exercise. This makes hyaluronic acid commonly used to treat joint diseases such as osteoarthritis.

3. Promoting wound healing. Hyaluronic acid plays a vital role in promoting wound healing. It can promote cell proliferation and migration, regulate inflammatory response, and accelerate tissue repair and wound healing. Therefore, hyaluronic acid is commonly used in wound care products such as wound dressings and healing gels.

4. Anti-aging with age. The body's hyaluronic acid gradually decreases, leading to dry, loose skin and wrinkles. External use or injection of hyaluronic acid can increase skin moisture and elasticity, reduce wrinkles and fine lines, and delay skin aging. Therefore, hyaluronic acid is widely used in anti-aging skin care products and cosmetic injections.

5. Ophthalmic hyaluronic acid is a viscoelastic agent in ophthalmic surgery to help maintain eye structural stability and promote postoperative recovery. In cataract surgery, for example, hyaluronic acid helps maintain the depth of the anterior chamber and protects corneal endothelial cells.

6. Drug delivery as a Biocompatibility carrier, hyaluronic acid can be used in drug delivery systems. It can increase the stability and targeting of drugs, improve the efficacy of drugs, and reduce side effects. For example, local drug delivery systems often use hyaluronic acid to enhance absorption and bioavailability.

7. As a soft tissue filler, hyaluronic acid injection is used for facial contour reconstruction, wrinkle filling, and lip thickening. It provides an immediate filling effect, while its biodegradability makes the impact natural and not permanent in the body.

8. Hyaluronic acid is widely used in skin care, cosmetic injection, treatment of joint diseases, ophthalmic surgery, and drug delivery because of its excellent moisturizing, lubricating, repairing, and anti-aging properties. It is vital in keeping skin healthy, promoting wound healing, and improving joint function.

Side effects:
* anaphylaxis: Although rare, some people may develop anaphylaxis from ingredients in hyaluronic acid products, such as preservatives or other additives. Symptoms include redness, itching, and a rash.

* infection: in cosmetic injections, infection may occur if the aseptic procedure is not performed correctly. Signs of infection include redness, heat, and pain.

Injection-related side effects:
* Swelling and bruising: this is a common short-term side effect after injection and usually resolves spontaneously within a few days.
* Pain and discomfort: mild pain and discomfort may occur at the injection site.
* Nodules and lumps: sometimes, small nodules or lumps may form after hyaluronic acid injection and may require further treatment or injection of lysozyme.

Joint injection side effects:
* joint pain: after injecting hyaluronic acid into the joint, some patients may experience temporary pain or discomfort.
* local reactions include swelling, fever, and joint stiffness, which usually subside within a few days.

Eye surgery-related side effects:
* inflammation: using hyaluronic acid in eye surgery may trigger an inflammatory reaction that requires medical intervention.

Measures to reduce side effects:
* choose appropriate products: use certified and quality-assured hyaluronic acid products, and avoid using products containing potentially allergenic ingredients.
* Allergy Testing: before using the new hyaluronic acid product, a local allergy test can be performed to confirm no allergic reaction to the skin.
* Professional Operation: trained professionals should perform cosmetic and medical injections in a sterile environment to ensure safe operation.
* Postoperative Care: follow the advice of the Doctor after the injection, take appropriate care, and rest to reduce the incidence of side effects.

Although hyaluronic acid is generally considered safe and effective, some side effects may occur. The risk of side effects can be greatly reduced by selecting appropriate products, conducting allergy tests, being operated by professionals, and providing postoperative care. If serious discomfort or persistent side effects occur, seek medical attention immediately.

Hyaluronic Acid