Facial Injectable Fillers in Aesthetic Medicine: Clinical Applications and Safety Strategies.

Due to the increasing demand for facial rejuvenation and aesthetic enhancement, the use of facial injectable fillers has rapidly expanded and become one of the most widely used cosmetic procedures. These fillers are primarily used for facial rejuvenation, soft tissue augmentation, wrinkle removal, and correcting volume loss or facial disproportion caused by aging, trauma, or infection. Commonly used materials include hyaluronic acid, polycaprolactone, calcium hydroxylapatite, and poly-L-lactic acid, each offering unique benefits in terms of safety, durability, and biocompatibility. Additionally, the longevity and mechanism of action vary significantly among fillers. Hyaluronic acid provides immediate volume but requires crosslinking for durability, while polycaprolactone and poly-L-lactic acid stimulate collagen production for longer-lasting effects. Minimally invasive procedures with injectable fillers provide advantages such as enhanced privacy, reduced recovery time, and lower risk, compared with traditional surgery. However, potential adverse reactions - ranging from mild swelling and pain to severe complications, such as vascular occlusion, nodules, and even blindness - remain a critical concern. A thorough understanding of facial anatomy, particularly of vascular danger zones, is essential to mitigate risks, such as tissue necrosis and vision loss. In this review, we comprehensively analyze the properties, clinical applications, and mechanisms of action of major filler materials, while emphasizing reported complications and their management strategies. By integrating current evidence, we aim to guide clinicians in selecting appropriate fillers, optimizing injection techniques, and minimizing risks, thereby improving patient outcomes in aesthetic medicine.