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Poly-L-lactic acid- What’s New?


「Poly-L-lactic acid” injections have been popular in Hong Kong for several years, with ideal filling effects and safety. In the early stages of use, doctors did not fully understand its characteristics, leading to increased side effects.

Fortunately, after continuous communication and improvement, the technology is now very mature. In September 2014, the academic journal “Journal of Drugs in Dermatology” published a review article sharing the experience of using “Poly-L-lactic acid” for many years, which is worth considering.

Since the introduction of “Poly-L-lactic acid” injection in 1999, it has been widely used in medical aesthetics treatments. “Poly-L-lactic acid” can effectively stimulate collagen, with results lasting up to two years. In the early stages of use, there were frequent minor side effects such as injection site pain, redness, bruising, inflammation, and nodular formation. Most side effects will naturally disappear in a few days, but nodules can persist for several months or even more than a year. Most nodules are of the invisible type, while a small portion are visible. Although 95% of nodules will naturally disappear, some may require injection of physiological saline or steroids for treatment. According to years of research, these nodules can be prevented.

The reason for nodule formation is that the “Poly-L-lactic acid” powder is unevenly distributed in the skin. When the “Poly-L-lactic acid” powder gathers together, it causes a foreign body reaction in the skin, resulting in nodules. To reduce the chance of nodule formation, it is essential to start from the preparation of the powder. It is generally recommended to mix more than 5 milliliters of physiological saline or sterile water 48 hours before injection, and to shake it appropriately during the period. A suitable amount of anesthetic solution should also be mixed before injection. During injection, the doctor’s technique is critical. The injection should be evenly distributed in the appropriate skin layer, and some areas prone to nodule formation, such as the corners of the mouth, eyes, and forehead wrinkles, should be avoided. Doctors should also try to avoid injecting in the superficial skin, as nodules are more likely to form in the superficial skin. Post-injection care is also critical, and patients should massage the area at regular intervals for five days to distribute the powder more evenly.

Although “Poly-L-lactic acid” has ideal results, and the injection method has matured, there are still certain risks. If you want to know whether you are suitable for injection, it is best to discuss it with your doctor.

*European Expert Recommendations on the use of injectable Poly-L-Lactic Acid for facial rejuvenation. Volume 13 Issue 9. Journal of Drugs in Dermatology.