Kye Yong Song

1 Introduction Skin, serving as the primary barrier between the organism and the environment, protects against pathogen invasion and withstands chemical and physical assaults. Throughout an individual's lifespan, skin undergoes numerous changes and transitions, resulting in significant differences between young and aged skin [1].

To the Editor, Over time, the breakdown of collagen and elastin in the dermis leads to a decrease in elasticity and volume. Clinically, this can contribute to wrinkles, rough texture, and laxity. The demand for noninvasive skin tightening continues to grow [1, 2]. In our study, histological analysis confirmed an increase in collagen and elastic fiber especially in the mid dermis after high-intensity, parallel ultrasound (HIPS) tightening (Sofwave, SofWave Medical Ltd., Israel).