MTOR and hydrops fetalis: To delineate the molecular pathway linking arginine deficiency‐induced ROS accumulation to hair follicle (HF) growth suppression, we interrogated mTOR signaling—a conserved nutrient‐sensing hub engaging in bidirectional redox crosstalk.[45, 46, 47, 48, 49] Assessment of ORS cells models under arginine deprivation demonstrated dose‐dependent mTOR pathway inhibition via Western blot analysis (Figure S5A, Supporting Information).