In Traditional Chinese Medicine (TCM), Yin and Yang are two complementary forces that govern every organ and function in the body. When they are balanced, the body stays healthy and stable. However, when Yin weakens, the body loses its cooling and nourishing capacity. Known as Yin deficiency, this condition triggers Yang energy to dominate, causing internal heat, dryness, and restlessness. This article explores what happens when Yin is deficient and why it often affects those living in Singapore.