In Traditional Chinese Medicine (TCM), the organs that most significantly affect skin complexion are the Liver, Spleen, and Kidney. TCM theory posits that a person's complexion is regulated by their internal organs. The "Zang Xiang" theory (Organ Manifestation Theory) in the "Huangdi Neijing" (The Yellow Emperor's Inner Canon) emphasizes the principle of "nourishing from within to beautify the without." If the organs' functions are imbalanced, leading to poor circulation of Qi and blood, deficiency of vital essence, or disharmony of Yin and Yang, the complexion can become dull, prone to dark spots, and the skin may appear puffy and loose. If a person is frequently in a state of being busy, stressed, tense, emotionally down, or irritable, it can lead to "Liver Qi Stagnation." In TCM, the Liver is responsible for the free flow and dredging of Qi, blood, and body fluids throughout the body. When Liver Qi stagnates, it causes chaos and stagnation in the circulation of Qi and blood, resulting in a sallow and dull complexion. This is what is known as "Liver Qi Stagnation."
The reason the Spleen affects the complexion is that, in TCM, the Spleen is considered the source of the production of Qi and blood. It's important to note that the TCM "Spleen" is not the same as the anatomical spleen in Western medicine; rather, it refers to the entire digestive system. The Spleen is said to "govern the middle jiao," meaning its primary role is to absorb nutrients and nourish the other organs. Therefore, the TCM Spleen also governs blood, muscles, and the four limbs, earning its title as the source of Qi and blood production. If diet is improper or mental unrest affects digestive function, it can lead to a condition known as "Spleen deficiency with dampness retention."
As for the Kidney in TCM, it is believed to "govern water," meaning it is responsible for balancing all the body's fluids. Overexertion can lead to a deficiency of Kidney water and an excess of fire, causing deficient fire to rise and become stagnant, which results in rough and dull skin. Furthermore, TCM states that "the Lungs govern the skin and body hair." Because "the Lungs are the master of Qi, and the Kidneys are the root of Qi," a Kidney deficiency or insufficient Kidney water can impair Lung function, causing the complexion to worsen and lose its brightness and clarity.