What is the best medicine for kidney yang deficiency?

Kidney Yang Deficiency refers to insufficient Yang energy in the kidneys, mainly manifesting as cold intolerance, cold limbs, soreness and weakness of the lower back and knees, frequent nocturnal urination, reduced sexual function, and other related symptoms. Commonly used traditional Chinese medicine (TCM) formulas or single herbs for treating kidney Yang deficiency include: 1. **Jin Kui Shen Qi Wan (Golden Cabinet Kidney Qi Pills)**: This is a classic formula for replenishing kidney Yang. Its main ingredients include Ramulus Cinnamomi (Gui Zhi), Aconiti Lateralis Radix Praeparata (Fu Zi), Fructus Corni (Shan Zhu Yu), and Rhizoma Dioscoreae (Shan Yao). It warms the kidneys to support Yang energy and promotes qi activity to regulate water metabolism. 2. **You Gui Wan (Right Restore Pills)**: Suitable for kidney Yang deficiency accompanied by deficiency of essence and blood. Its main components include Rehmanniae Radix Praeparata (Shu Di Huang), Corni Fructus (Shan Zhu Yu), Lycii Fructus (Gou Qi Zi), and Cervi Cornus Colla (Lu Jiao Jiao). It focuses on warming and tonifying kidney Yang and nourishing essence and marrow. 3. **Si Ni Tang (Four Reversal Decoction)**: Applicable for severe cases of extreme kidney Yang deficiency with cold extremities. Its main ingredients are Aconiti Lateralis Radix Praeparata (Fu Zi), Zingiberis Rhizoma Crudum (Gan Jiang), and Glycyrrhizae Radix (Gan Cao). It restores Yang energy and reverses cold extremities. 4. **Single herbs** such as Cinnamomi Cortex (Rou Gui), Morindae Radix (Ba Ji Tian), Epimedii Folium (Yin Yang Huo), and Eucommiae Cortex (Du Zhong) also have the effect of warming the kidneys and invigorating Yang energy and may be used under the guidance of a physician. The use of TCM must be based on individual conditions through pattern differentiation and treatment customization. Differences in constitution and symptoms among individuals may lead to different prescriptions.