Hair loss caused by kidney yin deficiency can be regenerated. Kidney yin deficiency mainly refers to the insufficient manifestation of kidney fluids, and so it can be treated by nourishing the kidney yin. To nourish kidney yin in daily life, one should eat more foods that enrich kidney yin, or take some medicines that bolster kidney yin for conditioning. You can choose an over-the-counter medicine like Liuwei Dihuang Pills, but it needs to be taken consistently for a period before effectively improving the symptoms of hair loss. In daily life, you can also eat more softshell turtle, blackfish, etc., which also helps to improve the state of kidney yin deficiency. (Specific medications should be taken under the guidance of a physician.)