头发白了，还能变黑吗？医生的答案出乎意料！

Core Viewpoint - The article discusses the causes of premature graying of hair and emphasizes the importance of scalp care in maintaining healthy hair, introducing a specific hair care product that claims to address these issues effectively [7][11][21]. Causes of Graying Hair - Graying hair is primarily caused by the loss of melanocytes in hair follicles, which can be due to pathological reasons such as follicle atrophy and chronic scalp inflammation [8][11]. - Physiological reasons include genetic factors and aging, with studies indicating no significant correlation between premature graying and factors like obesity, alcohol consumption, or stress [11][15]. Importance of Scalp Care - The health of hair follicles and hair is fundamentally linked to the condition of the scalp, which serves as the environment for hair growth [19][21]. - Many commercial shampoos only clean hair without effectively caring for the scalp, highlighting the need for products that focus on scalp health [24][25]. Product Introduction - The article introduces the "Rebuild Ginger Amino Acid Nourishing Shampoo" developed by a team from Peking University, which claims to provide deep scalp cleaning and nourishment [29][31]. - This shampoo utilizes a patented scalp care technology and contains a high concentration of natural ingredients like ginger juice (30%) and various herbal extracts [31][112]. Product Efficacy - Third-party testing shows that the shampoo has significant efficacy in controlling oil (87.88%), reducing dandruff (81.82%), and alleviating itching (81.82%) [32]. - The product is also reported to improve scalp moisture retention by 16.79% after four weeks of use, indicating its effectiveness in restoring scalp health [99]. Consumer Feedback and Promotions - Positive consumer feedback highlights improvements in scalp cleanliness and hair texture, with many users reporting reduced oiliness and dandruff [44][88]. - The product is offered at a promotional price of 98 yuan per bottle, with additional trial offers to encourage consumer testing [50][161].