In addition, the main substance that affects hair loss is the pH value (that is, the pH value) in the shampoo. The human skin's ability to withstand pH is generally around 5.0. According to the standard requirements of QB/T1974-94, the pH value of shampoo is 4.0- Between 8.0. If the pH exceeds the national standard, it is easy to cause hair loss or too dry hair. For example, if the acid in the shampoo is too much, it will cause the hair to fall off, and in severe cases, it will damage the skin; if the alkali in the shampoo is too high, it will not only cause the hair to dry, but in severe cases it will also cause the skin on the head hurt.