On whether glycolic acid will expire
All things in the world have their own characteristics, and glycolic acid is no exception. To understand whether glycolic acid will expire, it is necessary to investigate its essence and environment.

Glycolic acid has active chemical properties. Its molecular structure contains carboxyl and hydroxyl groups, which make glycolic acid can participate in many chemical reactions under suitable conditions.

In terms of its own chemical stability, carboxyl groups are easy to neutralize with alkali substances, and hydroxyl groups can participate in reactions such as esterification. If the storage environment is improper, the chemical structure of glycolic acid is easily damaged in case of alkaline substances or high temperature, strong light, etc., which may be regarded as one of its "expiration" manifestations.

Furthermore, from a microbial perspective, if the environment in which glycolic acid is located is suitable for the growth of microorganisms, microorganisms may use glycolic acid as a nutrient source for growth and reproduction, thereby changing the chemical composition of glycolic acid and causing it to lose its original characteristics, which can also be called "expired".

Storage conditions have a significant impact on the shelf life of glycolic acid. If it is well sealed and placed in a cool, dry and dark place, its chemical change rate will slow down and its shelf life will be extended. Conversely, if it is exposed to air, fully exposed to moisture, oxygen, etc., or in a high temperature environment, its deterioration rate will accelerate.

In summary, glycolic acid will indeed expire. Whether it expires or not is not only related to its own chemical properties, but also closely related to the preservation environment. In order to maintain the quality and effectiveness of glycolic acid, it needs to be properly stored and a suitable environment should be created according to its characteristics.