Fake urine, also known as synthetic urine, is a substance that is designed to mimic real human urine. It is often used for a variety of purposes, such as passing drug tests or calibrating urine testing equipment. While the shelf life of fake urine can vary depending on the brand and specific product, there are some general guidelines to keep in mind.

Typically, unopened fake urine can last for several years if it is stored properly in a cool, dry place. However, once the product has been opened, its shelf life can be significantly shorter. This is because exposure to air and moisture can cause the fake urine to degrade over time.

Most fake urine products come with instructions that outline how to use and store the product properly. Generally, it is recommended that you use the product as soon as possible after opening it to ensure that it is still fresh and effective.

If you have leftover fake urine after using it for a drug test or other purpose, it is generally not recommended to reuse the product. Instead, you should dispose of it properly and purchase a new product if you need to use it again in the future.

In general, the shelf life of opened fake urine can vary depending on a number of factors, such as the specific brand, storage conditions, and how much of the product has been used. It is always best to follow the manufacturer's instructions for proper storage and use to ensure that the product remains effective and safe to use.