When you have an old shampoo on hand, it’s important to pay attention to its expiration date. Shampoo that has passed its expiration date may have deteriorated or undergone changes in its ingredients, so it’s not recommended to use it without consideration. In this article, we will explain the expiration dates of shampoos, detailing how they differ depending on the type of shampoo and whether the bottle is opened or unopened. We will also introduce proper storage methods and important points to consider when refilling shampoo, so be sure to take a look.
For unopened shampoo, the expiration date is generally around 3 years from the date of manufacture. Shampoos are classified as either cosmetics or quasi-drugs, and their quality control and labeling are strictly regulated under the Pharmaceutical and Medical Devices Act (formerly known as the Pharmaceutical Affairs Act). According to this law, products that maintain stable quality for more than 3 years after manufacturing are not required to display an expiration date. Therefore, even if there is no expiration date on the packaging, it is assumed that the product will remain stable for at least 3 years. However, factors such as storage conditions can affect the product, so it cannot be guaranteed that the shampoo won’t deteriorate within 3 years. If an expiration date is provided, be sure to adhere to it.
Once opened, shampoo is generally good for 6 months to 1 year. The expiration date listed on the bottle applies only to unopened products. Once the shampoo is exposed to air, its ingredients gradually begin to degrade. It is recommended to use the shampoo as quickly as possible after opening, regardless of the expiration date. Shampoos left in high-humidity environments, like bathrooms, are especially prone to faster degradation.
For organic shampoos, even unopened products often have a shorter shelf life, typically around 1.5 to 2 years. This is because they often contain natural ingredients and lack preservatives, which makes them more prone to deterioration compared to regular shampoos.
Shampoo samples and amenities have the same expiration guidelines as regular shampoos—about 3 years if unopened. After opening, they can last for 6 months to 1 year, provided the packaging remains intact. However, if the product has been exposed to air or contaminated by water, it’s safer not to use it.
The expiration guidelines for conditioners and treatments are similar to those for shampoos. Unopened, they typically last up to 3 years. After opening, it is recommended to use them within 6 months to 1 year.
For organic products, the expiration date tends to be shorter, just like with shampoos, due to the use of natural ingredients and the lack of preservatives.
If your shampoo has developed a strange odor, it is a sign that bacteria may have started to grow. In such cases, do not use the shampoo. Using it could cause rashes, itching, or even lead to more serious skin conditions.
Shampoo is usually in a stable, emulsified state, with all ingredients evenly mixed. However, if the shampoo is past its expiration date, the ingredients may start to separate, causing water or oil to rise to the surface or the color to turn marbled. Using deteriorated shampoo with separated ingredients can cause scalp problems, so it should be avoided.
Proper storage is essential to maintain the quality of your shampoo. It helps prevent degradation, bacterial growth, and changes in consistency or effectiveness. Proper storage methods for both opened and unopened shampoos are important to ensure their longevity.
When storing unopened shampoo, it’s important to avoid high temperatures and humidity. Don’t store it in the bathroom; instead, keep it in a well-ventilated area. Some shampoos may have shorter expiration dates, so be sure to check the bottle beforehand and use it before it expires.
Opened shampoo is also sensitive to high temperatures and humidity. Leaving it in the bathroom can accelerate its deterioration and promote bacterial growth.
If you plan to use the shampoo quickly, leaving it in the bathroom is generally fine. However, if it will take a while to finish the bottle, consider removing it from the bathroom after each use.
Be mindful to prevent water from entering the bottle, as this can cause the shampoo to deteriorate more quickly.
When refilling your shampoo bottle, it’s important to clean the bottle thoroughly and let it dry completely before adding the new shampoo. If you simply top off the bottle when it’s running low, you risk starting with a mix that may already contain water or bacteria, which can accelerate deterioration. Don’t skip this step—take the time to wash the bottle properly each time you refill it to maintain the quality of the shampoo.
This article has covered the expiration dates of shampoos, including proper storage methods and important points for refilling. Although shampoo may seem less likely to spoil, it contains moisture, which causes it to degrade and change over time. Using shampoo past its expiration date can potentially lead to unexpected scalp issues. Since shampoo directly affects your scalp, it’s important to adhere to expiration dates to ensure safety and effectiveness.
Source : https://answerweb.artnature.co.jp/archives/2111