What to Know about Expired Shampoo

Medically Reviewed by Debra Jaliman, MD on July 23, 2023
4 min read

Half-empty shampoo bottles are a common site in plenty of bathrooms. You aren’t alone in wondering if that shampoo you’ve had for over a year is still usable. Does shampoo go bad under normal circumstances? You must check out the expiration date and any other fine print before lathering up. Knowing when and how your shampoo expires helps you avoid unnecessary health risks. 

Shampoo ingredients and formulas differ depending on the manufacturers and shampoo types. They generally contain sodium laurate sulfate, sodium lauryl sulfate, panthenol, citric acid, cocamidopropyl betaine, and zinc pyrithione. Medicinal shampoos contain specific chemicals that help in treating conditions like lice and scabies.

Each ingredient has a role to play and is safe for use. The roles range from keeping your hair clean and bacteria-free to keeping your scalp moisturized and dandruff-free. Some unique brands offer specific benefits like managing your coarse hair and accelerating your hair growth. 

Just like any other consumable, shampoos have a shelf life — which decides how long it will take until a consumable becomes unfit for use. Though you may not find a specific expiration date for your shampoo, you are likely to find a symbol that denotes the number of months the shampoo will be in its best usable state. In most cases, your opened cosmetics will have a shorter shelf life than will those unopened.

This is because opening a shampoo bottle exposes the shampoo’s contents to bacteria and oxygen that slowly causes its decay. Therefore, if you rarely use your hair care products, you can stretch their use to a little over a year. But, you must take note of the month you purchased or opened your new bottle.

When your shampoo goes bad, its shampoo contents may start looking lumpy like curdled milk. This typically happens because of improper storage, which causes denaturation —or destruction — of the shampoo components. If you are still uncertain, then check if the shampoo slides smoothly onto your palms or spurts out in lumps.

Also, expired shampoo doesn’t perform as it usually does. If your hair still feels dry or crackly even after having followed your usual routine, then your shampoo is past its prime. You expose your shampoo to bacteria every time you open the product. If you have been on the same hair care regimen for a long duration, chances are that you're using an expired shampoo.  

Skin irritation may happen if you use an expired shampoo. This sign may be tricky to detect, especially if you have been using a trusted brand. But, if your symptoms persist with continued use, this should be a hint enough to reexamine your trusted brand. You may also need to seek out a dermatologist for the prompt resolution of your symptoms. 

Any product that is past the sell-by date has gone through an irreversible chemical change. So, expired shampoo may not deliver on expected results. The use of expired shampoo can cause your hair to look dirty and dull. Expired shampoo may also cause irritation or itchiness to your scalp and eyes owing to the chemical change and allergens.

You may get a scalp infection in the worst-case scenario, depending on the bacteria’s virulence factors. This infection may lead you to have patchy hair loss or get some gruesome wounds. 

If you want to increase your shampoo’s shelf life to the maximum, then opt for one that is in a tube or sprayer. This option limits the chance for water droplets or air to get in and degrade your shampoo. In addition, avoid adding chemicals or water unless deemed appropriate by the manufacturer. Also, strive to store your shampoo in a cool, dark, and dry place when not in use.

Light contains ultraviolet rays that may degrade the various degradable components in your shampoo. This exposure lowers the shampoo's shelf life to less than one year. Some shampoos may contain preservatives and additives that allow them to maintain their quality for months to years. You can choose sulfur-free shampoos to avoid their numerous side effects.

But, the shampoo types have a shorter shelf life, which is a subtle but significant difference when picking the right shampoo

The best way to deal with expired shampoos is disposing of them. First, empty the bottle remnants into a toilet or sink, and then, proceed to dispose of the bottle.

Also, if the shampoo is past expiry but doesn’t appear spoiled, then use the remnants to clean your toilet or clothes.