Is There an Expiration Date for Shampoo? Experts Share When to Discard It

All beauty products have an expiration date. This is a tough truth for those who tend to hoard products for future use or delay using them due to their high cost or discontinuation. However, beauty products do have a limited shelf life, and your shampoo and conditioner are no exception. Two cosmetic chemists explain how to determine if your shampoo has expired, whether it's safe to use expired shampoo, and tips to extend the life of your bottle.

How to Identify Expired Shampoo

Shampoos generally consist of water, surfactants (such as sodium lauryl sulfate), conditioning agents, and often preservatives. Common synthetic preservatives include parabens, formaldehyde-releasers, fragrances, and thickeners (natural shampoos usually avoid these additives). Shampoos may also feature essential oils and vitamins like vitamin E. Regardless of the specific ingredients, here’s how to determine if your shampoo has expired.

Check for an Expiration Date

Unopened shampoo typically remains effective for approximately two to three years. Once opened, its lifespan depends on the "period after opening" (PAO) date indicated on the label.

"Most shampoos are designed to last up to 18 months after opening and are marked with a PAO symbol on the packaging," explains cosmetic chemist Vince Spinnato. "If the bottle remains unopened, it will expire three years from the purchase date." Even the best shampoos will gradually lose their quality over time.

Certain products feature a PAO number (period after opening) on the label, such as 12M, 18M, or 24M, where M denotes months. This indicates the shelf life after opening. "In a GMP-compliant (good manufacturing practices) facility, this is rigorously tested to ensure the product's effectiveness over time through accelerated shelf-life testing," says cosmetic chemist David Petrillo. "If no PAO is listed, contact the manufacturer and provide the batch number for reference."

Inspect the Contents of the Bottle

Many of us likely don’t recall when we first opened our shampoo. To determine if yours has expired, watch for visual indicators. "The shampoo’s color, consistency, and scent may change noticeably, making it appear or smell off," explains Spinnato.

"Several issues can arise when a product expires," notes Petrillo. "Often, the chemical ingredients may separate, causing the product to appear lumpy or uneven in texture."

As a general guideline, consider your shampoo expired if it develops a strange odor, appears lumpy, changes color, or fails to lather as effectively as before. This can be harder to detect if the shampoo is in an opaque bottle, making it difficult to see any separation.

Reasons to Avoid Using Expired Shampoo

Using expired shampoo is likely a futile effort. It loses its effectiveness, leaving your hair looking lackluster and unclean. Additionally, the preservatives may no longer function, rendering the product unstable.

The chemical alteration in the shampoo may lead to scalp itching or irritation. Subsequently, mold and bacteria can develop, possibly causing bacterial outbreaks or fungal infections on the scalp.

"[Using expired shampoo] might pose risks since the components were not designed to be used this way or to seep into the skin separately," explains Petrillo. "Although the shampoo isn't left on the hair for long, its ingredients still seep into the scalp's outer skin layers.

In summary: If you're facing problems such as dandruff, scalp itchiness, excessively oily hair, or hair thinning, think about how old your shampoo is before resorting to drastic solutions. Has it expired? If yes, it's best to discard it.

Tips for Extending Shampoo's Shelf Life

Although the expiration date and ingredient efficacy are crucial in deciding whether to retain or discard shampoo and conditioners, the way these products are stored and maintained can also lead to their premature degradation. Consider the following tips:

• Ensure the bottle cap or lid is securely closed after every use to reduce contact with water and moisture.
• Avoid exposing products to direct sunlight, as it can deteriorate active components and accelerate spoilage.
• Store unopened shampoo in a cool, dark area, as heat and light can destabilize its formula, diminishing its potency. 

Commonly Asked Questions

• Does conditioner expire faster than shampoo?

  Both conditioner and shampoo share the same shelf life—two to three years for unopened bottles and up to 18 months for opened ones. The variety of conditioner (deep, leave-in, moisturizing) does not influence its expiration. Since both products contain similar chemicals, preservatives, and ingredients, neither expires quicker than the other.

• Does natural shampoo expire faster than other shampoos?

  Natural shampoos generally have a shorter shelf life compared to conventional ones because they often lack synthetic preservatives. Ingredients such as essential oils, plant extracts, and natural preservatives are more susceptible to rapid degradation.

• Can expired hair products cause hair loss?

  There is no scientific evidence linking expired shampoo and conditioner directly to hair loss. However, expired products can alter your hair's texture and scalp microbiome, potentially leading to thinning or hair loss. If you're worried about these issues, consult a dermatologist or trichologist for advice.