Do shampoos and conditioners expire? We asked the experts if old products can damage your hair

does shampoo expire
Does shampoo expire? How to tell if it's gone offgetty - Hearst Owned

While I go through mascaras as quickly as I go through salt packets and cleansers as speedily as I do toothpaste, shampoos and conditioners on the other hand are another story. If, like me, you only wash your hair once or twice a week, it means those products will be sitting on your shower shelf for a while.

If you can't remember the last time a shampoo ended up in your recycling bin, it might be time to start thinking about whether your shower essentials are actually going off before you reach the bottom of your tub of conditioner, and what this means for your tresses and scalp.

Fear not, because we asked the experts how you can easily spot if your shampoo and conditioner have expired and how exactly this affects your hair (spoiler: you could be stunting your locks potential).

Here's why you might need to add 'decluttering hair products' to your to-do list...

does shampoo expire
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How can I tell if my shampoo or conditioner has expired?

Yep, just like that Greek yoghurt at the back of your fridge, your shampoo and conditioner can turn bad. However, unlike expired dairy, it's not as simple as taking a whiff to determine if it's suitable to use. We're handing over to Cosmetic Chemist, Carly Musleh to explain:

"Like all cosmetics and personal care, shampoos have a shelf life but there are things to look out for as information will differ from product to product. According to the UK Cosmetic Regulation, if a product has a shelf life lower than 30 months from the manufacturing date it must display a Best Before Date."

This can usually be found on the back of your shampoo bottle at the bottom. It's typically shown in a simple date stamp format or as that little symbol that looks like an open tub that will read '12M' ('M' standing for months), telling you how long the product will be good for once it's been opened.

does shampoo expire
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Obviously, there are exceptions to the rules, which is when you need to start playing detective.

"A formulation should remain stable for the duration of the use by date but if you notice changes in the texture, colour, odour and traces of mould then no longer use it. In shampoos a big tell-tale sign is the change in its viscosity, if it becomes very runny or there’s clear separation then there’s an issue," says Musleh.

If you're wondering about the science behind all of this, Musleh explains that: "Preservation is essential to inhibit spoilage organisms and to prevent the growth of potential pathogens. Since shampoos are water-based products containing surfactants, these are prone to contamination by Gram-negative bacteria, which can reduce the lathering making the product less effective."

It might sound very science-y, but the key takeaway is that the longer your products are open, the more chance there is of bad bacteria and mould making a home inside your fancy shampoo bottle. Class, dismissed.

Is it ok to use expired shampoo?

We know there are some foods you can get away with eating a few days after their sell-by date, but does it work with your shampoo and conditioner?

The signs we've already mentioned to look out for sum up that expired products aren't going to do as thorough a job at cleaning and conditioning as they did in their prime, but it can often lead to worse issues.

"Using any expired product has the potential to cause irritation and sensitivity. Those who have scalp dermatitis are prone to inflammation so an expired product could cause flare-ups and lead to unwanted side-effects. Additionally, once a product expires it is prone to an increase in bacteria which you don’t want near your eyes or damaged skin," Musleh explains.

Essentially, if in doubt, you're better off investing in a new hair wash duo than you are risking it with your old one – itchy scalps are not the one.

does shampoo expire
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What causes shampoos and conditioners to go off?

It's not just old age that causes formulas to go off, there are a few other factors that could be making your haircare products expire sooner than expected.

"Haircare bottles are often left on the window ledge or even on the shower tray, exposing them to hot temperatures and wet conditions regularly, which can lead to contamination and affect the stability," says Musleh.

"Preservatives are pH sensitive, so leaving caps off and allowing water into the bottle will change the pH and affect the product's preservation, which can reduce shelf-life and encourage microbial growth," she adds.

These are all man-made problems, but there are some instances that aren't down to how we care for our beauty products.

"Formulations which don’t have an adequate preservative system will expire faster regardless – however, many natural and organic shampoos contain a higher percentage of oils and extracts which can reduce the lifespan of the product," says Musleh. This is why you might see more 'natural' formulations with shorter expiry dates.

Preservatives also play a key role. "The concern with products labelled ‘preservative-free’ is they may not have the capability to prevent contamination with micro-organisms for the predicted shelf-life of the product, which can put consumers at risk," Musleh explains.

Does anyone else fancy treating themselves to a new shampoo and conditioner? We thought so...

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