What Happens If You Use Expired Hair Dye?

Most hair dyes don’t have an expiration or ‘best before’ date printed on them. So if you’ve had a bottle of hair color for a while, it can be difficult to know if it’s still good to use.

Expired dye will probably not cause you any harm, but it may not work as expected. In this post, we discuss what happens if you use expired hair dye. I also explain how to tell if a bottle of hair dye is still good to use and how to store hair dye properly.

Does Hair Dye Expire?

Yes, it does.

In fact, all beauty products expire. They don’t go bad the same way food products do. They may not always get smelly or change how they look. But the ingredients in these products degrade over time.

Here’s a video showing the difference between shampoo that’s in good condition and one that’s expired.

Expired beauty products, including hair dye, may look the same as when they were new but they may not be safe to use or they may not work as expected.

So, yes, hair dye expires. But the expiration date depends on whether it’s been opened and where it was stored.

How Long Does Unopened Hair Dye Last?

Unopened hair dye generally lasts for three years. After that, you may not get the results you anticipate since the ingredients in the dye have oxidized or degraded.

But even the unopened shelf life depends on how well the dye is stored. For the best longevity, hair color and most other beauty products should be kept in a cool, dry and dark place.

If the dye was stored in a bathroom where it’s humid, moisture may have penetrated inside along with bacteria. The dye is no longer safe to use.

If the dye was stored in a place where it might have frozen or gotten too hot (e.g. in an uninsulated garage), the extreme temperatures have likely permanently degraded the ingredients.

How Long Does Opened Hair Dye Last?

Once you open a bottle of hair dye, the countdown to expiry speeds up. Instead of three years, now you have six weeks to use the dye before it expires.

Check your particular hair dye for specific recommendations. Even though most hair dyes don’t have an expiry date, some will tell you how long the product will last after you’ve opened it.

Once opened, hair dye lasts for a shorter period because it’s been exposed to air. Ingredients like copper in the dye will start to oxidize, and this can result in a different hair color if you use the dye after the 6 week period.

Opening hair dye also exposes it to bacteria and microbes in the air. Over time this can affect the safety of the product.

There is a big exception to the 6-week expiry date. Mixed hair dye must be used immediately. 

Hair dye kits typically come with two bottles: the hair color itself and a bottle of developer, which contains hydrogen peroxide.

You have to mix the two before applying the dye to your hair. Once you’ve mixed the dye and developer, you must use it within one hour. Some manufacturers give an even shorter period of 30 minutes.

Check the label for specific instructions.

If you have some mixed dye left over after coloring your hair, toss it. Do not attempt to store it or, even worse, use it again.

If you don’t need a lot of dye, just combine a bit of the dye and developer. Then tightly seal the remaining dye and developer and store them in a cool, dark and dry place. You can still use them within six weeks.

What Happens If You Use Expired Hair Dye?

There’s currently no evidence that using expired hair dye will damage your skin or cause your hair to fall off.

But using expired hair dye can still have some unwanted results.

  • Because of degradation, the hair dye may not work at all. The problem could be with the hair color, the developer (hydrogen peroxide decomposes quickly once exposed to air), or both.
  • Even if the hair dye works, it may not work as expected. Oxidation of ingredients may make your hair darker than you expected. It may also cause discoloration or uneven color.
  • Even if the expired hair dye produces the results you wanted, your hair color might fade faster than you anticipated. This is especially common with expired semi-permanent and demi-permanent hair dye.
  • If you are applying hair dye to cover up gray hair, it may not provide full coverage.
  • In some cases, expired hair dye can cause an allergic reaction especially if you have a sensitive scalp.

What Happens If You Use Expired Mixed Hair Dye?

What Happens If You Use Expired Mixed Hair Dye?

Expired unmixed hair dye is usually harmless on your skin and hair. Expired mixed hair dye is another case altogether.

Remember we said mixed hair dye has a very short shelf life – around 30 minutes to 1 hour. That’s because once you mix the developer and hair color, they start reacting and forming other compounds.

Once this reaction comes to an end – which is usually within half an hour to an hour – you have a completely different product on your hands.

Mixed dye that’s been stored for several hours or days is dangerous to use. You’ll notice that it has become a liquid, instead of the creamy easy-to-apply texture it was before.

If you apply this liquid to your hair, it will damage your hair and scalp. It could lead to weak and frizzy hair that falls out easily.

Expired mixed hair dye can also cause itching and burning on your scalp.

If you have any leftover mixed dye, throw it out. It’s dangerous to reuse and probably won’t work anyway.

How To Tell If Hair Dye Is Expired

If you know when an unopened bottle of hair dye was manufactured, count three years from that date. If it is older than three years, then it’s expired.

If the bottle is opened, count six weeks since you opened it. If it’s older than that, it’s probably not in a good condition.

If you are not sure about the dates or if the dye was not stored properly, here are other signs that it is expired.

  • The cap is open or loose. Dye must be tightly sealed to remain in good condition. If it’s been constantly exposed to air, it’s safer to toss it out. Oxidation and bacterial contamination have likely affected the safety and condition of the dye.
  • There is caking around the cap. This is an indication that moisture has penetrated into the dye. This usually happens if the dye is stored in a humid place such as the bathroom or if it’s exposed to the elements.
  • The dye smells funky. This is an indication of contamination, oxidation or other reactions.
  • Check the color and condition of the dye. Is it the same color as the one shown on the box? Does the consistency and texture look unusual? Have the ingredients separated? If you suspect the dye is not in good condition, be safe and throw it out.
  • Check the storage conditions of the dye. If it was stored in a hot, cold, moist or sunny place, don’t use it.
  • The condition of the package can also tell you a lot about the condition of the dye. If the packaging is damaged, wet, faded or has some other kind of damage, the dye inside is probably not good as well. Sometimes, you may also notice the bottle is swollen, indicating unwanted reactions inside.
  • Check if there’s an expiration date on the box or bottle.
  • If you have no idea how old the dye is, throw it out to be safe. The last thing you want is a hair disaster that’s expensive to correct.

How to Properly Store Hair Dye

If you’ve bought hair dye and don’t plan to use it immediately, don’t open it. It will last longer – up to three years – if you keep it sealed.

Keep it in a cool dry place away from direct sunlight. A bedroom cabinet is perfect. Avoid keeping it in the bathroom, even if it’s in a closed cabinet, the garage, or any other place where it will be exposed to extreme temperatures or humidity.

If you’ve opened the dye, seal it again as soon as you pour out the amount you need. For extra protection, put it in an airtight container or bag and then keep it in a cool, dry and dark place.

If you have leftover mixed dye, do not store it. Throw it out and mix a fresh batch when you dye your hair again.

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