Almost every cosmetic product expires at some point, and hair dye is no exception.
Generally, a permanent hair dye product should be used for no longer than three years after the date it was manufactured, and that goes for the vast majority of hair dye products.
Where it gets a little trickier is when your hair dye doesn’t have a manufacture date and you don’t know how long it had been sitting in the warehouse before you purchased it, or you can’t remember how long it’s been since you acquired it.
It can be hard to tell whether your hair dye is expired or not, unless it’s been a very long time and is clearly not fit for use.
So, what should you be looking out for when trying to determine whether your hair dye has expired? The following will break down everything you might need to know about the inevitable expiration of hair dye products.
How To Tell If Your Hair Dye Has Expired
If you’re in any doubt about whether or not your hair dye has passed its expiration date then you should probably cut your losses and toss it, but there are some signs that should make you seriously consider getting rid.
Your hair dye may be expired (or just generally not fit for purpose) if it’s emitting a strong or sour smell that seems different from the normal ammonia smell you should expect from hair dye, if the liquid is the wrong color or is separated or streaked, if the bottle appears to be cracked or leaking, if there is caking surrounding the bottle’s cap, if the packaging is in any way dented or damaged or, of course, if the colors on the packaging seem to have faded since you first bought the product.
Side Effects Of Using Expired Hair Dye
If you’ve rolled the dice and applied hair dye that you suspected to be expired and it turns out that it is indeed expired, there are a number of side effects you may experience.
Chlorine can turn your hair green if it’s bleached- this is standard, but if you use expired hair dye then your hair might turn green regardless of the color it’s supposed to be turning.
This is because the chemical makeup of the hair dye has been altered over time, so the way it reacts with your hair is different from how the manufacturer intended it.
It doesn’t matter what color’s on the packaging; if your hair dye has expired, it may turn your hair dark green.
Another risk of using hair dye that has expired is your hair not turning dark green, but turning a myriad of other unpleasant colors.
It’s quite the roulette, and in some cases the hair dye might be completely ineffective, meaning your hair will remain the same color.
If your hair dye has expired but fairly recently, you might at first think that it’s worked as intended.
However, even if your hair ends up the right color, it’s possible that it’ll fade far faster than it’s supposed to, so it’s worth neither the time nor the risk.
One of the more serious side effects of using expired hair dye is a burning sensation in your scalp. This can be very irritating and even painful, and it could also result in hair loss in the short term.
Finally, expired hair dye can actually be quite dangerous for your hair, causing serious damage. Your hair could also get a lot frizzier than you’re happy with, which could be a major nuisance to fix.
Different Types Of Hair Dye: Expiration Dates
While the average life expectancy of a hair dye product is three years after its manufacture date, it’s worth noting that there are different kinds of hair dye, and the average expiration date can vary depending on which type.
Permanent Hair Dye
Permanent hair dye should last longer than any other kind of hair dye, due to the chemicals that are present in its makeup. If it hasn’t been opened then permanent hair dye should last you up to three years.
But, remember, just because you haven’t opened your hair dye doesn’t mean it’s going to last you any longer.
Even if it’s not outright expired three years after the manufacture date, it may still be less effective, and it’s just not worth the risk when considering all of the potential side effects.
Semi-Permanent Hair Dye
This type of hair dye has fewer chemicals in its makeup, and less of the harsh ingredients that are present in permanent hair dye.
This means that an unopened container of semi-permanent hair dye will last around two years. The timeline is the same whether it’s unopened or opened, though.
Henna Hair Dye
The average lifespan of Henna hair dye is far shorter than that of permanent hair dye or even semi-permanent hair dye.
It doesn’t tend to expire so much as it gets stale, and this happens fairly quickly once the container has been opened.
If kept in the correct conditions, most Henna hair dye products should last around three months, after which you should toss them.
How Long Should I Keep Hair Dye After It’s Been Opened?
The reaction of oxidation will start to occur when the opened container of hair dye is exposed to air, sunlight, moisture, humidity, or heat.
At this point the dye will begin to degrade. Manufacturers tend to recommend only using opened and unmixed hair dye within six weeks.
Once you’ve mixed the dye with the separate pouch of ingredients, you must use the hair dye within an hour.
Related: Does Hair Developer Expire?
Conclusion: Does Hair Dye Expire?
Hair dye does expire, just like the majority of cosmetic products. The average lifespan for permanent hair dye is three years, the average lifespan for semi-permanent hair dye is two years, and for Henna hair dye it’s closer to three months.
Using expired hair dye can have adverse side effects, some of which include hair loss, hair damage, and pain. If you are in any doubt as to whether your hair dye has expired, it’s best to throw it out.