If you're someone who dyes your hair at home, you've probably had the experience of encountering an unopened, old hair dye box that's past the expiration date. But should you use this particular box of hair dye, or will it result in damaged hair and other unwanted side effects?
VEGAMOUR spoke with a hair color expert to determine whether you need to worry about that expired hair dye lurking in the back of your bathroom cabinet. Below, we'll cover how long hair dye lasts, whether it's ever okay to use expired hair dye and how to tell if an old box of hair dye is still safe to use.
So, does hair dye expire?
If you're rediscovering an old box of unopened hair dye, are the expiration dates important? According to vegan hair and beauty expert Liis Hainla, yes!
"Hair dye does expire," she explained. "The life span of a hair dye can vary depending on the type and how often it is used, but in general, most dyes will last about 6-12 months after opening."
If your unopened dye is in damaged packaging, or you're wondering whether to use already opened or even mixed hair dye, it's best to trash it, since the shelf life of an opened product is fairly short. But in general, box dye from many drugstore brands lasts for a longer period when properly stored.
Many hair dyes don't come with a clear expiration date printed anywhere on the box, which only adds to the confusion. As a general rule, the shelf life of hair color is typically three years, as long as it stays unopened and is kept away from heat and humidity. Properly stored, unopened hair dye usually holds its color-true performance for the length of that window. Hair color doesn't really expire so long as the dye and developer stay in separate bottles, though the formula will slowly break down over time regardless. Some brands note that opened, unmixed dye should be used within 6 weeks for the most reliable results, though this can vary by formula.
So, what actually happens if you use expired dye anyway? Expired hair dye can cause more than just a color mismatch in some cases, and Hainla said that using it can have negative effects. "After some time, hair dye can form chemicals harmful to your skin and hair, which can cause irritation or an allergic reaction," she explained.
Allergic reactions to expired permanent hair dye or semi-permanent hair dye might include a burning sensation, scalp itchiness, hair loss and other negative effects. Ingredients in hair dye like hydrogen peroxide, ammonia, resorcinol and paraphenylenediamine are more likely to cause allergic reactions the longer they sit on a shelf or in your bathroom cabinet.
"If you experience any of these symptoms after using expired hair dye, immediately stop wearing it and wash your affected areas with regular soap and water," advised Hainla.
Read More: How Long Does Hair Dye Last? Plus, 5 Tips to Make It Last Longer.
How to safely store your hair dye
Whether you buy hair color products at the drugstore or through your colorist, the storage rules are largely the same. Most hair dye manufacturers say their dyes will last past the expiration date if stored correctly, but Hainla explained that this is only true if you carefully store them in an appropriate manner.
"Hair dye can be harmful if not stored properly, so it is important to follow a few simple tips to avoid potential damage," she said. "First and foremost, make sure that the hair dye is kept out of direct sunlight or heat. This will help to prevent oxidative damage and deterioration."
Both sunlight and heat can cause your dye to change color from exposure, becoming less effective and altering the stability of the chemicals within the permanent hair color. If you use hair dye that's been overexposed to sunlight, it might not take or your hair might turn out a darker shade than you expect. To prevent this, keep any hair dyes you aren't ready to use safely tucked away in a cabinet, box or other light-blocking containers.
Hainla said exposure to oxygen could be as damaging as exposure to heat and light. An unscrewed bottle cap can cause damaging leakage. "Keep the bottle cap on tightly when you're not using the hair color product," she said. "This way, the liquid won't seep into the container and cause corrosion." If your hair dye leaks out of the bottle, it may oxidize or gel, creating a foul odor and altering the dye's color and composition.
Last but not least, Hainla said that hair dye should be kept on its own away from other chemicals in your bathroom. "Store your hair color in an airtight container away from other chemicals or foods that might contaminate it," she said. If your hair dye smells foul or has an off color, it might have mixed with another chemical and should be trashed immediately. Storing your dye this way, sealed and out of direct heat, is the simplest way to help it last a long time before you're ready to use it.
How to tell if expired hair dye is safe to use
If your expired hair dye is closed, packaged and properly stored, Hainla said that it still might be safe to use on your strands, but it's important to practice caution.
"The best way to tell if hair dye is expired is by the date printed on the bottle or squeeze tube. If that date has passed, then it's best to throw the dye away," she said.
However, just because that sell-by date hasn't arrived doesn't mean your dye is at its peak, and dye that isn't yet past its expiration date can still lose potency early depending on how it's been stored. If you have an older bottle or box on hand, Hainla said that it's important to double-check before using, even if the expiration date has yet to come.
"If your dye hasn't expired but you're still not sure whether it's okay to use, do a visual inspection of the product for signs of age, such as clumps or flaking," she recommended. "If either of these is present, it's likely that the product should not be used and instead replaced. If you don't notice anything different with the product, then it's probably safe to use." Expired hair dye may also look or smell different from when it was new, so trust your nose along with the date on the box.
Hair dye is relatively inexpensive, and old or expired hair dye can damage your hair if it's gone bad. When in doubt, it's best to skip the mystery bottle, reach for a fresh dye or leave it to professional hair color services at your salon.
Read: How to Prepare Hair for Bleaching
The best way to upkeep colored hair
Once you've got your new box of dye in hand, Hainla had plenty of recommendations for helping your hair color stay at its best for as long as possible.
"To make sure your hair color stays vibrant longer, as a hair-care expert, I suggest avoiding using harsh shampoos or conditioners that contain sulfates or parabens," she said.
Switch to a shampoo and conditioner duo that gently cleanses your hair while protecting it from environmental damage and strengthening it from the inside out. Because dyed hair tends to be lacking in moisture, you should condition every day to make sure your strands are nourished and supported, but keep your shampooing to a minimum to avoid stripping your hair of its natural oils.
"When it comes to styling, try not to overdo it by wearing too many hair products or putting excessive heat on your locks," said Hainla. Dyed hair is naturally more porous and fragile than undyed strands, so using damaging styling tools not only fades color, but it might also lead to stress, breakage and other hair problems down the line, since the chemicals in hair dye already work their way into the hair shaft during the color process.
The bottom line on using expired hair dye
Hair dye is a chemical product, and like most chemical products, it doesn't last forever. So does hair dye go bad if it's just sitting in your cabinet? It can, especially once the seal is broken.
Expired hair color is unlikely to cause serious harm, but it's not worth the gamble for a dye job you're excited about. Using expired dye can lead to uneven, brassy, or off-tone results, and it can occasionally irritate sensitive hair or scalp. Using old or expired dye tends to show its age most on light hair, sometimes pulling brassy or even hair green instead of the shade on the box.
Whether you're using boxed hair dye from the drugstore or saving leftover hair color from your last salon visit, store hair color sealed and away from heat, and once a hair dye expiration date has clearly passed, it's simplest to replace it rather than risk a color day gone sideways.
A color-safe hair care routine
Aside from not using expired hair dye, one of the best things you can do to protect your hair from damage and distress is to follow a color-safe hair care routine that supports and nourishes each and every strand. Support your locks with products that feature clean, high-performing, plant-based ingredients for optimal scalp and hair wellness. Toss that expired hair dye and start treating your strands right! Your hair will thank you later.
