Is Hair Dye Harmful to Your Health?

Sable Yong


As someone with naturally dark hair, I’ve had my share of struggles with hair dye chemicals. If I want my hair to be anything other than black, it requires serious work—we’re talking hours of bleaching and toning in the salon, and that’s before the color is even applied. But the work is worth it: I’ve been silver, blue, every shade of pink and even platinum blonde. No matter the shade, every time I color I’m met with an onslaught of fumes that make my eyes water and occasionally I receive a chemically scorched scalp. Pain as a means to beauty is no foreign concept, but after a while one starts to wonder “What are all these chemicals doing to my health?”

So, I went straight to the source: who better to talk to about the potential health hazards of hair dye chemicals than professional colorists?

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Is hair dye actually dangerous?
Over all, no—hair dye is not harmful, but we should clarify what we mean by ‘harmful.’ “Harmful is a tricky word as it does not necessarily mean dangerous when used correctly. Many things in nature can be harmful; it’s the way man uses them that makes them dangerous. There is a need and reason for each of these chemicals,” says Davines Color Educator, Naomi Knights, who considers herself a “sustainable colorist.” When used by a trained professional who takes the correct safety precautions, hair dye is generally not hazardous to your health—the problems usually arise when someone who isn’t sure what they’re doing gets a hold of them, or uses them for an unintended purpose.

The ingredient breakdown.
That said, there are certainly some ingredients that have raised questions over the last few years. Will Francis, a colorist at Sally Hershberger Downtown NYC, is quick to name formaldehyde and coal tar as two potentially harmful components. Formaldehyde, very popular in the dye formulas of yore, is a hardcore preservative (it’s the same thing used to embalm dead bodies) and known carcinogen. Many hair dyes no longer use it as an ingredient, and when it is used, it’s present in such minute quantities that your dye job isn’t going to give you cancer—so don’t be too alarmed.

As for coal tar, it’s used as a coloring agent in some dyes, and while it’s carcinogenic in large enough quantities, at concentrations under 5% it’s considered safe by the FDA. Coal tar even has beneficial effects: it’s the active ingredient in some dandruff shampoos, and it can be used to treat psoriasis and seborrheic dermatitis.

Ammonia and Para-phenylenediamine (PPDs), both common ingredients in modern hair colors, are currently touted as the “dangerous” ingredients in hair dye. They’re rumored to cause dermatitis, swelling, itching, and blistering, but Naomi says that these fears are largely over-hyped. You’d need to color your hair multiple times a day for a few lifetimes to see any lasting negative effects from PPDs or ammonia.

What exactly should we be concerned about when it comes to hair dye?
Should we wear protective nose and mouth masks when we get our hair colored? Our experts say no.

“Ammonia inhalation is what most of my clients are concerned about,” Knights says, “But they never consider that we have ammonia occurring naturally in our bodies. People especially have concerns about this when they are pregnant or trying to get pregnant. I always leave that up to them and their doctors. I worked with dye up until my ninth month without any issues!”

Okay, so our lungs are safe. What about our skin? Will we encounter lasting health risks from piling chemicals onto our scalps? It turns out that’s unlikely.

Hair is made of keratin, just like your skin. But whereas hair simply takes the damage caused by hair dye chemicals, skin is able to repair itself. It’s constantly rebuilding and protecting you from any potentially harmful substances, so if you’re healthy, it’s very unlikely that any hair dye chemicals will be absorbed through your skin. PPDs are more of a concern on the skin, though—some people may experience allergic reactions when dye comes into contact with their skin. These reactions are generally mild, and can be avoided by doing a patch test before coloring hair to check skin sensitivity.

What’s the difference, safety-wise, between professional and box dyes?
Our professionals were united on this: salon dyes are both better and safer for you due to their higher quality ingredients. Francis credits the quality of the dyes formulated for salons as a key factor, while Knights adds that salon dyes contain more elements to protect your hair and skin while preserving the color.

The main difference between salon vs. drugstore dyes has to do mostly with the pigment to protective ingredient ratio. Boxed dyes often contain lots of pigment but not so much in terms of ingredients needed to preserve and protect, so your color is more likely to fade very quickly. And because there aren’t as many nurturing ingredients, you may find that your skin reacts strangely to box dyes—almost everyone has a story about a swollen faces or an itchy scalp that happened after using drugstore dye. So why is this?

Sadly, it all comes down to the almighty dollar. “Cost is always an issue in situations like this,” says Knights. “Professional products contain less pigments and more ingredients to protect, nourish and restore the hair structure. Compare that to box color, which is very cheap, so the extra ingredients used for protection are deleted. Brands also increase the amount of pigment, because the consumer may not know how to properly apply the color.” All of this equals a potentially disastrous at-home dye experience.

And if you want to take no chances, Davines—which is only available in salons—offers ammonia and PPD-free hair dye. If you’re looking for that in the drugstore, you may be out of luck.

What kinds of precautionary measures can be taken before getting hair colored?
Better safe than sorry (or hairless), so believe it or not, those “patch test” recommendations on your box dye really go for ALL hair color.

“The absolute best way to protect yourself is to come in for a consultation at least 48 hours before your coloring service to get a patch test,” Knights tells us. A patch test is when the hair dye is applied to a patch of skin—usually your forearm, inner elbow or behind the ear—to see if your skin reacts to it before you pour it all over your head.

But that’s not all: depending on the condition of your hair and the color you’re going for, your colorist may snip some strands from an unnoticeable section of your head and apply the dye beforehand to check if your hair is too compromised to handle it. It’s the same ethos as “measure twice, cut once;” and this way you won’t end up with a horrible allergic reaction or chemical haircut. And if you’re trying to avoid as many harsh chemicals as possible, Francis suggests semi-permanent vegetable hair dyes for a healthier alternative.

You can also time your colorist appointments well. Knights says that the worst time to book that dramatic hair color change is when you’re hormonally charged (aka ovulating), hungover, or generally in a sensitive state. After all, it does require a bit of discipline and clear-headedness to sit through a dye job. And if you’re pregnant, have existing skin concerns or respiratory issues, you should definitely consult your doctor before stepping into the salon for any chemical treatment—including color.

How can you find the least harmful dyes?
Look for labels that are subject to EU health and safety guidelines. European cosmetics brands are under the scrutiny of the European Union, which is very strict about chemical use—in many ways, they’re far more vigilant than the US-based FDA. Hair formulas in particular are always changing and being tested because of this, only allowing 10% of the max percentage of a chemical’s safety to use (so if something is safe at 50% or lower, only 5% of it will be allowed). It pays to look into brands and lines that follow EU guidelines if you’re aiming for the least harmful hair dye chemicals.

What have we learned?
In the hands of experts, hair dye chemicals are as safe as it’s possible for any chemicals to be. I may never be able to go platinum again without my scalp turning into a burn-addled mess, but at least I won’t also worry about a dramatic dye job giving me cancer.

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