Are Sulfates Bad for Your Hair? An Honest NZ Salon Answer

"Are sulfates bad for my hair?" is one of the questions we field most at the basin, usually from someone who has just read a scary label or had a friend swear off them entirely. The honest salon answer is less dramatic than the internet would have you believe, and a lot more useful once you know what's actually going on. So here it is, the way our colourists explain it to clients in the chair.

What sulfates actually are

Sulfates are detergents, technically surfactants, that do the heavy lifting in most shampoos. The two you'll see on a label are sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES). They're the reason a shampoo foams up into that satisfying lather and the reason it strips oil, product and grime off your hair and scalp so effectively.

That cleaning power is genuinely good at its job. The problem is that sulfates don't discriminate. They lift away the dirt and the build-up, but they also lift away the natural oils your hair and scalp produce to stay soft and protected. For some people that's no issue at all. For others, it's the difference between hair that feels healthy and hair that feels like straw by Thursday.

So are sulfates bad for your hair?

No, not universally. This is where a lot of the online panic goes wrong. There's no solid evidence that sulfates are toxic or that they damage healthy hair the way some marketing implies. For a teenager with a naturally oily scalp and no colour in their hair, a regular sulfate shampoo is often the most practical, effective option going.

The fairer way to frame it is that sulfates are a strong cleanser, and a strong cleanser is the wrong tool for some hair. If your hair is coloured, dry, curly, fine and fragile, or your scalp gets easily irritated, that stripping action stops being helpful and starts working against you. It's not that sulfates are evil, it's that they're matched to the wrong hair.

Where sulfates and colour collide

This is the conversation we have most often, because the majority of our clients are colour clients. When you colour your hair, the cuticle (the outer layer) is opened so dye can be deposited inside the strand. Every wash with a harsh, high-foam sulfate shampoo nudges that cuticle open again and coaxes some of those colour molecules back out. Over weeks, that's how a fresh balayage drifts brassy or a vivid box of colour washes down to a memory.

To be straight with you, the science here is nuanced rather than absolute. Sulfates aren't the only thing that fades colour, sun, heat styling and hard water all play their part, and a gentle non-sulfate surfactant isn't magic. But gentler cleansing is genuinely kinder to chemically processed hair, and in our experience the difference in how long a colour stays rich and true is real enough that we recommend it without hesitation. If you've spent good money in the colour chair, washing it out with the strongest detergent on the shelf is working against your own investment. This is exactly why our colour-treated haircare picks lean sulfate-free.

Who genuinely benefits from going sulfate-free

You'll feel the upside of switching to a sulfate-free shampoo if you tick any of these:

• You colour your hair, especially blondes, balayage and any fashion or vivid shades that fade fast
• Your hair runs dry or dehydrated and feels tight, crispy or thirsty after washing
• You have curly or wavy hair, where natural oils struggle to travel down the strand and dryness is the default
• Your scalp gets irritated, flaky or itchy with regular shampoo
• Your hair is damaged or chemically over-processed from years of colour, lightening or heat

If your scalp is genuinely oily, you use a lot of heavy styling product, or your hair feels weighed down and limp, a sulfate shampoo (or at least the occasional sulfate clarifying wash) can actually be the smarter call. Sulfate-free isn't automatically "better", it's better for specific hair. Browse our full sulfate-free range if you fit the brief above, and our curly and wavy and dry and dehydrated edits if you want the picks for those concerns specifically.

The catch with cheap "sulfate-free" labels

"Sulfate-free" has become a marketing sticker, and not every bottle wearing it is doing the rest of the job well. Plenty of supermarket sulfate-free shampoos simply swap one harsh cleanser for another, or load up on silicones and waxes to fake softness while doing nothing for the actual condition of your hair. Removing sulfates is only step one.

What we want for our colour clients is a formula that cleanses gently and supports the colour and the strand at the same time. That's the gap a proper salon brand fills, and it's why we're picky about what we put on the shelf.

Why Pureology is the one our colourists reach for

If there's one range we steer colour clients toward, it's Pureology. It's the line our own colourists use and recommend, and it's built for exactly this problem rather than retrofitted to a trend.

Pureology is sulfate-free and 100% vegan, with naturally-derived ingredients and a colour-protecting formula designed to keep your colour looking salon-fresh for longer. Being honest matters to us here, so we won't tell you it's "100% natural" or "organic", because that wouldn't be true of any high-performing haircare. What is true is that it's vegan, sulfate-free and built around naturally-derived ingredients that are kind to coloured and dry hair. It's also salon-only, so you won't find genuine Pureology in Chemist Warehouse or the supermarket, which is part of why the quality stays consistent.

Prefer to shop the wider cruelty-conscious shelf rather than one brand? Our vegan haircare collection gathers the sulfate-free, vegan options we trust in one place.

How can I tell if my shampoo has sulfates?

Look at the ingredient list on the back, usually in the first few lines after water. The common ones are:

• Sodium lauryl sulfate (SLS)
• Sodium laureth sulfate (SLES)
• Ammonium lauryl sulfate or ammonium laureth sulfate

A "sulfate-free" label means none of those, but it doesn't always mean gentle. Some shampoos swap in other strong cleansers with different names. If your hair feels just as squeaky and stripped after switching, that's the likely reason.

The simplest route is a brand that states it plainly. Pureology says its shampoos are free of sulfates, and Hydrate Shampoo ($58.08) is the one most of our colour clients go home with.

Do I still need a clarifying wash if I go sulfate-free?

Sometimes. Sulfate-free shampoos clean gently, which is the point, but they don't always shift heavy build-up from dry shampoo, styling products, sunscreen or minerals in the water.

Signs you need a deeper cleanse: roots that feel coated a day after washing, hair that won't hold a style, or colour that looks dull even though you're doing everything right.

For oily roots with dry lengths, Kérastase Spécifique Bain Divalent ($57.12) is designed to purify the scalp without drying the rest. For build-up from water, L’Oréal Professionnel Metal Detox ($58.08) is what we use. Once a fortnight is plenty for most people, then back to your usual shampoo.

Kérastase or Pureology for coloured hair: which suits my budget?

Two ways, choose by budget. Two colour routines we use, at slightly different prices.

	Kérastase Chroma Absolu	Pureology Hydrate Sheer
Shampoo	Bain Riche Chroma Respect $57.12	Hydrate Sheer Shampoo $58.08
Conditioner	Fondant Cica Chroma $70.56	Hydrate Sheer Conditioner $58.08
Total	$127.68	$116.16

Pureology suits you if you want a brand that states its shampoos are sulfate-free and vegan, at a lower total. Kérastase suits coloured hair that needs more care and shine, with a gloss treatment in the same range to add later.

The honest bottom line

Sulfates aren't a villain, they're a tool. They're a strong cleanser that suits oily, robust, uncoloured hair and works against dry, curly, fragile or colour-treated hair. If you've invested in your colour or your hair runs dry, a quality sulfate-free shampoo will earn its place fast. If your scalp is oily and your hair is uncoloured, you may not need to change a thing.

If you're not sure where your hair sits, that's genuinely what we're here for. Ask us next time you're in the chair, or message the salon and we'll point you to the right shampoo for your hair rather than the loudest label.

As a real Queenstown salon that gets genuine Pureology direct from L'Oréal NZ, we ship salon haircare NZ-wide with free shipping over $75. Shop sulfate-free at Crew and give your colour, and your hair, the gentler wash it's been asking for.

Frequently asked questions

Are sulfates actually bad for your hair?

Not universally. Sulfates are a strong cleanser that suits oily, robust, uncoloured hair, but they can dry out and fade colour-treated, curly, dry or fragile hair by stripping natural oils. It depends entirely on your hair type, not on sulfates being toxic.

Do sulfates fade hair colour?

They can contribute to it. Harsh sulfate shampoos help open the hair's cuticle, which lets colour molecules wash out faster over time. The science is nuanced rather than absolute, but gentler sulfate-free cleansing is kinder to coloured hair and helps your colour stay rich for longer.

Who should switch to a sulfate-free shampoo?

Anyone with coloured, dry, curly, damaged or fragile hair, or an easily irritated scalp, tends to benefit most. If your scalp is oily, your hair is uncoloured or it feels weighed down, a regular sulfate shampoo can still be the better choice.

Is Pureology sulfate-free and vegan?

Yes. Pureology is sulfate-free and 100% vegan, made with naturally-derived ingredients and a colour-protecting formula. It is the range our colourists reach for, and it is salon-only, so you won't find genuine Pureology in supermarkets or Chemist Warehouse.

Does Crew ship sulfate-free haircare across New Zealand?

Yes. Crew is a Queenstown salon that gets genuine Pureology direct from L'Oréal NZ, alongside other salon brands, and we ship haircare NZ-wide with free shipping on orders over $75.

Is sulfate-free shampoo good for oily hair?

It can be, but it may take a couple of weeks for your scalp to adjust, and some very oily scalps never feel quite clean enough. If that's you, alternate: a sulfate-free shampoo most washes to protect your lengths and colour, and a purifying scalp shampoo once or twice a week. Massage the scalp properly and rinse well.

Why doesn't sulfate-free shampoo lather much?

Sulfates are what make shampoo foam up, so taking them out means a softer, smaller lather. It's still cleaning. Wet your hair thoroughly first, rub the shampoo between your hands with a little water, and focus on the scalp. On the second wash, if you do one, you'll usually get more foam because the oil has already been lifted.