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What Is SLS and Why Should You Avoid It in Hair Color?

by Madison Reed March 12, 2024


Image by Madison Reed

What Is SLS and Why Should You Avoid It in Hair Color?

SLS stands for sodium lauryl sulfate, a common ingredient found in products like soaps, toothpastes, and hair color. As you might expect, a chemical that is used for so many different purposes might not be the best for your hair. Read on to find out why!

So, What Is Sodium Lauryl Sulfate?

Sodium lauryl sulfate, known as SLS, is a compound found in cosmetics and cleaning products. It is responsible for foaming.


While SLS has been deemed “safe to use” by organizations such as The Cosmetic, Toiletry and Fragrance Association (CTFA) and The Cosmetic Ingredient Review Panel (CIR), it doesn’t mean that it’s perfectly fine.


SLS is a surfactant, meaning it lowers the surface tension between ingredients and creates the lather often associated with shampoo and other hair products. However, SLS is also known to strip the protein from hair, depleting the hair and scalp of beneficial protective oils. Products containing harsh surfactants like SLS are also known to contribute to color fade. In severe instances, SLS can also irritate the scalp, causing redness, dryness, and itching.

What Is Sodium Laureth Sulfate, Then?

Sodium lauryl sulfate is often mistaken for sodium laureth sulfate – a substance that is derived from SLS, and commonly referred to as SLeS or SLES.


How is sodium laureth sulfate different from sodium lauryl sulfate? Sodium laureth sulfate is a gentler alternative to sodium lauryl sulfate. 


We never use sodium lauryl sulfate in our products, opting instead to use sodium laureth sulfate, which is gentler on the skin. Sodium laureth sulfate is also used in our formulas to ensure a full, even application of color, and total removal of color from the scalp and hair while rinsing.

Why Should You Avoid SLS in Hair Color?

The problem with SLS in hair color is that you keep the color on your scalp for quite some time – long enough to cause irritation. When used regularly, the SLS compound may even lead to dandruff and dry scalp


In addition to irritating and drying your scalp, SLS can affect the hair itself. It’s can strip your hair of its natural oils, which can result in weaker hair, hair that’s more prone to breakage.


This is exactly why we make sure that SLS doesn’t make it on to our hair color ingredients list. But it’s not just about hair color – there are other hair care products that may also contain this substance.

Permanent hair color without SLS

Check out our SLS-free permanent hair colors!

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Which Products Are Likely to Contain SLS?

So, you know what the deal is with SLS. Now, let’s talk about the products that may include it. After all, you want to know what to watch out for, right? But before we discuss that, let’s look at how SLS is actually labeled on hair care products. This way, you’ll know exactly how to find the best sulfate-free shampoos and conditioners on your own!

  • SLS

  • Dodecyl Sulfate, Sodium

  • Irium

  • Lauryl Sulfate, Sodium

  • Sodium Dodecyl Sulfate

  • Sodium Lauryl Sulfate

  • Sulfate, Sodium Dodecyl

  • Sulfate, Sodium Lauryl


Now, let’s list the hair care products that might contain SLS:

  • Hair Color

  • Shampoos

  • Shower Gels (while not exactly a hair care product, many men use 3-in-1 gels, so they should check these products as well)

  • Bleaches

  • Hair Styling Products


As you can see, SLS is present in nearly every hair care product you use. That's why we recommend Madison Reed’s products. Instead of painstakingly scrutinizing every shampoo, bleach, and dye, when you choose from our selection of hair color and care products, you can be confident that they are SLS free. It's a simpler, more efficient approach – because coloring your hair should be fun!

At home color delivery kit without SLS

Try our at-home membership and get SLS-free hair color auto-delivered to your home!

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Do You Really Need to Stress Out About SLS?

Did you discover that your current hair color or shampoo contains SLS? Then you should think about changing it.


While sodium laureth sulfate isn’t that bad overall, sodium lauryl sulfate is. Still, if you used a product containing this ingredient once or twice, nothing too bad should happen – perhaps, you won’t even feel any difference. The problems start only when you expose your hair to SLS regularly.


Dandruff or dry scalp won’t appear immediately after using a product with SLS, and neither will skin irritation. But the more often you apply these products on your scalp, the more likely such conditions are to appear. So, if you haven’t experienced any problems yet, there’s nothing to stress about – just switch to products that are free of harsh ingredients and it should be fine!

The Takeaway

So, what is sodium lauryl sulfate and what is sodium laureth sulfate? The former is a compound used for foaming in cleaning and hair care products, and the latter is a less harsh alternative to it. You should try to avoid SLS, as it might cause scalp irritation, dry scalp, or even hair loss. How do you do that? By choosing products made with ingredients you can feel good about – such as Madison Reed shampoos, conditioners, and hair color!

Did you like this article? You may also want to read: All About Ammonia-Free Hair Color