SLSa / Sodium Lauryl Sulfoacetate – 10 BEST FAQ like what is SLSa powder? how does it look like? and many more

September 25, 2020
what is slsa powder

What is SLSa Powder?

SLSa, scientifically known under INCI (International Nomenclature for Cosmetic Ingredients) as Sodium lauryl sulfoacetate, is a mild cleansing agent and the active ingredient in many cosmetic products due to its versatile properties as a surfactant and foaming agent. Surfactants are added to cosmetics for their ability to remove oil and dirt particles from the hair and skin. Foaming agents, on the other hand, are added to soaps to create lather and bubbles.

What are SLSa physical and chemical properties?

At the molecular level, SLSa has two parts. The first of these is a negatively charged ‘head’ made up of a sulfoacetate and sodium ion. The second part is a long chain of carbons that have no charge. While the water-soluble ‘head’ is pulled towards the water, the water insoluble ‘tail’ is pushed away from it and towards the oil. This is what makes it a surfactant: it can bridge the gap between water and oil.

This property also makes SLSa good emulsifier as it can decrease the surface tension between the oil and water, which in turn causes the oil to rinse off as if it was soluble in water. SLSa is soluble in water and most organic solvents even though most carbon based (organic) molecules are insoluble in water. In water, it has a pH of 6.3 – around the acidity of coffee or milk. Depending on the concentration of SLS-a in the final product, the pH can range from 5.0 to 7.0. Human skin has a natural pH of 4.5 to 6.2, which makes it slightly acidic. Skincare products usually have a pH of 5.0 to 7.5 in order to maintain this balance. Fortunately, SLS-a is in the middle of that range. Some cleansers can have pHs over 9.0 or below 5.0, both of which are quite bad for the skin.

SLSa is also a larger molecule than SLS and therefore cannot penetrate the skin in order to irritate it. SLSa is non-hygroscopic. This means that it does not absorb water from the air around it. It is stable in hard water and in solutions with pHs ranging from 5.0 to 8.5, which makes it excellent for many kinds of products. It is also resistant to hydrolysis, meaning it won’t react with water even at high temperatures.

Is SLSa a Sulfate?

Many shampoos and conditioners are advertised as ‘sulfate free.’ Sulfates are notorious for the way they dry out and irritate skin. SLS-a is often confused with the notorious sulfate SLS – also known as sodium lauryl sulfate – because the two have very similar names. While SLS-a does contain sulfur, it does not have the sulfate ion. Instead, the sulfur in SLS-a takes the form of a sulfoacetate. Sulfates have four oxygens, one of which is bonded to the carbon tail. Sulfoacetates have five oxygens, one of which is bonded to the carbon ‘tail.’ Unlike SLS, SLSa is much gentler on the skin and doesn’t leave it reddened or irritated.

What does SLSa look like?

 At room temperature, it is a very fine free-flowing white powder with a characteristically detergent-like odor. It is very soluble in water and most other solvents. It has a density of 1.33 g/cm3.

How is SLSa made?

 It is derived from plants, unlike synthetic sulfates such as sodium lauryl sulfate are more damaging to the skin as they dry out the skin. More specifically, SLSa is made from coconut and palm kernel oil. This makes it sustainable, natural, and biodegradable.

what is slsa powder
Shampoo Bar made from SLSa
How is SLSa used?

            SLS-a is used in soaps, shampoos, gels, foams, and many more cosmetic products due to its gentle cleansing, moisturizing, and foaming properties.

            In soaps and shampoos, it foams up to create a rich lather. It is especially popular for bath bombs, bath truffles, bath salts and other bath preparations due to the combination of its solubility in water and ability to make a veritable blanket of large, long-lasting bubbles. This improves the cleaning abilities of the rest of the formulation without leaving behind dry skin. It makes hair and skin softer to the touch without causing the dryness or irritation of SLS or other synthetic surfactants.  Better yet, it is good for even the most sensitive of skin types and the most damaged hair.

How strong is SLSa ?

            SLSa has an active surfactant level of 64%. As a result, almost half of it is active, while the remaining portion is filler. It is safe to use in concentrations of up to 70% without irritating the skin. In liquid products, it is normally used at a concentration of 1-4% as it can increase viscosity. In solid and paste products, it is used at a concentration of 50-70% by mass.

What can I use as substitutes for SLSa?

            One common question is what to do if for whatever reason, you can’t obtain SLSa. Keep in mind that SLSa is more gentle than most solid surfactants. A replacement may be more irritating.  The most common replacement is SCI or sodium cocoyl isethionate. Note that SCI is insoluble in water. Other options include sodium coco sulfate (SCS), and sodium C14-16 olefin sulfonate (Bio-Terge AS90).

Is SLSa safe to use?

            Yes. SLSa is very gentle on the skin when used properly. It is non-toxic unless swallowed and a nonallergen. However, one should remember to be careful when working with fine powders as they can be dangerous if inhaled. Always wear an N95 or other particulate-filtering mask when using the powdered form. If disturbed, it can rise up in combustible clouds of dust. Keep away from heat, oxidizing agents, and open flame. Otherwise, it is stable at standard storage and transport conditions. Take care to ensure it does not come into contact with the eyes, as it can cause irritation. If it does come in contact with the eyes, rinse them with water for fifteen minutes. In the event that irritation persists, seek medical attention. Store any unused SLSa in a cool, dry, and dark area. It will keep for up to two years.

Where is to buy SLSa in India?

Amazon Affiliate Link –

Bathsutra Soap Supplies –

Similar Blogpost

SCI – Sodium Cocoyl Isethionate

Watch Recipe with SLSa powder

Shampoo Bar Recipe

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    Dr. Namrata Yadav
    September 28, 2020 at 12:41 pm

    Loving this series on surfactants, so informative and interesting. Looking forward to more

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    Nita jain
    October 4, 2020 at 9:25 am

    Thanks a ton

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    LM Regalado
    October 17, 2021 at 10:07 pm

    Since SLSa is skin friendly, can I use it in laundry detergent instead of SLS or SLES?
    If so, what would be the ratio or how many grams? Thank you

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