Sodium Cocoyl Isethionate (SCI), Powder, 100 g

Sodium Cocoyl Isethionate (SCI) is a mild anionic surfactant derived from the fatty acids of coconut oil and isethionic acid. In a formulation, it provides cleansing and forms a rich, creamy lather, while drying out the skin less than common sulphate surfactants. It is therefore the backbone of solid shampoos, syndet bars and cleansing preparations for sensitive or children's skin.

It is processed in the water phase under heat, contains no sulphates or PEG, and in rinse-off products serves as a replacement for SLS or SLES.

Key properties

• Gentle cleansing – removes impurities and excess sebum from the skin, while disrupting the skin's own lipids less than classic sulphates. After washing, there is no tight feeling on the skin, which is especially appreciated with dry and sensitive skin.
• Creamy lather – the foam is fine, stable and dense to the touch. The natural proportion of free fatty acids in the raw material also contributes to this.
• Free from sulphates, PEG and silicones – suitable for formulations you want to label as sulphate-free.
• Readily biodegradable – according to OECD 301 methodology. The raw material holds RSPO Mass Balance certification.

Use in formulation

SCI is an anionic surfactant and is added to the water phase. It is only partially soluble in water; at room temperature it tends to disperse rather than dissolve. It dissolves at 75 – 85 °C with constant stirring. In liquid formulations it helps to first dissolve the powder in a portion of water together with an amphoteric or non-ionic surfactant (for example Cocamidopropyl Betaine or Coco-Glucoside). This combination improves solubility, the solution stays clear after cooling, and the lather is even creamier. The raw material is insoluble in oil.

The recommended dosage range is broad, 5 – 50 % depending on the product type. In liquid shower gels and shampoos, SCI stays in the lower part of the range. In solid shampoos and syndet bars it forms the main ingredient and is used up to the upper limit.

The optimal pH of the finished product is 5 – 7. SCI is an ester compound and at pH above 7, combined with prolonged heating, it gradually decomposes, loses its cleansing effect and releases fatty acids. Therefore limit heating to the time needed for dissolution and adjust pH only after cooling. Alkaline ingredients, such as traditional soap with a high pH, are not a suitable partner.

For solid products, two methods are used. The powder is mixed with the other dry ingredients, moistened with a small amount of water or glycerin and pressed into a mould. Alternatively, it is melted together with fatty alcohols (such as Cetearyl Alcohol) and vegetable butters, and the mass is poured into a mould where it solidifies.

Suitable for products such as

• Solid shampoos and syndet bars – SCI forms the backbone ingredient, gives the bar hardness and a rich lather, and the result has a skin-friendly pH that classic soap cannot achieve.
• Shower gels and facial cleansing foams – combined with an amphoteric surfactant it produces a creamy lather and reduces the overall irritation of the surfactant blend.
• Children's cleansing preparations – due to its low irritation potential it is used in formulations where skin gentleness is the priority.
• Intimate hygiene preparations – the recommended pH range of 5 – 7 meets the requirements for this type of product.
• Cleansing powders and bath fizz preparations – the powder form allows it to be added to anhydrous blends that are only activated on contact with water.

Good to know

At higher dosages in a liquid product, some of the SCI may crystallise after cooling. This manifests as cloudiness or a pearlescent appearance, sometimes also as a sediment on the bottom. Therefore test the product at lower temperatures, for example in the refrigerator, and adjust the dosage or co-surfactant ratio accordingly. Always adjust viscosity only after the product has cooled and the pH has been corrected.

The raw material is intended for rinse-off products. It does not belong in creams, serums or other leave-on preparations. Every product containing water needs a preservative; the surfactant alone does not protect the formulation.

Frequently asked questions