Sodium Carboxymethyl Starch

What is Sodium Carboxymethyl Starch?

Sodium carboxymethyl starch is a chemically modified derivative of natural starch, a polysaccharide extracted from sources like corn, wheat, or potatoes. The modification involves attaching carboxymethyl groups using sodium hydroxide and chloroacetic acid, rendering it water-soluble and highly absorbent. In cosmetics, it belongs to the category of polysaccharide thickeners and stabilizers, commonly found in creams, lotions, serums, and makeup products. It functions by swelling upon water absorption to increase viscosity, bind ingredients together, reinforce emulsion structures against separation, form protective films for better product adherence, and control flow properties for optimal application and feel. This versatile ingredient supports formulation integrity without altering sensory qualities significantly.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Binder
Helps hold solid ingredients together to form cohesive tablets, compacts, or sticks, improving pressability, integrity, and wear of the finished product.
Emulsion stabilizer
Improves emulsion robustness by preventing droplet coalescence and phase separation, often by thickening, structuring, or strengthening the interfacial layer.
Film former
Creates a continuous film on skin or hair to improve wear, water resistance, transfer resistance, shine, or hold in sunscreens, makeup, and styling products.
Viscosity controlling agent
Adjusts thickness to the desired level for stability and usability, improving dispensing, suspension, and texture across many formulation types.
Binding
Provides cohesion by helping ingredients stick together, improving the strength and integrity of pressed powders, tablets, or solid bars.

Benefits

Improves emulsion stability to prevent separation and extend shelf life.

Enhances product texture for smoother application and better spreadability.

Forms a lightweight film to boost wear and water resistance in formulas.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Individuals seeking stable, long-lasting skincare emulsions.
People with rare starch-derived allergies.
Users preferring mild, plant-based texturizers in daily routines.
Individuals sensitive to modified polysaccharides.
Those with normal to dry skin benefiting from improved hydration retention.
Those preferring strictly unmodified natural ingredients.

Safety Notes

  • Considered safe for cosmetic use by regulatory bodies with low hazard ratings.
  • Non-comedogenic, unlikely to clog pores based on available data.

Frequently Asked Questions about Sodium Carboxymethyl Starch

What is sodium carboxymethyl starch?

A water-soluble starch derivative from plants, used to thicken and stabilize cosmetic products.

Is it safe for sensitive skin?

Yes, it has low irritation potential and is suitable for most skin types.

Does it help with product texture?

Yes, it controls viscosity for smoother feel and better application.