Common Name(s): Potassium myristyl aspartate,potassium soft soap,liquid soap cleanser

CAS Number: N/a

DESCRIPTION

What It Does: Potassium myristyl aspartate cleanses the skin and hair by micellising oils, sebum, and dirt for rinsing away with water, while the potassium fatty acid salt provides a creamy, moisturising lather that leaves skin feeling soft rather than stripped.

Why It's Used: Formulators choose potassium myristyl aspartate to deliver the rich, luxurious lather and skin-compatible cleansing characteristic of pure soap chemistry in a liquid format. the potassium counterion is preferred over sodium in liquid cleansers because it produces a water-soluble paste or liquid rather than a solid bar, enabling pump-dispenser formats with excellent rinse performance and a creamy skin feel.

How It Works: Potassium myristyl aspartate works through classic soap surfactancy: the fatty acid carboxylate tail is lipophilic and embeds into oil droplets or sebum, while the potassium carboxylate head group is hydrophilic and faces the water phase. these fatty acid soap molecules self-assemble into micelles around oil droplets, allowing them to be rinsed away. the potassium counterion (k⁺, ionic radius 1.38 å) is larger than sodium (na⁺, 1.02 å), which disrupts the tight crystal lattice of sodium soap and produces a softer, more water-soluble, and more skin-compatible product at room temperature.

Typically Found In: Liquid soaps,shaving creams,body wash

TECHNICAL DETAILS

Primary Category: Active ingredient – cosmetic active

Secondary Functions: Skin conditioning

Application Areas:

Typical Concentration Range: 5%–30%

SOURCING & ETHICS

Vegan Status: Conditional

Halal Status: Yes

Source Notes: Commercially produced for cosmetic use. verify vegan/halal status with supplier.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 0/5 – non-comedogenic

Sensitivity Concerns: Well-tolerated by most skin types.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Good safety profile at recommended concentrations. ewg score: 1–2.

Works Well With: Standard skincare actives

Avoid Combining With: No known significant incompatibilities

SCIENTIFIC NOTE

Potassium vs sodium soap physical state: na⁺ forms a high-melting crystalline fatty acid salt (hard bar soap, krafft temperature >50°c); k⁺ forms a lower-melting soft paste/liquid from the 35% larger counterion disrupting crystal lattice packing. this physical state difference from counterion size explains why liquid soaps use koh saponification while bar soaps use naoh — the identical fatty acid backbone in completely different physical forms purely from the metal counterion.

Last Verified: Cosing database,potassium myristyl aspartate potassium soap chemistry review

Primary Sources: 2026-03-12