Common Name(s): 3-aminopropane sulfonic acid,3-aps,beta-alanine sulfonic acid,taurine analog

CAS Number: 3687-18-1

DESCRIPTION

What It Does: Conditions hair and skin, reduces static, and improves manageability.

Why It's Used: A taurine-analog amino sulfonic acid providing hair and skin conditioning; the zwitterionic structure (amine + sulfonate) gives excellent affinity to keratin surfaces.

How It Works: Zwitterionic character at physiological ph enables strong adsorption to hair/skin keratin; amino group provides cationic character for anti-static function; sulfonate provides water solubility and retention.

Typically Found In: Hair conditioners,anti-static hair products,skin conditioning serums,cleansing formulas

TECHNICAL DETAILS

Primary Category: Active ingredient – conditioning

Secondary Functions: Hair conditioning,anti-static,skin conditioning

Application Areas:

Typical Concentration Range: 0.5%–5%

SOURCING & ETHICS

Vegan Status: Yes

Halal Status: Yes

Source Notes: Synthetic amino sulfonic acid; related to taurine chemistry.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 1/5 – low

Sensitivity Concerns: Very mild; amino sulfonate structure is well tolerated.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Good safety profile. ewg score: 1.

Works Well With: Betaines,quaternary ammonium conditioners,humectants,amino acids

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

3-aminopropane sulfonic acid is a structural analog of taurine (2-aminoethane sulfonic acid) with an extended propane spacer; amino sulfonates combine zwitterionic conditioning with inherent surface activity; cas 3687-18-1.

Last Verified: Cosing database,inci dictionary,cas 3687-18-1

Primary Sources: 2026-03-27