This is a common ingredient in all kinds of cleansing products from face and body washes to shampoos and foam baths. Cocamidopropyl betaine helps to stabilize bubbles, making cleansers, shampoos, and body washes sudsy.

This mild, synthetic ingredients combines well with other cleansing agents and surfactants making it easy to use in formulas. Another plus, it’s biodegradable even thought it’s artificial.

There is some concern it is associated with irritation and allergic contact dermatitis. However, when it’s used in wash off, instead of leave on products, this is less of an issue.

Cocamidopropyl Betaine (Wikipedia)

Cocamidopropyl betaine (CAPB) is a mixture of closely related organic compounds derived from coconut oil and dimethylaminopropylamine. CAPB is available as a viscous pale yellow solution and it is used as a surfactant in personal care products and animal husbandry. The name reflects that the major part of the molecule, the lauric acid group, is derived from coconut oil. Cocamidopropyl betaine to a significant degree has replaced cocamide DEA.

Lauramidopropyl betaine

Lauramidopropyl betaine, the major component of cocamidopropyl betaine
Names
IUPAC name {[3-(Dodecanoylamino)propyl](dimethyl)ammonio}acetate
Other names 2-[(3-Dodecanamidopropyl)dimethylaminio]acetate
Identifiers
CAS Number	61789-40-0 Y
3D model (JSmol)	Interactive image Interactive image Interactive image
ChemSpider	19106 Y
ECHA InfoCard	100.057.308
EC Number	263-058-8
PubChem CID	20280
UNII	5OCF3O11KX N
CompTox Dashboard (EPA)	DTXSID6028072
InChI InChI=1S/C19H38N2O3/c1-4-5-6-7-8-9-10-11-12-14-18(22)20-15-13-16-21(2,3)17-19(23)24/h4-17H2,1-3H3,(H-,20,22,23,24) Y Key: MRUAUOIMASANKQ-UHFFFAOYSA-N Y InChI=1/C19H38N2O3/c1-4-5-6-7-8-9-10-11-12-14-18(22)20-15-13-16-21(2,3)17-19(23)24/h4-17H2,1-3H3,(H-,20,22,23,24) Key: MRUAUOIMASANKQ-UHFFFAOYAL
SMILES CCCCCCCCCCCC(=O)NCCC[N+](C)(C)CC([O-])=O CCCCCCCCCCCC(=O)NCCC[N+](C)(C)CC(=O)[O-] [O-]C(=O)C[N+](CCCNC(=O)CCCCCCCCCCC)(C)C
Properties
Chemical formula	C19H38N2O3
Molar mass	342.524 g·mol−1
Appearance	Clear to slight yellow liquid
Density	1.05 g/cm3
Melting point	< −10 °C (14 °F; 263 K)
Boiling point	> 100 °C (212 °F; 373 K)
Solubility in water	Soluble
Viscosity	< 100 cP (30°C)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H400
NFPA 704 (fire diamond)	2 1 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references