Betaine (Cocamidopropyl Betaine or Trimethylglycine) is an amphoteric surfactant and skin-conditioning agent with a 5% solution pH of 4.0–6.0. In personal care formulations, Betaine serves as a secondary mild surfactant and foam booster that enhances the mildness, conditioning performance, and skin feel of primary surfactant systems. It reduces the eye and skin irritation potential of stronger surfactants (such as SLES), making it a key ingredient in baby care, sensitive skin, and conditioning cleansing formulations.
Applications:
- Shampoos (secondary mild surfactant, foam booster, conditioning agent for hair cleansers)
- Body Wash (mildness enhancer, skin-conditioning co-surfactant)
- Baby Care (ultra-mild co-surfactant for baby shampoos and washes — tear-free formulations)
- Facial Cleansers (gentle conditioning cleanser for sensitive skin formulations)
Key Features & Benefits:
- pH 4.0–6.0 (5% solution) – compatible amphoteric surfactant
- Reduces irritation potential of primary surfactant systems
- Excellent foam boosting and stabilising properties
- Skin-conditioning – leaves skin feeling soft and smooth
- Essential in baby, sensitive, and conditioning cleansing formulations
Cocamidopropyl betaine is not trimethylglycine
In personal care, “betaine” usually means cocamidopropyl betaine (CAPB), an amphoteric surfactant made from coconut fatty acids. Trimethylglycine (betaine anhydrous) is a different substance, an amino acid derivative used in food, supplements and as a skin humectant; it is not a surfactant. Make sure the INCI name on the certificate matches the material your formula needs.
Impurities to control
CAPB is made in two steps, and two by-products, amidoamine and dimethylaminopropylamine (DMAPA), are known skin sensitisers. Better grades keep both low; ask for the results. CAPB is usually supplied as a solution of about 30% active with sodium chloride from the process, and that salt affects how much extra salt your formula needs for viscosity.
Formulation role
CAPB is used as a secondary surfactant with SLES or Alkyl Polyglucoside 1214: it boosts foam, raises viscosity and reduces the irritation of the primary surfactant. Its pH is adjusted with citric acid in the finished product.
What to ask for on the certificate of analysis
- INCI name (cocamidopropyl betaine)
- Active content, solids, sodium chloride and pH
- Amidoamine and DMAPA, with the method
- Free fatty acids and glycerin
- Heavy metals, as required for cosmetics under the ASEAN Cosmetic Directive
- Microbiology (total aerobic count, yeast and mould) for water-containing grades
- Batch number, manufacture and retest dates; safety data sheet (SDS)
