Cocamidopropyl betaine (CAPB) is a chemical compound found in many personal care and household cleaning products. CAPB is a surfactant, which means that it interacts with water, making the molecules slippery so they don’t stick together.
When water molecules don’t stick together, they are more likely to bond with dirt and oil so when you rinse away the cleaning product, the dirt rinses away, too. In some products, CAPB is the ingredient that makes lather.
Cocamidopropyl betaine is a synthetic fatty acid made from coconuts, so products that are considered “natural” can contain this chemical. Still, some products with this ingredient may cause unpleasant side effects.
Cocamidopropyl betaine allergic reaction
Some people have an allergic reaction when they use products containing CAPB. In 2004, the American Contact Dermatitis Society declared CAPB the “Allergen of the Year.”
Since then, a 2012 scientific review of studies found that it’s not the CAPB itself that causes an allergic reaction, but two impurities that are produced in the manufacturing process.
The two irritants are aminoamide (AA) and 3-dimethylaminopropylamine (DMAPA). In multiple studies, when people were exposed to CAPB that did not contain these two impurities, they did not have an allergic reaction. Higher grades of CAPB that have been purified don’t contain AA and DMAPA and don’t cause allergic sensitivities.
If your skin is sensitive to products that contain CAPB, you may notice tightness, redness, or itchiness after you use the product. This kind of reaction is known as contact dermatitis. If the dermatitis is severe, you may have blisters or sores where the product came into contact with your skin.
Most of the time, an allergic skin reaction like this will heal on its own, or when you stop using the irritating product or use an over-the-counter hydrocortisone cream.
If the rash doesn’t get better in a few days, or if it is located near your eyes or mouth, see a doctor.
CAPB is in several products intended for use in your eyes, like contact solutions, or it’s in products that may run into your eyes as you shower. If you are sensitive to the impurities in CAPB, your eyes or eyelids could experience:
If rinsing the product away does not take care of the irritation, you may want to see a doctor.
CAPB can be found in facial, body, and hair products like:
- makeup removers
- liquid soaps
- body wash
- shaving cream
- contact lens solutions
- gynecological or anal wipes
- some toothpastes
CAPB is also a common ingredient in household spray cleaners and cleaning or disinfecting wipes.
CAPB will be listed on the ingredient label. The Environmental Working Group lists alternative names for CAPB, including:
- hydroxide inner salt
In cleaning products, you may see CAPB listed as:
- cocamidopropyl dimethyl glycine
- disodium cocoamphodipropionate
The National Institute of Health maintains a Household Product Database where you can check to see if a product you use may contain CAPB.
Some international consumer organizations like Allergy Certified and EWG Verified offer assurances that products with their seals have been tested by toxicologists and have been found to have safe levels of AA and DMAPA, the two impurities that usually cause allergic reactions in products containing CAPB.
Cocamidopropyl betaine is a fatty acid found in lots of personal hygiene and household products because it helps water to bond with dirt, oil, and other debris so they can be rinsed clean.
Although it was initially believed that CAPB was an allergen, researchers have found that it’s actually two impurities that emerge during the manufacturing process that are causing irritation to eyes and skin.
If you are sensitive to CAPB, you may experience skin discomfort or eye irritation when you use the product. You can avoid this problem by checking labels and national product databases to find out which products contain this chemical.