Cocamidopropyl betaine, or CAPB for short, is an ingredient in many personal care products, including some brands of shampoo, body wash, and soap. Manufacturers also use it to formulate household cleaners and laundry detergent.

CAPB is a surfactant that comes from coconut oil. Surfactants are substances that lift oil and grease, allowing for easier removal.

Although CAPB poses a low risk of skin irritation, it is a safe ingredient for most people. There is concern that it may be harmful to the environment, though.

This article looks at cocamidopropyl betaine in more detail, including its properties, uses, safety, and environmental impact.

Close-up of light reflecting in bubbles created by cocamidopropyl betaine.Share on Pinterest
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CAPB is a surfactant and foam enhancer that is present in many personal care products. It combines a mixture of fatty acids that come from coconut oil with propylene glycol, which is a synthetic compound.

Manufacturers use CAPB in products that clean the skin and hair, due to its ability to lift and remove oil. Some companies use CAPB as a replacement for sodium lauryl sulfate (SLS), which is also a surfactant and foaming agent. Some people find SLS a harsh and drying surfactant, whereas CAPB can be milder.

CAPB has several properties that make it useful in various personal care and household products:

  • Surfactant: CAPB allows water and oil — two substances that usually repel each other — to interact. This makes it possible to remove oil with water, lifting it from the skin or hair.
  • Foam enhancer: In shampoos and body washes, CAPB can help create a rich lather when it comes into contact with water.
  • Thickening: CAPB adds viscosity to products, making them thicker and creamier. This is useful in products such as hair conditioners, as it makes them less likely to drip.

Some products that may contain CAPB include:

  • body wash
  • facial cleanser
  • shampoo
  • conditioner
  • hair styling products
  • hair coloring kits
  • shaving cream
  • mouthwash
  • makeup remover
  • liquid soap
  • toothpaste
  • household cleaners
  • laundry detergent

With proper use, products containing CAPB should be safe for most individuals. CAPB is a mild ingredient that manufacturers may include in products for babies and infants.

However, it is not suitable for products that remain on the skin. Leaving CAPB on the skin may result in irritation.

The Environmental Working Group (EWG) notes that CAPB is not linked to cancer, developmental toxicity, or reproductive toxicity. However, there is concern that it may cause skin sensitization through contact.

It is best to perform a patch test before applying any new product to a large area of the skin.

Although CAPB is usually well-tolerated, some individuals may experience side effects.

Skin discomfort

Some people are sensitive to CAPB and may experience the following skin-related symptoms after using it:

  • tightness
  • itchiness
  • inflammation
  • rash

Often, these symptoms resolve on their own when the individual stops using the product. However, if they do not improve, it is advisable to seek medical attention.

Some evidence suggests that people with atopic dermatitis, the most common type of eczema, may be sensitive to CAPB. Due to this, people with eczema may wish to avoid using products that list it as an ingredient.

Eye irritation

Some products that could come into contact with the eyes, such as contact lens solution, contain CAPB. People who are sensitive to CAPB may notice that their eyes become painful, itchy, or red when they use these products.

If these symptoms occur, it is important to rinse the eyes and the surrounding skin under clean running water. A person should speak with a doctor if the irritation does not resolve.

Allergic reaction

Scientists initially believed that CAPB was a potential allergen. However, according to a 2012 review, it is impurities from the manufacturing process that may cause reactions. These irritants are amidoamines and 3,3-dimethylaminopropylamine.

Products that do not contain these impurities appear not to cause the same allergic reactions. However, it is difficult to know which products do and do not have these impurities. Therefore, it is best for people with these allergies to avoid CAPB.

CAPB may have a negative impact on the environment. The EWG notes the concern that CAPB may be toxic to aquatic life. Similarly, the National Library of Medicine lists it as very toxic to aquatic life.

However, in 2013, a scientist conducted an aquatic risk assessment and found that CAPB was safe for the aquatic environment. Also, because water treatment plants process wastewater and CAPB degrades extensively, it does not accumulate in the environment.

Overall, more research is necessary to understand whether CAPB is harmful to the environment and, if so, how harmful it is.

As CAPB contains fatty acids that come from coconuts, it sometimes appears in products that use “greenwashing.” This term describes a company trying to portray itself or its products as more environmentally friendly than they really are.

The product label may have phrases such as “natural” or “eco-friendly” on it. However, it is worth remembering that CAPB still contains propylene glycol, which is a synthetic compound.

If a person would prefer to avoid CAPB, they can look for products that instead contain coco betaine, which is very mild on the skin.

Coco betaine is also a surfactant that comes from coconut. However, unlike CAPB, it is plant-based and combines fatty acids from coconut oil with betaine from beets.

Cocamidopropyl betaine is a combination of fatty acids from coconuts and propylene glycol. Manufacturers use it in various personal hygiene and household products. It acts as a surfactant, helping water bond with dirt and oil, making cleaning easier.

For many people, CAPB is a nonirritating ingredient. However, some individuals can be sensitive to it or the impurities that come from the manufacturing process. There is concern that CAPB may be harmful to aquatic life, too.

A nonsynthetic alternative called coco betaine has many of the same properties as CAPB.