What Is Carbomer?
Carbomer is the commonly used name for an ingredient called polyacrylic acid (PAA). Carbomer is a group of synthetic high molecular weight polymers of acrylic acid used in cosmetics and skincare products as thickening agents. They are primarily added to gel-like formulations, such as facial moisturizers, sunscreens, shampoos, anti-aging formulations, cleansers, and scrubs, to help control the thickness, flow, and consistency of the product.
The carbomer polymers have been used in cosmetics for over 50 years. Carbomers are large molecules prepared from relatively small monomers of acrylic acid and polyalkenyl polyethers. All of the Carbomer polymers are chemically similar, differing from each other in molecular weight and viscosity. Dry Carbomer polymers come in the form of white, fluffy powders.
Carbomer polymers can be found in a wide variety of product types including skin, hair, nail, and makeup products at concentrations up to 50%. You may notice a number associated with the carbomer name on the ingredient, this is the carbomer code. Carbomer codes (i.e. 910, 934, 940, 941, and 934P) are an indication of molecular weight and the specific components of the polymer.
The Carbomer polymers can have varying pH levels that must be neutralized in order for them to function as thickening agents. Formulations that contain carbomer polymers will sometimes have these neutralizing agents listed. Examples include Triethanolamine (TEA), sodium hydroxide, potassium hydroxide, and tetrasodium EDTA, just to name a few. Other times, companies will purchase pre-neutralized carbomers, which may or may not list the neutralizing agent.
the good:Carbomers help to improve the texture and sensory feel of formulations.
the not so good:Doesn’t impart any benefit to the skin as it is a texture enhancer.
Who is it for?All skin types except those that have an identified allergy to it.
Synergetic ingredients:Works well with most ingredients
Keep an eye on:Keep an eye out for all the different carbomers in your products.
Why Is Carbomer Used?
To understand the functions of carbomers, it is important to first understand how they work. When a carbomer is placed in a water solution at neutral pH, many of the side chains will lose their protons and acquire a negative charge. Because of this reaction, carbomers are able to absorb and retain water, and swell to many times their original volume. This is why carbomers are considered to be texture enhancers and are used to add thickness to products, particularly gel-like formulations.
Additionally, carbomers have the ability to distribute or suspend an insoluble solid in a liquid. Thus, carbomers are used to keep emulsions from separating into their oil and liquid components, as well as to control the consistency of cosmetics and other skincare products. By adding carbomers to things like shampoos, conditioners, creams, and lotions, formulations will appear more rich, smooth, and creamy.
Varying the amount of carbomer used in a product allows the formulator to create anything from a stiff hair gel that will stay exactly where you put it, a lotion with body but which still flows easily, or a rich cream that holds its shape. High amounts of carbomers in a gel may result in the product rolling or balling up of cosmetic products on skin, but this phenomenon depends on other formulary steps taken to minimize this effect.
Benefits to the skin
Interestingly, carbomer doesn’t seem to have any effect on the skin at all. Once a carbomer is applied to the skin and dries, you shouldn’t even notice it. Carbomers will not make the skin tacky, dry, or tight. The carbomer polymers aren’t in the product to promote any benefits, just to improve the texture of the product.
In addition to use in personal care products, carbomer polymers have a wide variety of commercial and industrial uses. Some examples include use as a fragrance carrier, medical bandages, wound dressings, and fire-retardant gel, just to name a few.
Is Carbomer Safe?
The safety of carbomers has been assessed by the Cosmetic Ingredient Review Expert Panel, a group responsible for evaluating the safety of skincare and cosmetics. Carbomer polymers demonstrated a low potential for phototoxicity, photo-contact allergenicity, skin irritation and sensitization at concentrations up to 100%. Upon evaluation of the scientific data, the CIR Expert Panel concluded that carbomer polymers were safe as ingredients in cosmetics and personal care products.
References:Cosmetic Ingredient Review, 1990. ‘Final Report on the Safety Assessment of Carbomers-934, -910, -934P, -940, -941, and -962’, International Journal of Toxicology.