Namely
Carbomers are hydrophilic synthetic polymers of acrylic acid. In cosmetics, they are used to thicken the preparations as a gelling agent or emulsifier, but also as a solvent to help the formulas stay well mixed. These are big molecules that do not penetrate the barriers of the skin. They improve the textures of creams or shampoos, so that they are more pleasant to use.
The CIR (Cosmetic Ingredient Review) believes that carbomers are safe for health in cosmetics. Indeed, they have been the subject of many tests and do not pose in general no problems.