What ingredient is primarily responsible for making a cream dense?

The ingredient primarily responsible for making a cream dense is carbomers. Carbomers are a group of synthetic polymers that are widely used in cosmetic formulations due to their ability to thicken and stabilize products. When dispersed in a liquid, carbomers swell and form a gel-like matrix, which increases the viscosity of the cream. This helps to create a luxurious, dense texture that enhances the product's application properties and overall feel on the skin.

While other ingredients like glycerin, dimethicone, and petrolatum have valuable functions in formulations—such as moisturizing or providing occlusiveness—they do not primarily serve the purpose of thickening a cream in the same way that carbomers do. Glycerin is a humectant that attracts moisture, dimethicone acts as a silicone that adds smoothness and reduces greasiness, and petrolatum provides an occlusive barrier. Each of these has its own role but does not contribute to density in the formulation as effectively as carbomers.