What type of substance is characterized by its ability to attract water?

The correct choice is humectant, which is specifically defined as a substance that has the ability to attract and retain moisture from the environment. In the context of skincare, humectants are often used in formulations to help hydrate the skin by drawing water from the air into the outer layer of the skin. Common examples include glycerin and hyaluronic acid.

Humectants play a vital role in maintaining skin moisture levels, which is particularly important in preventing dryness and ensuring skin health. Unlike emollients, which primarily work to smooth and soften the skin, humectants focus on increasing moisture content. This hydrating effect is essential in many cosmetic and dermatological products to promote a plump and well-moisturized appearance.

While emollients, emulsions, and solvents each have their own functions in cosmetic formulations, their roles differ significantly from that of humectants. Emollients provide barrier properties and soften the skin, emulsions are mixtures of oil and water used to blend different ingredients, and solvents are substances that dissolve other materials but do not inherently attract or retain moisture in the way humectants do.