Which ingredient is commonly used as a humectant to retain moisture in topical formulations?

Which ingredient is commonly used as a humectant to retain moisture in topical formulations?

• A. Isopropyl myristate
• B. Mineral oil
• C. Petrolatum
• D. Glycerin

Answer: (D)

Humectants attract and hold water to keep the skin hydrated in topical formulations. Glycerin is a classic humectant because its multiple hydroxyl groups make it highly hydrophilic, so it draws moisture from the environment and from deeper skin layers into the stratum corneum, improving hydration and reducing water loss. The other ingredients mainly act as emollients or barrier-forming occlusives: isopropyl myristate improves slip and feel but doesn’t attract water; mineral oil and petrolatum create a barrier that minimizes water loss without drawing moisture to the skin. So glycerin best fulfills the role of a humectant.

Humectants attract and hold water to keep the skin hydrated in topical formulations. Glycerin is a classic humectant because its multiple hydroxyl groups make it highly hydrophilic, so it draws moisture from the environment and from deeper skin layers into the stratum corneum, improving hydration and reducing water loss. The other ingredients mainly act as emollients or barrier-forming occlusives: isopropyl myristate improves slip and feel but doesn’t attract water; mineral oil and petrolatum create a barrier that minimizes water loss without drawing moisture to the skin. So glycerin best fulfills the role of a humectant.