Which of the following is NOT a benefit of PREP skin care?

Moisturizing the skin is an important function of many skin care products, but selecting it as the answer indicates a misunderstanding of the specific benefits associated with PREP skin care. PREP products are designed to enhance the tanning experience and often focus on preparing the skin for subsequent tanning applications rather than providing deep hydration.

In the context of the other options: balancing pH levels is essential for optimal skin health and can aid in the effectiveness of tanning products; smoothing skin texture can also help with the even application of tanning solutions; and enhancing initial color development in a short period is a specific benefit aimed at accelerating results for users. Therefore, the emphasis of PREP skin care is more on preparing the skin for tanning rather than on deep hydration, which makes the choice concerning moisturization the one that does not align with the key benefits offered by PREP products.