The Neutrogena Hydro Boost Hydrating Serum is a popular choice for those looking to boost their skin's hydration levels. This serum is formulated with hyaluronic acid, a powerful ingredient that helps replenish and lock in moisture. It instantly hydrates the skin, leaving it feeling smooth and supple. The lightweight and oil-free formula make it suitable for all skin types, including oily and acne-prone skin. During the Amazon January sales, you can get this highly-rated hydrating serum at a discounted price, making it a great addition to your skincare routine.