The DEEP SERUM by NOTO is a hydrating serum that aims to provide moisture to dry skin. Ashley, in her video review, mentioned that the serum has a pleasant citrusy smell and a lightweight texture. However, she did not notice a significant improvement in hydration after using the product. Ashley found the serum to be a nice addition to her skincare routine, giving her skin a dewy finish when layered with her Solowave. Despite this, she believes there are other products that offer better hydration benefits. Overall, the DEEP SERUM by NOTO may be suitable for those looking for a lightweight serum to add a subtle glow to their skin, but it may not be the best option for intense hydration. Stay tuned for Ashley's upcoming review on another product.