Theres so much that your body does to reset and refresh while youre sleeping, and your skin is no exception.

Just like our entire body, the skin has a circadian rhythm, said dermatologist Dr. Helen M. Torok . It repairs at night and protects during the day. The skin works hard to renew itself from the damage done throughout the day. Your skin cells regenerate at night, recovering from high levels of cortisol, the stress hormone, that can wreak havoc on your body during the day.

As such, its important to make the most of the money youre spending on skin care during the overnight hours, when it can work its magic most effectively. Essentially, its your chance to undo everything that you did to your skin throughout the previous day.

The repair of damage from UV exposure, pollution and other environmental stressors occurs at night, when the skins blood flow increases, said dermatologist Dr. Sonia Badreshia . This is also when collagen production is boosted and harmful free radicals are neutralized. Dermatologist Dr. Blair Murphy-Rose added, Its believed that the rate of skin renewal doubles at night.

Your skin absorbs products better when youre sleeping.

As productive as the skin is at night, you can make it even more so with the application of products it can really drink in and use. If you arent doing targeted nighttime care, youre missing the opportunity to support skins natural repair mechanisms, Badreshia said.

Your nighttime skin care routine should facilitate repairs and regeneration, Murphy-Rose said. The nighttime skin care product you apply can boost the skins hydration overnight or target cell turnover while you rest, dermatologist Dr. Claire Wolinsky said.

Theres one thing you MUST do at night.

Each of the experts revealed what they believe to be the biggest non-negotiable for nighttime skin care.

Murphy-Rose insists on using an eye cream. Our skin undergoes significant water loss through the skin at night if we dont take measures to prevent it, Murphy-Rose said. While some will tell you that an eye cream is unnecessary, the truth is that an undereye cream, which is typically richer than your facial moisturizer, can help to prevent water loss through this very thin skin while sleeping. Dehydrated eyes are more tired-appearing eyes, so I do recommend applying an undereye cream before bedtime.