The term "skin cycling" has gone viral on social media but what is it and what are its benefits? The concept of skin cycling applies to a nighttime skincare routine, which involves using active ingredients only on certain days, and following them with ‘rest’ days.
A four-day cycle is the most popular and typically comprises using active ingredients for two nights of the week, followed by two nights of rest—and then repeating.
The idea is that adopting a skin cycling routine can help prevent the skin barrier from being compromised due to overuse of active ingredients—plus, it’s a great way to create a consistent and effective routine that helps the skin work optimally.
You’re probably wondering how this impacts your skincare routine. Let's break it down and understand the science behind this trend.
Fig. 1: The oscillation of human skin properties as they cycle through the day and night. For example, skin penetration has been shown to be higher at night than during day. Higher values for sebum production occur during the day. Adapted from, Harry’s Cosmeticology 9th Edition, Pernodet and Pelle.
What is your skin doing during the day?
During daylight hours, your skin is constantly exposed to aggressors like UV radiation, pollution, and free radicals, all of which can cause DNA damage. This means that during the day, your skin is protecting itself. You want to do everything you can to support its natural defenses.
Physiological changes that take place in your skin during the day:
- Lower Temperature: The surface temperature of your skin is lowest early in the day. Your skin gets a lot of heat exposure from the sun, though, which can increase inflammation, redness, and pigmentation.
- Increased Sebum Production: Your skin’s production of sebum (oil) peaks in the early afternoon. This is basically your skin creating a natural film to protect itself from the environment (and the reason you may sometimes feel your skin is an oil slick by the end of the day).
- Better Moisture Barrier Function: Studies suggest your skin is better at holding on to moisture during the day thanks to improved barrier function. This results in better hydration levels but also means your skin is less receptive to skincare products.
- Increased Antioxidant Production: Your skin’s natural antioxidant production is increased during the day as it tries to protect itself from DNA damage caused by free radical molecules.
What is your skin doing during the night?
If daytime is all about defense, nighttime is all about offense. This is when your skin gets to work repairing any damage that was incurred throughout the day. Even though your skin is constantly working to repair itself, these processes definitely peak in the evening. (They don’t call it “beauty sleep” for nothing.)
Physiological changes that take place in your skin at night:
- More Permeable Barrier: Now that your skin isn’t facing an onslaught of environmental aggressors, your skin’s protective barrier function is decreased. This means two things: 1) Your skin is more receptive to products, so you want to take advantage by adding a serum to your nighttime routine. 2) It’s super important to use a well-formulated moisturizer for your skin type to prevent water loss and support your skin’s moisture barrier.
- Higher Cell Proliferation: At night, your cells are growing and dividing at a higher rate so they can regenerate.
- DNA Repair & Higher Protein Production: Your skin gets to work repairing DNA damage from the day. This also helps bolster and strengthen your skin’s immune system.
Best time for your nighttime skincare routine
Skin cycling refers to the idea of using a different lineup of products for each night changing up the order of your actives in order to optimize their effectiveness. This matters because – PROTEINS!
The proteins that run your body like clockwork, telling you when to sleep, when to eat and when to wake up are all part of your circadian rhythm, or your internal clock. These proteins also dictate when your skin cells are most hungry, and that's between 2-4 am! However, unless you are a night owl, you wouldn't want to be primping your skin at 2 am. We now know that these processes actually kick in as soon as the sun starts to go down. Because your skin has its own circadian rhythm, the loss of daylight signals that it’s time to start moving into repair mode, even if you haven’t gone to bed yet. This may mean that it’s beneficial to do your nighttime skincare routine earlier in the evening rather than waiting until right before your head hits the pillow.
This is also the reason to not sleep in your makeup and have your skin cells feed on your makeup and grime when they are at their hungriest.
Key skincare ingredients for nighttime
With this in mind, here are the best skincare products to use at night. All of these ingredients boost your skin’s natural reparative processes.
During the day, your skin uses up its antioxidant supply to defend against free radicals. Applying antioxidants topically at night means your skin can use them for repair instead.
Retinol, or vitamin A, is technically also an antioxidant. It boosts skin cell turnover, which helps the skin to regenerate itself from within.
Exfoliating acids like AHAs and BHAs dissolve dead cells on the surface of your skin. These dead cells can make your skin look dull and may make it difficult for other active ingredients to penetrate effectively. Acids also help reduce unwanted pigment and encourage a more even-toned complexion.
Peptides help build and repair collagen that’s been damaged by environmental aggressors. Collagen loss is a key component of skin aging, so peptides are a great (and generally well-tolerated) ingredient to use for skin repair.
Benefits of skin cycling and using the right products
Your skin goes through a 28-day cycle where new cells are made and travel up to the surface. Dead cells keep shedding away, making way for these new cells. Skin cycling helps nourish these newer cells.
The iuno protocol has multiple steps through the 28 days that help your skin get the right nourishment it needs. The protocol starts with the right dose of actives that are calibrated for polishing off your dead cells followed by moisturizing your exposed skin layer. We then begin your repair protocol with anti-aging, followed by polishing, moisturizing and repair followed by anti-aging and finally end with brightening.
The set of ampoules for each function are grouped based on your biological skin cycle and its ingredients and dosage are individualized to help you meet your skin goals.