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What is the right order to apply skincare ingredients like retinol, vitamin C, hyaluronic acid, etc.? — @bettyrosegold
Getting a shiny new skincare product is a super exciting moment, but the hard part comes later when figuring out where the heck to place it in your skincare routine. There's a lot of information swirling out there on what order to apply skincare products—FYI, the general rule is thinnest to thickest—but less often discussed are the ingredients inside the formulas.
Unless your routine consists of just cleanser and moisturizer (in which case, it's likely time for an upgrade), you're probably using an assortment of skincare ingredients. Unfortunately, we're not born with an innate knowledge of what order to apply said ingredients, and that really sucks because what you use—and how you use it—genuinely matters. Layering ingredients incorrectly could render them totally ineffective—or worse, irritate your face so you're discouraged from practicing skincare at all.
One way to think about ingredients is to look at their pH balance. Your skin's natural pH sits around 4.5 to 5.5, and the order of your products should go from lowest to highest. In other words, acidic products (pH 3.0 to 4.0) should always be applied before more neutral ones (pH 5.0 to 7.0). For example, vitamin C (which works at a more acidic, lower pH) should be applied before hyaluronic acid (formulated over 5).
But skincare is confusing enough without bringing math into the mix (let alone whipping out litmus papers and measuring the pH of all your products), so let's take a less scientific approach. I'll try to simplify it as much as possible by tackling one major ingredient at a time.
Vitamin C (the most common form being L-ascorbic acid) is one of the most potent and plentiful antioxidants in human skin. When applied topically, it brightens your complexion and helps neutralize the damage from free radicals. Although there's no law against applying vitamin C in the evening, most prefer to apply it during the day since its antioxidant properties act as a shield to deflect pollution and other environmental aggressors.
Retinol is a vitamin A derivative and the anti-aging industry's gold standard ingredient. However, not only does retinol make your skin more sensitive to UV rays, sunlight decreases the efficacy of the product, meaning you should definitely restrict your retinol use to nighttime. Because retinol can also potentially be irritating, Hadley King, MD, a board-certified dermatologist in New York City, recommends applying moisturizer (like hyaluronic acid—more on that in a sec) first to create a hydrating barrier.
AHAs and BHAs
AHAs (alpha hydroxy acids) are derived from sugars, and their primary job is to help with skin peeling. The most common AHAs in skincare products are glycolic acid and lactic acid, but there's also citric acid, malic acid, tartaric acid, and mandelic acid. On the other hand, BHAs (beta hydroxy acids) are oil-soluble. The most common one is salicylic acid, a willow bark compound used against acne.
While AHAs and BHAs are super effective, that potency comes with a high potential for skin irritation and increased skin sensitivity. That's why you definitely shouldn't use skincare acids at the same time as retinol, which can also increase sensitivity, warns Dr. King. And while it's not an acid, Dr. King adds that you also shouldn't combine retinoids with benzoyl peroxide; it will deactivate the retinoid and make it less effective.
Niacinamide might not get quite as much buzz as ingredients like retinol and vitamin C, but the skincare superstar is an unsung hero that deserves equal praise. Simply put, it's a form of vitamin B that's involved in many important cellular functions of the skin, the main one being its anti-inflammatory powers. Derms agree that niacinamide is a great addition to retinol and hydroxy acids because its soothing benefits can combat irritation. Combining these also increases the efficacy of the niacinamide, since the AHAs exfoliate the dead skin cells that could otherwise make it harder for the niacinamide to effectively penetrate.
However, niacinamide can decrease the efficacy of vitamin C several fold, so Dr. King recommends reserving niacinamide for evening use.
Like niacinamide, hyaluronic acid is a water-based ingredient used to bind moisture to the skin and pump up moisture levels. It's also probably the easiest ingredient to incorporate into your skincare routine, given that it pairs well with literally any ingredient. Hydration is a good thing to have any time, so feel free to apply day and/or night.
SPF (aka sunscreen) is relatively straightforward. As for when to apply, I would imagine that's a no-brainer—the morning, because sun, duh—but as for which order to apply, the answer is usually last. "Because zinc oxide and/or titanium dioxide (main ingredients in sunscreen) sit on top of the skin to scatter and deflect UV rays, physically blocking them from penetrating the skin, it makes sense to apply these products last," says Dr. King.
The exception is chemical sunscreens, which are made up of chemicals that absorb the UV rays, change the UV rays into heat, and release it from the skin. "To maximize their absorption, they should be applied before any occlusives (read: moisturizers)," says Dr. King.
Now let's bring all this information together. Taking our newly acquired knowledge about each ingredient into account, this is the best order for applying skincare ingredients.
Retinol OR AHAs/BHAs
The reason I recommend applying retinol in between hyaluronic acid and niacinamide is because layering your retinol between moisturizing ingredients (also referred to as the sandwich technique) can help your skin avoid any irritating side effects.
That being said, you don't have to use both niacinamide and HA, since they're both water-based treatments. Nor do you have to buy products from only one brand and apply one raw ingredient at a time. In fact, lots of skincare products now come out as hybrid products that already combine these active ingredients in one formula.
"I prefer a more streamlined approach rather than a routine with many steps," says Dr. King. "The key idea is that, in a Marie Kondo sort of way, you are identifying the skincare products that are best for you and cutting out the nonessentials."
In other words, everyone's regimen will look a little different, but the basic idea is that you're getting the benefits of all of these ingredients. And because you just learned virtually everything (ish) about skincare ingredients, you may now bask in the glory of your knowledge and layer your products like a true pro.