One of the most common questions I get asked is whether it’s ok to layer certain skincare ingredients and, if so, what’s the best way to do it.
I have a lot of information on my Instagram page and website about this but since I get asked these questions so frequently, I thought I would compile everything into one downloadable guide!
How To Layer Your Skincare Products
As a general rule, layering your skincare products from thinnest to thickest is recommended. That means that the product with the thinnest consistency would go first (e.g. toner) and the product with the thickest consistency would go last (moisturizer).
For example:
In reality, as long as all your skincare products can penetrate your skin (i.e. you’re not trying to apply a water-based serum over an occlusive moisturizer), the order that you apply them doesn't matter too much.
The only exceptions being cleanser, which should go first so you don’t wash off all the products you’ve just applied (exception = short contact therapy), and sunscreen, which should be the last step in your AM routine.
While “thinnest-to-thickest” is the most recommended way to apply your products (and the easiest to remember) there are other layering techniques that you may wish to consider, like buffering, sandwiching, and short-contact therapy.
Buffering
Buffering generally refers to applying your moisturizer before an active ingredient in order to reduce the irritation potential of that active ingredient. It's often used to reduce irritation from acids and retinoids.
The idea is that it slows skin penetration. However, when your skin is well hydrated it may also be easier for active ingredients to penetrate (e.g. damp skin vs dry skin)
Sandwiching
Sandwiching is similar to buffering but you apply a moisturizer before and after your active ingredient. Again, it's usually used for actives that can cause skin irritation like acids and retinoids.
It can be a useful option if you have very dry and/or sensitive skin.
Short-Contact Therapy
Short contact therapy is where you apply an active ingredient, leave it on for a set amount of time (e.g. 5 mins) then rinse it off. It can be a wash-off mask, at-home peel, or a cleanser with an active that are designed to be washed off after a certain amount of time. However, you can apply the same principle to any irritating active ingredient - particularly if you're prone to skin irritation.
The Biggest Myths Surrounding Skincare Layering
You’ve probably heard many different ‘rules’ about which skincare ingredients you can and can’t combine. The most common myths include:
In reality, the only reason you may want to avoid combining skincare ingredients is if using the ingredients together is going to increase your risk of skin irritation.
Are Differing pH's An Issue?
First things first, your skin’s natural surface pH is slightly acidic with a pH level anywhere between 4.7 - 6.0. Any skincare product you apply to your skin has to adjust to this pH and is usually formulated with this in mind.
When you hear people talk about differing pH levels in skincare, it’s usually a misunderstanding about how skin care product formulation works. For example, a glycolic acid or vitamin C (as ascorbic acid) product will be more effective if the formula has a pH of 3.5 or less, NOT if your skin has a pH of 3.5 or less.
Any skincare ingredient that has a similar pH to your skin (e.g. niacinamide, retinol) won’t make acidic products, like glycolic acid and vitamin C, any less effective than your own skin would.
The issue of pH differences only becomes a problem when formulating products that contain niacinamide and glycolic acid together.
Can You Use Niacinamide With Acids?
Niacin may be as effective as niacinamide, but it activates your skin's immune system (Langerhan cells) which leads to the release of substances (prostaglandins) that increase inflammation and blood flow to your skin.
This facial reddening is often referred to as ‘niacin flush’ and can cause an uncomfortable or tingling sensation.
Many people avoid layering niacinamide and acids for this reason. However, niacinamide is a very stable ingredient and it takes a very low pH, a very high heat, and a long time to convert niacinamide to niacin in laboratory experiments.
So, again, this is more of an issue when it comes to multi-ingredient product formulation than with layering niacinamide and glycolic acid together. If you’re worried about niacin flush, be careful when using skincare products that contain niacinamide and glycolic acid in the same formula.
However, if you are layering niacinamide and acids together as two separate products, then it’s unlikely you need to worry.
Skincare Ingredients That May Increase The Risk of Irritation When Combined
Some skincare ingredients can cause irritation and skin sensitivity and should be layered with caution - especially if you have sensitive skin or a damaged skin barrier.
Examples of skincare ingredients that commonly cause irritation include:
Please note that this is not an exhaustive list and product formulation will play a huge role in how irritating a skincare ingredient is. As will the overall condition of your skin.
These ingredients should also be introduced one at a time into your skincare routine.
Skincare Ingredients That Will Rarely Cause An Issue When Combined
In contrast to the above, some skincare ingredients are very unlikely to cause skin irritation and can actually help prevent it. This is mainly the case for soothing and hydrating ingredients like:
It’s unlikely that you would experience any irritation even if you layered all of these ingredients one after the other (product formulation depending).
Layering Issues - Damp vs Dry Skin
Another concern about layering skincare ingredients surrounds how each ingredient should ideally be used. For example, irritating active ingredients, like retinol and glycolic acid, should ideally be applied to dry skin while humectants, like hyaluronic acid, are ideally applied to damp skin and followed with an moisturizer/occlusive.
So for example, if you were looking to layer hyaluronic acid and glycolic acid you might be concerned about how to layer them while following these ‘rules’.
The main reason that you are advised to use irritating ingredients, like glycolic acid, on dry skin rather than damp skin is because damp skin is more permeable – meaning that skincare ingredients find it easier to penetrate your skin's barrier.
That’s great for most skincare ingredients, isn’t it? After all, easier penetration means increased effectiveness, right?
Right! Except, increased effectiveness also means increased risk of irritation.
Humectants, like hyaluronic acid, aren't irritating and, because they draw water into your skin, the damper your skin the better!
It’s particularly important to apply humectants to damp skin if you live in a dry climate. This is because they can only draw water from your environment if there is plenty of moisture in the air (a humid climate).
If there isn’t much moisture on the surface of your skin or in your surrounding environment, humectants can only draw moisture from your dermis.
In most cases, this isn’t a problem – your dermis has plenty of moisture to spare. However, if all the moisture being pulled from your dermis isn’t locked in with a thicker moisturizer, it can escape from your epidermis and leave you with dehydrated skin.
So how can you get around the damp vs dry skin issue? (let’s use the example of hyaluronic acid and glycolic acid)
