All about cleansing - WIMJ cleansing guide
Daily cleansing is part of any proper skincare routine. Because it is such a basic step, we often take it for granted and often forget the "why" behind it.
So why do we need to cleanse the skin?
The first reason is to prevent infections. This includes skin and general body infections. (We wash hands to prevent microbes from getting into our mouth, for example). Cleansing removes or deactivates bacteria, viruses and fungi. As you can imagine, there is way more risk of getting bad bacteria on our hands than on our face. If we don't touch our face, cleansing the face skin for this hygienic reason a few times per week would be enough.
Here is where another reason for skin cleansing comes in. Natural and industrial air pollution means that pollutant particles gather on the skin surface. Residue of makeup and sunscreens also count as pollutants. (Even though they are way less harmful than air pollutants). All these particles can cause free radical damage, clog pores and even penetrate the skin barrier. This can lead to skin irritation and inflammation. This is why, especially in an urban environment, it makes sense to cleanse the skin more often than you would do for anti-microbial reasons only. Our face gets most exposed to air pollutants during the day, so it makes sense to cleanse it at night time. Clothes serve as a barrier to the pollutant particles. Anti-pollution cleansing is less important for the covered body parts than for the face. (Of course, we need to remove sunscreen and makeup residue from all areas we applied it to).
This is it. There are no other reasons to cleanse the skin. Skin own lipids (for example, sebum) is not a pollutant and does not need removal. The same goes for residue of moisturizers without SPF. This is why a "morning cleanse", after you slept in a clean air environment of your home, does not make much sense.
How about sweat? Sweat by itself is not a pollutant, but it can create nice conditions for bacteria to grow. Water on its own can remove fresh sweat (it is water soluble). So a shower without a cleanser is enough to remove fresh sweat. With time though, sweat breeds bacteria, and this is when we are back to the antimicrobial need for cleansing. In practice, if the sweat is older than 15-30 minutes, it is a good idea to remove it with a cleanser. Our face doesn't sweat a lot unless it is very hot or we exercise. In general, anti-sweat cleansing is more relevant for our underarms, groin area, and feet than face.
How cleansing works
If the thing we want to cleanse off is water-soluble (and does not contain bad microbes) - like fresh sweat - water can do the job. Most "dirty" things are not water-soluble though, they are oils.
You remember from a school chemistry course that oil and water don't mix. Water molecules can't "pick up" oil molecules (and you need first to pick something up to remove it). This is why we use cleansers. They are sometimes called "detergents". (Yep, an expensive skin cleanser and your dish washing liquid are close relatives).
Detergents include a special type of molecules that can bind to water and oil at the same time. We call them "surfactants". Surfactants "pick up" lipids and grab to rinsing water at the same time. Once the water is rinsed, bye-bye, the lipids are gone as well! These lipids can include include:
sunscreen & makeup,
lipids that are part of microbes (that's how washing deactivates microorganisms),
sebum and other oils mixed with air pollution particles,
visible dirt.
But here is a problem. Surfactants do not distinguish between "good lipids" and "bad lipids" - they can remove them all. This includes own skin lipids that are vital to the skin health.
As well as removing "good lipids", surfactants cause swelling of the upper skin layer. This makes the skin barrier more "porous" and different particles, including potential irritants, can penetrate it easier. The higher the cleanser's pH, the more swelling happens. Traditional soaps (and especially the home-made, "natural" ones) have the highest pH and cause the most damage.
Some surfactants (including soaps) can also bind to skin proteins. This also damages the skin barrier and leads to skin dehydration.
Overall, all cleansers damage our skin barrier. (And remember that skin barrier is important not only for hydration, but also for preventing acne and fighting photo-damage). If a cleanser doesn't damage a skin barrier, it doesn't cleanse. This is why cleansing needs balance: we want to do it only when the harm from pollutants is greater than the harm from a cleanser. For example, this is the case at the end of the day, especially if we spent time outside in an urban area and had sunscreen or makeup on. Or when we touched a surface that could be contaminated with disease-causing bacteria. At the same time, the harm from cleanser outweighs the benefit of removing possible pollutants from the skin in the morning - if we washed our face the evening before and spent the night in a relatively clean environment.
As a rule of thumb, for most people, it's best to cleanse the face only once per day, at night. It is also best to do it in one step, because each cycle of applying detergent and rinsing harms the skin.
But how about no-rinse cleansers? In short, forget this idea. Without rinsing, surfactants from a cleanser (micellar water or a cleansing wipe for example) still remain on the skin and keep causing harm. No matter what the product instructions say, it's best to always rinse off a cleansing product with water. Of course, we don't always have access to water, so sometimes no-rinse cleansers are the only choice. Still, rinse them off as soon as you can.
Types of cleansers
Overall, there are two main categories:
Soaps: traditional soap bars, liquid soaps and "all-natural" hand-made soaps. These are the most skin-damaging type of cleansers (after your bathroom cleaner and dish-washing liquid). Avoid them if you can. Please don't get fooled by marketing and ingredient labels on soaps that mention nourishing oils. Oils in soaps undergo a chemical reaction that turns them into harsh surfactants. It doesn't matter how good the original oil was - in a soap, it turns into a little skin-barrier-eating monster.
Syndets: these are a very broad category of cleansers with different types of synthetic surfactants. They are kinder to our skin than soap, but there is a huge difference between different kinds of synthetic surfactants and the overall cleanser formulations.
Cleansers with high-foam "efficient" synthetic surfactants sodium lauryl sulfate, sodium laurate, sodium cocoyl isethionate. This group includes Dove bars and most modern hand and body washes. The good thing is that their pH is closer to the skin's own, so they cause less dehydration compared to soap. Still, in the synthetic detergents family, they are the harshest - precisely because they are very good (efficient) in removing lipids.
Cleansers with less efficient (gentle) synthetic surfactants (there are many different kinds including lauryl betaine, cocamidopropyl betaine, sodium lauriminodipropionate, sodium stearate). Most face cleansers (regardless of their texture - lotion, cleansing balm or oil) fall into this category. These cleansers are less efficient in removing lipids. It is a bad thing if you want to remove layers of grease, but a good thing if you are removing a bit of makeup and air pollutants from the day.
Modern synthetic detergents for skin use a lot of techniques for reducing the damage to the skin barrier.
First one is to mix different types of gentle surfactants in one cleansing product. This way they diversify the damage from each surfactant type. It makes it easier for the skin barrier to recover.
The other technique is adding skin-loving humectants and emollients to the cleanser. It can reduce the damage, but still, the effect is limited. The "good" ingredients simply do not stay long enough on the skin to have an effect (and you don't want your cleanser to remain on the skin longer than needed for cleansing). A cleanser, by definition, cannot be moisturizing or anti-aging. At best, it can be less drying.
Finally, the most promising "harm-reduction" technique in cleansing is a polymer surfactant system. Modified polymers act as "helpers" to surfactants and make them less "aggressive". As a result, the cleanser needs less surfactants to get the job done. This means less damage to the skin barrier. To spot a cleanser with the polymer technology, look for "Carbomer" on the ingredient list (it is not a 100% accurate method, but there is no better one to our knowledge).
Cleanser textures and formats
Synthetic cleansers come in many different textures or formats: lotions, oils, balms, waters etc. The texture itself tells little about how gentle the cleanser is. It is rather a matter of personal preference.
Here is an overview of the most popular cleansing textures.
Bar cleansers like the ones from Clinique, Drunk Elephant and alike. These are not soaps, but gentle detergents in a solid form. They can be as gentle as liquid cleansing formulations. There is a risk though that you'd end up using them in higher concentration compared to a cleansing lotion (which would mean more damage to the skin barrier).
Cleansing lotions and washes. These are liquid formulations. Their advantage compared to bars is that the concentration of surfactants is fixed by the formulator, and you won't end up with more surfactants on your skin than intended. As a rule of thumb, lotions tend to be milder than washes. This is because the washes often come with foaming. Surfactants can create foam, but it is not related to their cleansing action. The issue is that to create a good foam, formulators sometimes add more surfactants to a product than they'd do for cleansing performance only. As the result, foaming cleansers often are harsher on the skin.
Cleansing milks. They are actually a version of a cleansing lotion, but these products often are marketed as "no-rinse" ones. Still rinse them off.
Micellar waters. These are, in essence, diluted versions of cleansing lotions. With a cleansing lotion or wash, micelles (it's just a name for an arrangement of surfactant molecules in a solution) form once the water is added in the cleansing process. Micellar waters comes with pre-formed micelles. The advantage of it is that the concentration of surfactants in contact with the skin is lower. On the other side, you need to use a cotton pad to apply micellar water, and this comes with extra rubbing that can also damage the skin. In any case, you need to rinse off the micellar water at the end.
Cleansing balms and oils. Unlike the formats discussed above, these detergents are oil-based. It can make them milder on the skin, makes them better at removing makeup, but also introduces a risk of clogging pores.
Finally, there are also different "mechanic" helpers for cleansing like brushes and cleansing cloth. They can help remove dirt and pollutants more efficient, but they can also damage the skin physically in the process. Most honest dermatologists advice to stay away from cleansing brushes. Harsh-textured cloth and spongers are also not a good idea. Microfiber cloth is more gentle of the skin though, so it could be an OK option to increase the cleansing efficiency if you avoid rubbing.
What is the best approach to cleansing your skin?
Here is the summary:
As a rule, cleanse once per day, at night (of course, make exceptions if you sweat a lot or are in a very polluted environment).
Avoid soaps and "efficient" foaming cleansers if you can.
Cleanse in one step: it is way better for the skin barrier than double-cleansing. You might still need a "pre-cleanse" if you wear a water-proof makeup. Try to limit it to the area where it's needed (e.g. eye area for mascara and liner).
Avoid rubbing with your hands or cloth/sponges. It is better to use more product than adding physical impact of rubbing.
Always, always rinse off your cleanser with water, even if it's marketed as a no-rinse product like micellar water or cleansing wipe.
Don't fall for "deep cleansing" rituals. Your normal daily cleanser is enough to get the job done. The deeper the cleanse, the greater the damage.
Do not leave a cleanser longer on your skin than needed for cleansing.
Don't expect other skin benefits from a cleanser than cleansing. All the moisturizing, anti-aging, anti-pigment goodness comes from products that stay longer on your skin. Anti-acne medicated cleansers are an exception to the rule. These cleansers include salicylic acid or benzoyl peroxide and can have an anti-acne action. We do not recommend medicated cleansers as your daily option though because of the irritation risks.
Sources:
The science behind skin care: Cleansers