Somewhere in the past fifteen years, washing your face became a sequence of numbered stages. I want to look at how that happened and what the evidence for it actually is.
Where the format came from
The multi-step routine entered global awareness through Korean beauty culture, where layered application and a sequence of textures had been established practice.
It travelled through online communities, where the sequence became a format that could be shared, discussed and compared.
Which is a genuinely useful thing about it — it gave people a structure where previously there had been none.
And it created an obvious commercial opportunity, since a routine with ten steps requires ten products.
What the evidence actually supports
A small number of interventions have substantial evidence behind them.
Sun protection, used consistently, has the strongest evidence of anything in the category for both skin cancer prevention and visible ageing.
Retinoids have decades of clinical evidence for texture and fine lines, with the prescription strengths having more than the cosmetic ones.
Moisturising improves barrier function and the appearance of dry skin, which is straightforward.
Cleansing removes dirt and product, which is also straightforward.
Beyond that, the evidence base thins considerably and consists largely of manufacturer studies on small samples with short durations.
The order question
Layering order is generally given as thinnest to thickest, which has a physical logic — a heavy occlusive layer will impede anything applied over it.
Beyond that principle, most ordering advice is inference rather than evidence.
Some combinations genuinely interact — certain actives affect the stability or the skin tolerance of others — and those specific interactions are documented.
The general elaborate ordering schemes go well beyond what is established.
The barrier
The concept that has done most to change how people think about this, and reasonably so.
Skin has a barrier function, and disrupting it with harsh cleansing, over-exfoliation or too many actives produces irritation, sensitivity and worse appearance.
Which means more is not better, and a routine can actively cause the problems it is attempting to address.
The rise of barrier-focused messaging was a correction to several years of increasingly aggressive active use, and it was needed.
Purging
A concept worth being sceptical about.
The claim is that certain ingredients accelerate cell turnover, bringing existing blockages to the surface faster, producing a temporary worsening before improvement.
This is plausible for ingredients that genuinely accelerate turnover, and it is used to explain reactions to products that do no such thing.
The practical distinction is that purging occurs where you normally break out and resolves within a few weeks, while a reaction appears in new areas and does not.
Persisting through weeks of irritation because it might be purging has made a lot of skin worse.
The photography problem
Worth naming because it distorts the whole information environment.
Before and after images are affected by lighting, angle, camera, makeup, and increasingly by processing that is applied automatically.
Which makes visual evidence in this category close to worthless without controlled conditions, and controlled conditions are almost never used.
The improvements that are real tend to be gradual enough that nobody notices them week to week, which is exactly the opposite of what content requires.
What a reasonable routine looks like
Based on what has evidence rather than on what is interesting.
A gentle cleanser. A moisturiser suited to your skin. Sun protection every morning.
Then, if there is a specific concern, one active addressing it, introduced gradually and given several months.
That is four products and it covers most of what is demonstrable.
Adding more is not wrong and it should be understood as preference rather than as evidence-based improvement.
The obvious caveat
I am not medically qualified and this is a summary of how the category developed rather than clinical guidance.
Persistent acne, rosacea, eczema and pigmentation disorders are medical conditions with actual treatments, and a dermatologist will do more in one appointment than years of product experimentation.
Sunscreen and the testing question
Worth a specific section because it is the highest-value product in the category and the most confusing.
Protection factor testing measures a specific applied quantity, and that quantity is considerably more than most people actually use.
Which means the protection achieved in practice is lower than the number implies, sometimes substantially.
Applying more, and reapplying, matters more than the number on the bottle.
Regulatory frameworks differ between regions in which filters are approved, which is why formulations available in some markets are unavailable in others, and why the textures differ so much internationally.
The active introduction problem
How new products are added determines whether reactions can be interpreted.
Adding several at once means an adverse reaction cannot be attributed to any of them.
Introducing one at a time, with several weeks between, is slow and is the only approach that produces usable information.
Most people do the opposite, then conclude their skin is sensitive to everything, when the actual finding is that the experiment had no controls.