Part of our guides to Skincare Ingredients Explained and Skincare Routines and Results.
Your skin hosts roughly a trillion microorganisms across more than a thousand bacterial species, and they do real work: crowding out harmful microbes, holding skin at its natural pH, supporting the barrier and regulating inflammation. Your cleanser affects that community more than any other product, because it's the one you apply most often and the one most capable of stripping it.
What is the skin microbiome?
A community of bacteria, fungi and other microbes living on the skin's surface. It's as individual as a fingerprint, and no two people carry the same composition.
It isn't passive. Beneficial bacteria produce acids that keep skin around its optimal pH, generate antimicrobial compounds that limit harmful species, support the lipids and proteins that make up the barrier, and help regulate inflammatory responses.
Which means a disrupted microbiome shows up as the things people usually blame on something else: skin that reacts to products it used to tolerate, redness that won't settle, breakouts despite a careful routine, and a barrier that feels tight however much moisturiser goes on it. Our piece on what your skin barrier does all day covers the overlap between the two.
What disrupts it?
Harsh cleansers, first and foremost. Sulfates and aggressive surfactants strip beneficial bacteria along with the dirt, and doing that twice a day prevents the community re establishing itself.
After that: over cleansing, antibacterial products that kill indiscriminately, pollution, UV, and the heat and air conditioning cycle that anyone living here knows well. Stress and diet play a part too, which is less intuitive but well documented.
Falling oestrogen belongs on the list as well. Barrier function and microbial balance both shift after 40, which is one reason skin starts behaving differently around then. Our guide to what changes after 40 goes through that.
Prebiotics, probiotics and postbiotics: what's the difference?
| What it is | How it behaves in a formula | |
|---|---|---|
| Prebiotics | Nutrients that feed the beneficial bacteria already on your skin | Stable, works with your existing microbiome |
| Probiotics | Live bacteria added to the product | Hard to keep alive and stable in skincare |
| Postbiotics | The beneficial compounds bacteria produce when they break prebiotics down | Stable, delivers the benefit without live bacteria |
Probiotics get the most attention and are the hardest to make work. Live bacteria are difficult to keep stable in a cream or a cleanser, and there's genuine debate about whether they colonise skin or simply pass over it.
Prebiotics and postbiotics sidestep that problem entirely. One feeds the bacteria you already have, the other delivers what those bacteria produce. Neither depends on keeping anything alive in a bottle, which is why they're the more reliable route.
Using both is better than either alone. Prebiotics build balance over time. Postbiotics deliver soothing and barrier support immediately. That combination is why we built PURIFY as the world's first pre and postbiotics blend for skin microbiome balance.
Why the cleanser matters more than the serum
Because it's the product most capable of undoing everything else.
A conventional cleanser is designed to remove oil and debris, and the surfactants that do that job efficiently don't distinguish between debris and the bacteria you want to keep. Every wash with a stripping formula clears ground the microbiome then has to recover. Twice a day, every day, it never quite does.
That's the loop behind a lot of adult sensitivity. Skin feels congested, so the response is to cleanse harder, which damages the barrier, which produces more oil and more reactivity, which prompts more cleansing. We've written about the cleanser mistakes that damage sensitive skin over 40 separately.
A cleanser worth using is sulfate free, pH balanced, rinses clean, and leaves the lipid layer intact. PURIFY pairs its pre and postbiotic blend with bearberry extract, and it's non foaming by design rather than by compromise.
How many times a day should you cleanse?
Evening is essential. Morning is a judgement call.
In the evening you're removing sunscreen, pollution and a day's accumulation, and leaving that on overnight works against the repair the skin does while you sleep. Our guide to what happens to skin overnight covers why that window matters.
In the morning, a humid climate makes a case for it, because most people here wake up oilier than they went to bed. But if your skin is dry or reactive, water alone is a legitimate answer. The formula matters more than the frequency either way.
Where it sits in the rest of the routine
Cleansing first, then MERACLE, then your serum, then SATURATE, then sunscreen in the morning.
Supporting the microbiome isn't a separate routine. It's the foundation the rest sits on, and a serum works considerably better on skin that isn't fighting its own cleanser. Our routine order guide covers the full sequence, and how much of a routine you actually need argues for keeping it short.
Questions we get asked
What is the difference between prebiotics, probiotics and postbiotics in skincare? Prebiotics feed the beneficial bacteria already on your skin. Probiotics are live bacteria added to a product, which is difficult to keep stable in skincare. Postbiotics are the compounds bacteria produce when they break prebiotics down, delivering the benefit without live bacteria.
Why does a cleanser matter more than a serum for the skin microbiome? A cleanser is the product most capable of stripping the microbiome and it is used twice a day. Sulfates and aggressive surfactants remove beneficial bacteria along with debris, leaving the barrier compromised.
Does a disrupted skin microbiome cause breakouts? It contributes. A balanced microbial community limits the bacteria associated with breakouts by competing with them for space and resources. Stripping it removes that competition.
Is microbiome skincare relevant in a humid climate? Yes. Heat, humidity, air conditioning and pollution all stress microbial balance, and the instinct to cleanse more aggressively when skin feels oily makes the problem worse.
Can I use prebiotics and postbiotics on sensitive skin? Yes. A good proportion of adult reactive skin traces back to a stripped barrier rather than to a specific allergy. PURIFY does contain naturally derived essential oils, so patch test first if those have caused you trouble before.
How long does it take to restore a disrupted skin microbiome? Comfort usually improves within a fortnight. Give any routine change 12 weeks before judging it properly.
Should I avoid antibacterial products entirely? For daily facial skincare, yes. They kill beneficial bacteria along with everything else. Hand hygiene is a different question.
Where to go from here
Look at what you wash your face with and find the surfactant. If the list opens with sodium lauryl sulfate or sodium laureth sulfate, that's the product working against everything else on your shelf.
Change that one thing first and give it a fortnight before you change anything else.