Right now, your skin is home to approximately 1.8 trillion bacteria, fungi, and viruses. Before you reach for the nearest antibacterial cleanser — pause. The vast majority of these microorganisms are not your enemies. In fact, they're actively working to protect you. And your harsh face wash might be wiping them out.
Here's what's really living on your skin, why it matters, and what to do about it.
Your Skin Is an Ecosystem
Think of your skin like a rainforest. Every species in a rainforest plays a role — remove enough of them and the whole system starts to collapse. Your skin microbiome works the same way. It's a complex, deeply interdependent ecosystem, and it's easier to disrupt than most people realise.
The good news is that your skin has a star resident keeping things in order.
Meet Staphylococcus epidermidis
The most important beneficial bacterium living on your skin is called Staphylococcus epidermidis. It might not be a household name, but it's doing a remarkable amount of work on your behalf:
- It produces antimicrobial peptides that actively seek out and destroy harmful pathogens
- It trains your immune system, helping it learn what to attack and what to leave alone
- It keeps your skin barrier acidic, making the surface hostile to invaders
In short, it's one of the key reasons healthy skin can defend itself. When it thrives, your skin thrives.
The Problem with Most Cleansers
Here's where things go wrong. When you use a harsh cleanser, you're not just washing away dirt and excess oil — you're stripping away the entire microbial community your skin depends on, along with the chemical signals those bacteria use to communicate with your skin cells.
The main culprit is an ingredient called Sodium Lauryl Sulfate (SLS). It's found in the majority of foaming cleansers and it's extremely effective at cutting through oil — so effective, in fact, that it also strips away your skin's acid mantle and wrecks bacterial diversity in the process.
That "squeaky clean" feeling after washing your face? That's not a sign your skin is clean. It's a sign your skin has been structurally compromised.
What Happens When Your Microbiome Is Disrupted
When the balance of your skin's microbial ecosystem is thrown off, the effects go well beyond the surface. A disrupted microbiome leads to a compromised skin barrier, which in turn causes:
- Transepidermal water loss (TEWL) — moisture escaping from deep within the skin
- Chronic dehydration — skin that no product seems to fix
- Persistent inflammation — redness, irritation, and sensitivity that won't settle
- Heightened skin reactivity — skin that suddenly reacts to products it previously tolerated
Many people spend years cycling through products trying to solve these issues, not realising the root cause is the cleanser they've been using every single day.
How to Choose a Cleanser That Doesn't Strip Your Skin
The fix isn't complicated, but it does require knowing what to look for.
Check the pH. Your skin's natural surface sits at a pH of around 4.5 to 5.5 — slightly acidic. A good cleanser should match this range. Anything more alkaline disrupts the acid mantle and creates an environment where harmful bacteria can take hold.
Avoid SLS. Look for "0% SLS" or "sulphate-free" on the label. A cleanser can clean effectively without needing a harsh surfactant — it just needs to be formulated with that intention.
Give it time. If your microbiome has been significantly disrupted, don't expect overnight results. Research suggests it takes around 4 to 6 weeks of consistent gentle care for the skin's microbial balance to meaningfully recover. Patience is part of the process.
The Bottom Line
The future of skincare isn't about stripping skin back to a blank slate and rebuilding from scratch. It's about working with the biology that's already there. A microbiome-first approach — starting with a gentle, pH-balanced, SLS-free cleanser — is one of the most impactful shifts you can make in your routine.
Your skin already knows how to protect itself. The goal is to stop getting in the way.
This is part of an ongoing series breaking down the science of skin. Follow us on our social media and signup to our newsletters for more on what your skin needs at each phase of its daily cycle.
