Skin Microbiome: all you need to know to choose better cosmetics
You've heard of the gut microbiome. But do you know that your skin has its own cosmetic skin microbiome — an invisible ecosystem that plays a crucial role in your skin health? Made up of billions of microorganisms, it's your skin's first line of defense against external aggressions. And yet, most conventional cosmetics disrupt it without you even realizing it.
This Earth Day week (April 22, 2026), it's more relevant than ever to question what we put on our skin. Because protecting your skin's microbiome also means taking care of your health — and making a concrete gesture for the planet by choosing natural, short, and sustainable formulas.
In this complete guide, you'll discover exactly what the skin microbiome is, why synthetic ingredients disrupt it, and how a simple routine with natural cosmetics can change everything. Scientific data, practical advice, and a comprehensive FAQ await you.
What is the skin microbiome?
The skin microbiome refers to all the microorganisms — bacteria, fungi, viruses, and yeasts — that live on the surface and in the superficial layers of your skin. It is estimated that about 1.8 million bacteria colonize each square centimeter of skin. That's more microorganisms on your body than human cells in your organism.
These microorganisms are not your enemies. Quite the contrary, they form a complex network that:
- Protects your skin from external pathogens
- Regulates skin pH (ideally between 4.5 and 5.5)
- Contributes to the skin's natural hydration
- Supports the local skin immune system
- Reduces inflammation and sensitivity reactions
According to a study published in the Journal of Investigative Dermatology (2023), skin microbial diversity is directly correlated with the health of the epidermal barrier. The more diverse your microbiome, the more resistant your skin is to external aggressions.
| Microorganism | Primary Role |
|---|---|
| Staphylococcus epidermidis | Anti-inflammatory protection, barrier against pathogens |
| Cutibacterium acnes | Sebaceous gland regulation (in balanced quantities) |
| Malassezia | Scalp balance, fungal protection |
| Lactobacillus | Protective acidification, maintains skin pH |
The microbiome is not the same for everyone. It varies according to your genetics, diet, environment — and especially, according to the cosmetics you choose to apply every day.
How conventional cosmetics disrupt your microbiome
The majority of classic beauty products contain ingredients that act as disruptors of the skin microbiome. These molecules are designed to extend the product's shelf life or improve its texture — not to respect your skin's ecosystem.
Biocidal preservatives
Parabens, MIT (methylisothiazolinone), and phenoxyethanol have broad-spectrum antibacterial properties. Designed to preserve formulas, they also eliminate beneficial bacteria from your skin. A study published in the European Journal of Dermatology (2022) showed that regular use of products containing MIT reduced skin microbial diversity by 40% over 8 weeks of daily use.
Harsh surfactants
SLS (sodium lauryl sulfate), present in most conventional shower gels and shampoos, destroys the skin's natural hydrolipidic film. This film is the primary habitat of the skin microbiome. Without it, beneficial microorganisms struggle to survive and pathogens take over.
Synthetic fragrances
Synthetic fragrances — often listed under the generic term "parfum" or "fragrance" on INCI labels — can group up to 100 different molecules, several of which have a documented negative impact on skin microbial balance.
Broad-spectrum antibacterials
Certain antibacterial agents present in soaps or hygiene products eliminate bacteria indiscriminately — both good and bad. The result: an impoverished microbiome, weakened skin, more reactive.
If you want to delve deeper into clean beauty and its criteria, our complete guide explains how to read INCI labels.
Signs that your microbiome is unbalanced
How do you know if your cosmetics are disrupting your microbiome? Your body sends specific signals. Here are the most common:
- Persistent tightness and dryness despite regular hydration
- Unexplained redness and sensations of heat after application
- Recurrent blemishes that systematically return to the same spot
- Unusual dandruff or itchy scalp
- Increasing hypersensitivity to products you tolerated well before
These symptoms indicate skin dysbiosis — an imbalance of the microbiome, where opportunistic bacteria take over beneficial bacteria. According to INSERM, approximately 40% of skins described as "sensitive" in Europe show signs of dysbiosis linked to cosmetic habits.
The good news: the microbiome is resilient. With the right products, it can rebalance in a few weeks.
How natural cosmetics protect your microbiome
Cosmetics formulated with natural ingredients offer several major advantages for the skin microbiome.
Short formulas = fewer risks
The fewer ingredients there are, the less chance there is of including disruptors. A formula with 8-12 well-chosen ingredients causes much less damage than a formula with 35 components, several of which are synthetic. This is the principle of skinimalism — the minimalist beauty trend gaining ground in 2026.
Selective preservatives
Naturally derived preservatives (like vitamin E or plant extracts with antimicrobial properties) have a selective bacteriostatic action. They slow the growth of pathogens without destroying the entire beneficial microbiome.
Vegetable oils: microbiome allies
Vegetable oils contain essential fatty acids (omega-6, omega-9) that nourish the skin's lipid film and create a favorable environment for beneficial bacteria. Argan oil, for example, is rich in oleic acid, which supports protective skin flora.
Aluminum-free = preserved underarm microbiome
Classic antiperspirants contain aluminum salts that block pores to stop sweating. This mechanism profoundly disrupts the underarm microbiome, which plays a key role in regulating natural odors. A natural Swiss deodorant without aluminum allows this microbiome to function normally.
The microbiome-friendly routine according to basic.
At basic., we made a clear choice from the start: short formulas, no unnecessary ingredients, handmade in Lausanne. No parabens, no SLS, no synthetic fragrances. PETA certified vegan.
Our philosophy: what we don't put in our products is as important as what we do.
The rechargeable classic — the deodorant that respects your microbiome
Our rechargeable classic deodorant is formulated with 12 carefully selected natural ingredients. It durably neutralizes odors thanks to sodium bicarbonate, precisely dosed to be effective without harming your underarm microbiome.
What sets it apart:
- Zero aluminum — no pore obstruction, no underarm microbiome disruption
- Zero synthetic fragrance — no microbial disruptor hidden behind a simple "fragrance"
- 12 natural ingredients — a short, readable, transparent INCI list
- Aluminum refill format — the same casing for years, zero plastic waste
At 10 CHF for 41g of product, it's the eco-responsible gesture that doesn't compromise on effectiveness. Each refill purchased = one plastic packaging avoided. This is also the spirit of rechargeable cosmetics that we have championed from the beginning.
Our advice for the transition: the first few weeks of using a natural deodorant may be accompanied by an adaptation phase — your underarm microbiome rebalances. This is a normal process that generally lasts 2 to 4 weeks. After this period, most users notice a natural reduction in odors, without resorting to chemical agents.
Skin microbiome and the planet: the invisible link for Earth Day
There is a striking parallel between your skin's microbiome and the planet's microbiome. Both systems operate on the same fundamental principle: microbial diversity guarantees resilience and health.
This Earth Day week (April 22, 2026), this link takes on a special dimension.
When you apply cosmetics loaded with biocides, these molecules end up in rinse water. They partially pass through wastewater treatment plants and disrupt aquatic ecosystems. Several studies have shown the presence of cosmetic preservatives in rivers and their impact on aquatic fauna — particularly their action on the endocrine system of fish.
Choosing natural cosmetics with short formulas therefore simultaneously protects:
- Your skin's microbiome — for lasting skin health
- The microbiome of soils and waters — for living ecosystems
- Your wallet — short formulas without superfluous ingredients cost less to produce
Good eco-microbiome practices for this Earth Day:
- Read INCI labels — if you don't recognize more than 3 ingredients, it's a sign
- Prefer refillable packaging to reduce plastic waste
- Choose brands that manufacture locally (less transport, more control)
- Avoid cosmetic overpackaging — a box in a box in a box is not a necessity
FAQ — Skin microbiome and natural cosmetics
What exactly is the skin microbiome?
The skin microbiome is the collection of microorganisms (bacteria, fungi, yeasts) that naturally live on the surface of your skin. It plays an essential role in skin protection, pH regulation, and local immunity support. It is estimated that there are 1.8 million bacteria per square centimeter of skin.
Does classic deodorant disrupt the underarm microbiome?
Yes, especially antiperspirants based on aluminum salts. These molecules block sweat glands and profoundly alter the underarm microbiome, promoting certain types of odor-producing bacteria. Natural aluminum-free deodorants better respect this microbial ecosystem.
How do I know if my cosmetics are harming my microbiome?
The most frequent signs are: persistent dryness despite hydration, unexplained redness, increasing hypersensitivity to products, and recurrent blemishes. If these symptoms appear after introducing a new product, it's a sign of skin dysbiosis.
How long does it take to rebalance the skin microbiome?
The skin microbiome can regenerate in 2 to 6 weeks depending on the initial state, after stopping disruptive products and adopting a gentler routine. For the underarm microbiome (after stopping a chemical antiperspirant), the transition generally takes 2 to 4 weeks.
Is a natural deodorant truly effective?
Yes, provided it has an appropriate formulation. Sodium bicarbonate neutralizes odors by changing the pH of the environment — odor-causing bacteria proliferate in an alkaline environment. Precisely dosed and combined with other natural active ingredients, it offers effective 24-hour protection without blocking natural perspiration.
Are natural cosmetics always better for the microbiome?
Generally yes, but not systematically. A poorly formulated "natural" cosmetic may contain irritating essential oils or allergenic plant extracts. What matters is the overall formulation: short, well-dosed, without broad-spectrum biocides. An INCI list of less than 15 recognizable ingredients is a good indicator.
What is skin dysbiosis?
Skin dysbiosis is an imbalance of the skin microbiome, where pathogenic microorganisms outnumber beneficial bacteria. It can be caused by aggressive cosmetics, an unbalanced diet, stress, or antibiotic therapy. It often manifests as reactive, dry, acne-prone, or sensitive skin.
Sources
- INSERM — Skin microbiota and skin diseases
- Journal of Investigative Dermatology — The Skin Microbiome (2023)
- ANSES — Risk assessment of cosmetic preservatives
- PubMed — Cosmetics and Skin Microbiome Diversity (2022)
- WHO — Data on chronic skin conditions
Ready to take care of your microbiome?
Your skin microbiome deserves a routine that is as simple as it is effective. At basic., we offer products formulated with only what's necessary — for your skin, and for the planet.
Discover the rechargeable classic — our natural aluminum-free deodorant, formulated in Lausanne with 12 natural ingredients. Rechargeable, PETA vegan, effective for 24h.