Le pH de la peau : pourquoi le visage, le corps et le contour de l’œil ne se soignent pas pareil

We often hear that we should respect our skin’s pH, without always knowing what that means. And we imagine that the skin of the face, the body and the eye contour are completely different. The reality is more subtle, and understanding it helps to better choose one’s skincare, and above all to stop overdoing it.

What is the skin’s pH

At its surface, your skin is protected by a slightly acidic film, known as the hydrolipidic film or acid mantle. Its pH generally sits between 4.5 and 5.5, within a range from 4 to 6 depending on the person and the area. This acidity comes from sebum, sweat and the skin’s own flora.

This acidity is no detail. It plays three essential roles. It lets the enzymes that repair the barrier work properly. It maintains a healthy skin flora and keeps unwanted microbes at bay. And it ensures the skin’s proper renewal, by helping dead cells shed correctly.

When this pH rises — that is, when the skin becomes less acidic — this whole system is disrupted. The barrier weakens, the skin loses more water, it becomes more sensitive and more prone to redness.

The face: acidic, but quickly unbalanced

The skin of the face is acidic, like the rest. Measurements show a pH of around 4 to 5.5 on the forehead, a little more variable on the cheeks. Nothing extraordinary in itself.

What changes everything is its fragility in the face of what we apply to it. A classic soap is very alkaline, with a pH around 9 or 10. After washing with soap, the skin’s pH can stay disrupted for up to several hours.

This is why we advise against soap on the face, and more broadly any stripping cleanser. We cleanse gently, with a product that respects the skin’s pH, precisely so as not to break the acid mantle we are trying to preserve.

The body: more robust, but not uniform

The skin of the body is overall thicker and more resistant than that of the face. It tolerates richer textures and stronger cleansers. But its pH is not uniform everywhere. Fold areas — such as the underarms, the groin or under the breasts — are naturally more alkaline, as they are less aired and more humid. This is precisely why they are more prone to irritation.

The idea to remember is simple: a product designed for the body is formulated for thicker, more tolerant skin. It has no place on the face, which is finer and more reactive.

The eye contour: the most fragile area

This is where the difference is clearest, and it lies not so much in pH as in the skin’s structure. The skin of the eye contour is the thinnest of the body, about 0.2 millimetre. It has very few sebaceous glands, and therefore very little sebum to protect it, and almost no fatty tissue beneath.

As a result, this area retains water less well, its barrier is weaker, it dehydrates and shows marks more quickly, and it reacts more easily. It is also right next to the eye, which demands perfect tolerance. This is why an eye-contour treatment is not a marketing gimmick. This skin truly needs gentle, well-tolerated textures suited to its thinness. Applying a face cream that is too rich, or an active that is too strong, risks discomfort or even puffiness.

There is another, more technical reason. A formula that is too rich or too heavy, with large molecules, does not penetrate properly on such thin skin. Instead of being absorbed, it stagnates on the surface, congests and can clog the pores. This encourages the small white bumps known as milia, and as drainage is naturally weak around the eye, this accumulated weight can sustain puffiness and fluid retention. A good eye-contour treatment is designed precisely for this: light textures, suitable molecules that penetrate without overloading. It is not a pricier version of a face cream — it is a different formula.

What this changes for your skincare

A few simple principles follow from all this. We do not wash the face with soap or shower gel: we choose a gentle, pH-respecting cleanser to preserve the acid mantle.

And we favour a cleanser that rinses off with water. This is a point we often repeat. Milks, lotions, micellar waters and oils left on the skin without rinsing deposit a film and residues. A surfactant left in place increases water loss and can irritate over time, and a greasy film prevents the treatments applied afterwards from penetrating and being truly useful. The skin, meanwhile, has not been cleansed in depth, merely coated. Micellar water is handy on the go, but ideally it should be rinsed off. A cleansing oil is useful for removing make-up, provided it is then rinsed or followed by a cleanser that rinses off. The rule is simple: cleanse, then rinse — do not leave a film on the face.

We do not transpose a body product onto the face, or the reverse: the needs and the resilience are not the same. We reserve for the eye contour products designed for it, gentle and well tolerated, rather than spreading there what we use on the rest of the face. And in general, we avoid anything stripping: the best way to respect your skin’s pH is still not to assault it.

To know precisely what your skin needs, area by area, a Skin Diagnosis is the best starting point; the Cosmetic Coaching at Maison Andromède, in Génissac near Libourne, then helps you choose the right gentle cleansers and treatments suited to each area.

Key takeaway

Toute votre peau partage un même manteau acide, précieux pour sa barrière et sa défense. Les différences entre le visage, le corps et le contour de l’œil tiennent surtout à l’épaisseur de la peau, à la quantité de sébum et à la fragilité de chaque zone. C’est ce qui justifie des soins adaptés, et non un même produit partout. Respecter le pH de sa peau, ce n’est pas acheter plus, c’est choisir juste et ne pas la décaper.