How to choose and apply face sunscreen

The best sunscreen isn't the most expensive or high-tech; it's the one you actually apply, in sufficient quantity, every day.

But you still need to know how to read a label. Mineral or chemical, SPF, PPD, circled UVA logo: behind this vocabulary lie concrete choices for your skin type. Let's sort it out, calmly.

The best sunscreen is the one you apply in sufficient quantity, every day.

Mineral or chemical: two ways to filter

Mineral filters—zinc oxide, titanium dioxide—primarily work by reflecting and scattering UV rays on the skin's surface, as highlighted by the reference synthesis on photoprotection. They are well-tolerated, suitable for reactive skin, but can leave a white cast. Chemical (organic) filters absorb UV energy and dissipate it; their textures are lighter and invisible, at the cost of sometimes lower tolerance. Neither family is "toxic" by nature: what matters is the spectrum covered and the regularity of application.

SPF, PPD, UVA: decoding the acronyms

SPF measures protection against UVB rays, which cause sunburn. But it's UVA rays that penetrate deeper and accelerate aging. This is where PPD, the UVA protection factor, comes in, and especially the "UVA" logo encircled: in Europe, it guarantees that UVA protection reaches at least one-third of the SPF, in accordance with the European Commission's 2006 recommendation. Specifically, always look for this circle: a high SPF without proportionate UVA protection allows the most aging radiation to pass through.

The right texture for your skin

The best SPF is useless if the texture discourages you from applying it. Oily or blemish-prone skin: opt for a matte finish, "non-comedogenic" claims, often fluid chemical filters. Dry skin: a richer, moisturizing emulsion. Sensitive or reactive skin: mineral filters, which are better tolerated and less likely to sting. Olive or dark skin: beware of the white cast of untinted minerals, and turn to tinted or chemical formulas. The right SPF is the one you'll want to reapply.

The actual amount, the detail that changes everything

This is the most common mistake. The displayed SPF is measured at 2 mg/cm², which is equivalent to about half a teaspoon for the face and neck. However, as documented by Petersen and Wulf, most people apply two to three times less. The result: an SPF 50 applied too sparingly often protects like an SPF 20 or less. Real protection therefore depends less on the number on the tube than on the dose applied. A generous SPF 30 is better than a thin layer of SPF 50.

Reapplying, the step we forget

Sunscreen is not a permanent shield. It degrades, washes off with sweat, water, friction, and the simple passage of time. When exposed, the rule is to reapply every two hours, and systematically after swimming or exercise. For daily urban use, a second application in the middle of the day significantly enhances protection. Without reapplication, even the best product loses most of its effectiveness over time.

The Paradermia approach

Our pharmacist does not designate a universal "best" sunscreen: she starts with your skin and your life. The right spectrum—high SPF and circled UVA logo—the texture you'll enjoy wearing, the sufficient dose, and reapplication. Three simple reflexes that are worth all the marketing superlatives. A well-chosen and well-used sunscreen is the most cost-effective anti-aging treatment there is.

Frequently asked questions

Should I prefer mineral or chemical sunscreen?
Both protect well if they are broad-spectrum. Mineral sunscreens are better for sensitive skin, while chemical sunscreens offer lighter textures. The best one is the one you actually apply every day.

How much sunscreen for the face?
About half a teaspoon (2 mg/cm²). Most people apply two to three times less, which greatly reduces real protection.

How often should I reapply?
Every two hours when exposed, and after every swim or sweat. In the city, a second application in the middle of the day is enough to maintain good protection.