Do I need sunscreen in the winter?

Yes. UVA rays pass through clouds and glass all year round, and it is UVA rays that are linked to pigmentation and premature aging.

Before or after applying makeup?

Apply it before any makeup, as the final step in your skincare routine, and allow a few minutes for it to absorb.

Sunscreen for dry and sensitive skin: how to choose

Sunscreen for dry or sensitive skin is not just a question of the SPF number. Dry skin loses water quickly and needs a texture that moisturises rather than dries, and sensitive skin reacts to fragrance and alcohol long before it reacts to the sun itself. That is why so many people find sunscreen irritating, when the problem is the formula rather than the protection.

This guide sets out what actually matters for these two skin types: texture, filters, quantity, and what to avoid. Every example is taken from products actually in stock, using the information on their pages.

The quick choice by skin type

Skin type	Suitable texture	What to look for
Dry	Moisturising cream	Glycerin, long hydration, fragrance-free
Sensitive	Milk or gentle cream	Fragrance-free, dermatologically tested
Dry, wanting an even tone	Tinted cream	A natural shade that adapts
Oily or combination	Mattifying gel-cream	Oil absorption, light feel

The numbers on the bottle and what they mean

The SPF number measures protection against UVB, which causes burning. UVA penetrates deeper and is linked to pigmentation and premature ageing, and it is UVA that passes through cloud and glass all year. So the SPF number alone is not enough: what also matters is whether the formula covers the broad spectrum.

Recent filters go further. The product pages name several: Mexoryl 400 from La Roche-Posay, aimed at ultra-long UVA between 380 and 400 nanometres; TriAsorB from Avène, covering UV and blue light up to 450 nanometres; and Tinosorb in the Daylong formula.

Quantity: the most common mistake

The figure on the bottle is measured in a laboratory using a generous layer. A thin layer does not give half the protection but a far smaller fraction. The practical rule for the face is roughly two finger-lengths, index and middle, about a teaspoon. Reapply every two hours under direct exposure, and after swimming or sweating, whatever the water-resistance claim.

Texture by skin type

Dry skin benefits from creams that combine protection with moisture. One available example: the La Roche-Posay hydrating cream SPF50+, whose page cites glycerin, thermal water and hydration lasting up to 8 hours, in a fragrance-free formula that does not sting the eyes.

See the product page: hydrating sunscreen for dry skin

Very sensitive skin, or skin prone to sun intolerance, does better with a milk texture. The Daylong Extrême page states it is aimed at fair, sensitive and very sensitive skin, with Tinosorb filters and no white cast.

See the product page: high-protection sun milk

For a lighter texture without losing moisture, there are serum-like formulas. The SKIN1004 page describes an ultra-light sunscreen that absorbs quickly with a dewy finish and no white cast, listed for sensitive, normal and dry skin.

See the product page: light fast-absorbing sunscreen

Tinted sunscreen: when it helps

Tinted sunscreen evens the complexion and replaces a thin layer of foundation, which helps when pigmentation is the concern. The Avène tinted SPF50+ page states it is aimed at dry and sensitive skin, with a velvety texture, hydration up to 8 hours and a natural shade that adapts to most skin tones.

See the product page: tinted evening sunscreen

What to avoid on sensitive skin

Added fragrance: a common cause of irritation, and formulas for sensitive skin usually state they are free of it.

Too little product: irritation is sometimes a mild burn rather than the formula.

Layering with exfoliants at the same time: acids increase the skin’s sensitivity to the sun.

Relying on sunscreen alone: shade, a hat and clothing remain the first protection during peak hours.

When to see a doctor

If a rash or itching appears after every exposure despite a suitable sunscreen, if there is known photosensitivity, or while taking medication that increases sun sensitivity, that is a matter for a dermatologist rather than for switching products. The same applies to any skin spot that changes in shape, colour or size.

Is SPF 30 enough, or is 50 needed?

The gap between 30 and 50 is smaller than the numbers suggest: both stop a high share of UVB, and the difference is a few percentage points rather than double. But that calculation assumes the full quantity, and most people apply far less. The higher figure therefore gives a practical safety margin when the layer is thinner than it should be, which is why ranges aimed at sensitive skin concentrate on 50 and 50+.

More important than the number is whether the product is comfortable enough to use every day. A heavy or sticky sunscreen gets abandoned within a week, while a lighter one at the same rating lasts months, and the difference in cumulative protection between them is large.

Water resistance and what it actually means

The phrase "water resistant" does not mean the product survives swimming. It means it keeps part of its protection after a defined time in water, after which it must be reapplied. And towel drying removes the layer faster than the water does, so reapply after drying even if the swim was short. Several pages here mention resistance to water, sweat and sand, which is useful in an Algerian summer but does not remove the need to reapply.

Timing: before going out, not as you go out

The Daylong page advises applying 20 minutes before exposure. The formula needs time to form an even layer on the skin, and stepping out straight after application leaves a window where protection is below the stated figure. For daily use, sunscreen goes on as the last skincare step and before makeup, with a few minutes before any layer on top.

One last point is about consistency rather than product: an average sunscreen used every day protects more than an excellent one kept for holidays. The rays that cause pigmentation and ageing reach the skin on the way to work and through a car window, not only at the beach.