Sunscreen: why it matters most and how to choose one

Short answer: use a broad-spectrum sunscreen of SPF 30 or higher every morning, apply about two finger-lengths to the face and neck, and reapply every two hours when you are outdoors.

What UV does to skin

UVB rays cause sunburn. UVA rays reach deeper and contribute to wrinkles, loss of firmness and dark spots. UVA passes through clouds and window glass, so a daily habit matters more than a few beach days.

How to choose

• Oily or acne-prone skin: a fluid or gel texture.
• Dry skin: a cream.
• Sensitive skin and children: a mineral sunscreen with zinc oxide or titanium dioxide.
• Dark spots: SPF 50 every day. Tinted formulas also filter part of visible light.

How to apply

• Last step of the morning routine, after moisturiser.
• About two finger-lengths for face and neck, including ears and the back of the neck.
• Reapply every two hours outdoors, and after swimming or sweating.
• Makeup with SPF is not enough on its own: use it on top of sunscreen.

Sun in Tunisia: a year-round habit

Tunisia sits on the Mediterranean between roughly 30 and 37 degrees north, with long hours of sunshine for most of the year. From late spring to early autumn the midday UV index is regularly very high (8 and above on the World Health Organization scale), and it stays moderate to high on clear days in winter. UV is not heat: a cool, windy day in April or a cloudy day in October can still burn, because the wind cools your skin without reducing UV.

Sand, water and light-coloured walls reflect part of the UV back onto the face, so the beach, the sea and a white terrace add to the dose you get from the sky. Heat also makes you sweat, and sweat, towels and swimming remove sunscreen faster than a normal office day.

Choosing a texture for heat and humidity

Coastal cities such as Tunis, Sousse and Sfax are humid in summer, and heavy creams can feel greasy and slide off. Fluids, gels and gel-creams usually feel lighter in that weather, and matte finishes help oily skin. For the beach, a water-resistant formula keeps its protection longer during swimming and sweating, but it still needs reapplying after towelling. In the dry heat of the south and in air-conditioned rooms, dry skin may prefer a cream.

How much is enough

SPF is measured with a thick layer of 2 mg per square centimetre. Most people apply half of that or less, which gives much less protection than the number on the tube. Two finger-lengths of product for the face and neck, or about a quarter of a teaspoon for the face alone, is close to the tested amount. SPF 30 filters about 97% of UVB and SPF 50 about 98%: applying enough, and reapplying, matters more than the step from 30 to 50.

Common mistakes

• Using sunscreen only on beach days, and not for the daily commute, the market or a drive (UVA passes through car side windows).
• Forgetting the ears, the neck, the hairline and the back of the hands.
• Applying once at 8 am and spending the afternoon outdoors without reapplying.
• Counting on the SPF in a foundation or a day cream, applied in a thin layer.
• Keeping an opened bottle in a hot car all summer: heat can degrade the filters, so check the date after opening.

Sunscreen with the rest of your routine

Put sunscreen last, after serum and moisturiser, and wait a minute before makeup. It pairs well with a vitamin C serum in the morning. Exfoliating acids (glycolic, lactic, salicylic) and retinoids make the skin more sensitive to the sun, and many anti-spot routines only work with daily SPF, so sunscreen is not optional with those.

In Tunisia

Skinify lists the sunscreens available in Tunisia with their price in dinars: sunscreens, care for oily skin (fluids and gels) and anti-dark-spot care, delivered to all 24 governorates with cash on delivery.