Answer:

Even without makeup, cleansing before reapplying sunscreen mid-day is crucial. After several hours, especially in hot, humid weather, sunscreen mixes with sweat, sebum, and airborne pollutants. This can clog pores, increasing the risk of blackheads, whiteheads, or inflammatory acne.

For those with oily skin, clogged pores can occur within hours if skin isn't cleansed properly. Air pollution and PM2.5 further weaken the skin's natural barrier, accelerating aging and increasing wrinkles and pigmentation.

Sunscreen is vital for skin protection, minimizing UV damage like sunburn, melasma, premature aging, and DNA damage that increases skin cancer risk. Regardless of the type, experts recommend reapplication every 2 to 3 hours with direct sun exposure.

Dr. Quach Thu Trang examining a patient's skin. Photo: Tam Anh General Hospital

Dr. Quach Thu Trang examining a patient's skin. Photo: Tam Anh General Hospital

Before reapplying sunscreen, use a cotton pad dampened with water to gently wipe your face, focusing on the T-zone, which is prone to oiliness and dirt buildup. If your skin is very sweaty or oily, wash with a gentle cleanser and warm water for a clean, clear surface. Apply a thin layer of oil-free gel or lotion moisturizer to hydrate and soothe before sunscreen. Use a nickel-sized amount for your entire face for effective protection.

Avoid cleansers with drying alcohol, fragrances, or irritants, which can compromise your skin's protective barrier and increase sun sensitivity. Choose fragrance-free, pH-balanced cleansers to maintain moisture and ensure skin safety with frequent sunscreen reapplication.

Quach Thu Trang, MD, PhD

Dermatology Specialist

Tam Anh General Hospital, Hanoi