Sunlight is a primary cause of skin darkening, hyperpigmentation, premature aging, and skin cancer. UV damage to the skin is cumulative, silently occurring over many years before manifesting as hyperpigmentation, darkening, wrinkles, or skin cancer.

Doctor Nguyen Thi Viet Ha, from Tam Anh Cau Giay General Clinic, states that sun protection is a lifelong habit, not just for summer or travel.

Daily use

Ultraviolet (UV) rays in sunlight include UVA and UVB. UVB is the main cause of sunburn, while UVA penetrates deeper, destroying collagen, promoting aging, and stimulating melanin production, leading to hyperpigmentation and skin darkening. UVA is present year-round, penetrates clouds and windows, and affects the skin even on cloudy days or when sitting indoors near a window. Therefore, sunscreen should be used daily, not just on intensely sunny days or when going outdoors.

Doctor Ha examining and advising on skin care. *Illustration: Tam Anh Cau Giay General Clinic*

Apply sufficient quantity

According to recommendations from the U.S. Food and Drug Administration (FDA), the amount of sunscreen needed per skin area is 2 mg/cm2. The "two-finger rule" (squeezing a line of cream the length of your index and middle fingers) can be applied to determine the amount of sunscreen to apply to the face and neck. If applied too thinly, the protective effect significantly decreases, even with a high SPF product.

Apply 15-20 minutes before going outside

Sunscreen needs to be applied about 15-20 minutes before sun exposure. After two to three hours, the cream's effectiveness on the skin diminishes due to sweat, oil, and friction, requiring reapplication. If engaging in outdoor activities, sweating heavily, or swimming, reapplication is needed sooner. Applying sunscreen only once in the morning or only after going outdoors, when the skin has already been directly exposed to UV rays, is not enough to protect the skin all day.

Foundation with SPF is not enough

Some people believe that makeup foundation with SPF is sufficient. In reality, foundation is often applied very thinly and does not reach the necessary amount for sun protection. Sunscreen should be used as a separate step before applying makeup.

Do not forget ears, neck, nape, and back of hands

Sunscreen should be applied not only to the face but also to the ears, neck, nape, and back of the hands – areas frequently exposed to sunlight and prone to early aging.

Choose the right type

For oily, acne-prone skin, choose lightweight gel or milk formulas that do not clog pores. Dry skin can opt for cream formulas with added moisturizing ingredients. Sensitive skin should prioritize physical sunscreens containing zinc oxide or titanium dioxide to reduce the risk of irritation.

Combine with physical protection

Wide-brimmed hats, masks, and UV-protective clothing help reduce the amount of ultraviolet rays reaching the skin, providing maximum support for the protective cream layer. Relying solely on sunscreen in conditions of intense, prolonged sun is not enough.

For individuals undergoing treatment for hyperpigmentation, acne, or skin rejuvenation using high-tech laser devices like Fotona StarWalker or Fotona Dynamis, proper sun protection enhances treatment effectiveness. Without protecting the skin from UV rays, melanin production continues to be stimulated, reducing the efficacy of these treatments.

Doctor Ha notes that sunscreen has high adherence to remain on the skin, so proper makeup removal is essential to avoid clogged pores, which can lead to acne and dermatitis. Sunscreen has an expiration date and may lose effectiveness if stored in high temperatures. Avoid leaving sunscreen tubes in car trunks or in direct sunlight, as this can alter the product's ingredients.

Thanh Ba