Health authorities advise that most individuals do not apply adequate amounts of sunscreen for effective skin protection. The National Health Service (NHS) recommends that adults use approximately six to eight teaspoons of sunscreen to cover their entire body when exposed to the sun.
Sunscreen should be applied to all exposed skin areas, including the face, neck, ears, and the head if hair is thin or absent. Application ideally should occur 30 minutes before going outdoors. Reapplication is necessary every two hours, or more frequently if sweating heavily, after swimming, or after towel-drying. This guidance applies even to sunscreens labeled as water-resistant or long-lasting.
However, no sunscreen can provide complete protection against UV radiation. To enhance protection, it is recommended to wear clothing such as trousers, skirts with opaque fabric, long-sleeved tops, sun hats, and sunglasses. Additionally, seeking shade during the hottest parts of the day is advised.
Sunscreen efficacy is often described by its Sun Protection Factor (SPF), with ratings generally categorized as low (SPF 6-14), medium (SPF 15-29), high (SPF 30-50), and very high (SPF 50+). Higher SPF numbers indicate greater protection against sunburn. The star rating system on sunscreen products indicates the level of broad-spectrum protection against both UVA and UVB rays, with higher star ratings signifying better protection.