SPF (Sun Protection Factor) — Ingredients

Category: Ingredients

An international standard index indicating how well a sunscreen blocks UVB rays

What is SPF (Sun Protection Factor)?

An international standard index indicating how well a sunscreen blocks UVB rays

SPF 30 blocks about 97% of UVB, while SPF 50 blocks about 98%. PA indicates the UVA protection grade.

Main causes & characteristics of SPF (Sun Protection Factor)

SPF (Sun Protection Factor) is an internationally recognized index that indicates how effectively a sunscreen shields the skin from UVB rays, which are responsible for causing redness and burning. SPF 30 is known to block approximately 97% of UVB rays and SPF 50 approximately 98%; the protection rate does not increase proportionally with higher numbers. PA is a separate rating system — expressed with plus signs — that indicates the degree of protection against UVA rays, which penetrate deeper into the skin.

Managing SPF (Sun Protection Factor)

It is recommended to apply a sufficient amount (approximately the size of a 500-won coin for the face) evenly 20 minutes before going outdoors. Because the protective layer is removed by sweat, water, and friction, reapplying every two to three hours during outdoor activities is advisable. Checking both SPF and PA ratings to select a broad-spectrum product that covers both UVB and UVA may be beneficial.

Related information

SPF is discussed alongside the PA rating, UVA and UVB, inorganic (mineral) and organic (chemical) sunscreen filters, and the concept of broad-spectrum protection.

Everyday care tips

UV rays penetrate even on cloudy days and through indoor windows, so it is advisable to apply sunscreen every day throughout the year and to remember often-missed areas such as the backs of the hands, the neck, and the ears.

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Frequently Asked Questions (FAQ)

What is SPF (Sun Protection Factor)?
An international standard index indicating how well a sunscreen blocks UVB rays SPF (Sun Protection Factor) is an internationally recognized index that indicates how effectively a sunscreen shields the skin from UVB rays, which are responsible for causing redness and burning. SPF 30 is known to block approximately 97% of UVB rays and SPF 50 approximately 98%; the protection rate does not increase proportionally with higher numbers. PA is a separate rating system — expressed with plus signs — that indicates the degree of protection against UVA rays, which penetrate deeper into the skin.
Managing SPF (Sun Protection Factor)
It is recommended to apply a sufficient amount (approximately the size of a 500-won coin for the face) evenly 20 minutes before going outdoors. Because the protective layer is removed by sweat, water, and friction, reapplying every two to three hours during outdoor activities is advisable. Checking both SPF and PA ratings to select a broad-spectrum product that covers both UVB and UVA may be beneficial.

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Medical Disclaimer

SKINROUTE is not a medical device. All content is provided for general skincare information purposes only and does not replace medical diagnosis or treatment. If you suspect a skin disease, please consult a board-certified dermatologist.