Understanding Your Sunscreen

At some point, most of us would have visited a pharmacy outlet to purchase a sunscreen, only to find ourselves being bombarded with choices. Hence, understanding how sunscreen works would help us select one that is most suitable for the occasion.

How does Sunscreen Work?

Sunscreen protects the skin against harmful ultraviolet (UV) rays, with UVB rays being the culprit for sunburns. While both radiations may lead to skin cancer, UVA penetrates deeper into skin layers, resulting in premature wrinkling and age spots. Nevertheless, a broad-spectrum of sunscreen protects against both types of UV rays.

Sunscreen works differently, depending on the chemical content. Inorganic chemicals, such as zinc oxide or titanium dioxide, reflect UV rays from skin; meanwhile, organic chemicals, including avobenzone or oxybenzone, absorb UV radiation and release heat as the sunscreen component breaks down.

What does SPF Mean?

Sun protective factor (SPF) is the length of time required for skin to burn with sunscreen application as compared to without. Simply put, if the skin starts to redden after 10 minutes of sun exposure, a SPF 10 sunscreen would allow sun exposure of 100 minutes (10 times longer) before the skin reddens. Thus, protection against UVB rays is indicated by the SPF level.

The categories of UVB protection are shown as follows:

When properly applied, a medium coverage provided by SPF 15  can block 93% of UVB rays, while SPF 30 can filter 97% of UVB rays.  However, beyond SPF 30, a higher SPF level only provides marginally better sunburn protection. For example, SPF 50 provides 98% UVB protection, while SPF 100 blocks 99%. Therefore, SPF 30 or SPF 50 is adequate for sun protection.

How to Apply Sunscreen?

Sunscreen should be applied evenly and generously on exposed skin 30 minutes before sun exposure. Regardless of SPF protection, the same amount should be reapplied within two hours, or immediately after swimming or excessive sweating.

Bottom line:

Always opt for a sunscreen that has a broad spectrum protection and is water-resistant, with protection of SPF 30 and above. Nevertheless, if severe sunburns occur despite proper prevention measures with the presence of high fever, extreme pain, headache, or large blisters, medical attention is warranted. If you would like to see a doctor, book your appointment with GetDoc — a platform that allow users to schedule visits with panel doctors.

References:

1. Which sunscreen should I use?
2. What’s wrong with high SPF?
3. How does sunscreen work?

Tags

• SPF
• Sun protection
• sunscreen
• UV rays
• UVB