Sunscreen types

Main

Sunscreen is a topical product designed to protect the skin from the harmful effects of ultraviolet (UV) radiation, which can cause sunburn, premature aging, and skin cancer. There are two main types of sunscreens: mineral and chemical. These types may be combined in one product for enhanced protection.

• Mineral sunscreens (physical sunscreens): Contain inorganic compounds like zinc oxide and titanium dioxide that sit on the skin's surface and reflect UV rays. They offer immediate protection and are less likely to irritate sensitive skin, but can leave a white cast and may feel heavy on the skin.

• Chemical sunscreens: Contain organic molecules such as avobenzone and oxybenzone that absorb UV radiation and convert it into heat. They are easier to apply and have a lightweight feel, but can irritate sensitive skin and may take 15-30 minutes to become effective.

For example, when choosing a sunscreen for a baby, it is recommended to use a mineral sunscreen with zinc oxide or titanium dioxide, as their skin is more sensitive and prone to irritation.

Terms

• Avobenzone: An organic compound used in chemical sunscreens to absorb UV radiation.

• Broad-spectrum: A term used to describe sunscreens that protect against both UVA and UVB rays.

• Skin cancer: A type of cancer that develops in the cells of the skin, often caused by excessive exposure to UV radiation.

• SPF: Sun Protection Factor, a measure of how well a sunscreen protects against UVB rays. The SPF number indicates how long it would take for UVB rays to redden your skin compared to not wearing sunscreen. For example, SPF 30 means it would take 30 times longer to burn.

• Titanium dioxide: An inorganic compound used in mineral sunscreens to reflect and scatter UV rays.

• UVA: Long-wave ultraviolet radiation that penetrates deep into the skin and can cause premature aging and skin cancer.

• UVB: Short-wave ultraviolet radiation that causes sunburn and can also contribute to skin cancer.

• Zinc oxide: An inorganic compound used in mineral sunscreens to reflect and scatter UV rays.

Analogy

Think of sunscreens like umbrellas for your skin. Mineral sunscreens are like a solid, opaque umbrella that blocks the sun's rays from reaching your skin. Chemical sunscreens are like a clear umbrella that absorbs the sun's rays and converts them into heat. Just as you would choose an umbrella based on the weather and your preferences, you can choose a sunscreen based on your skin type and needs.

Misconception

Many people believe that applying sunscreen once a day is enough to protect their skin from UV damage. However, sunscreen should be reapplied every two hours, especially if you are swimming or sweating. For example, if you apply sunscreen in the morning and spend the day at the beach, you should reapply it multiple times throughout the day to maintain protection.

History

1. 1938: Franz Greiter develops the first sun protection factor (SPF) scale.

2. 1944: Benjamin Green develops a petroleum jelly-based sunscreen for soldiers during World War II.

3. 1980s: The FDA begins regulating sunscreens as over-the-counter drugs. Chemical sunscreens become more popular.

4. 1990s: Broad-spectrum sunscreens that protect against both UVA and UVB rays become available.

5. 2000s-present: Concerns arise over the safety and environmental impact of some chemical sunscreen ingredients, leading to increased interest in mineral sunscreens and the banning of certain ingredients in some locations. Mineral sunscreens, which have been used since ancient times, regain popularity.

How to Use It

1. Apply sunscreen generously to all exposed skin 15-30 minutes before going outside, and reapply every two hours or immediately after swimming or sweating excessively. Use about 1 ounce (a shot glass full) to cover your entire body.

2. For babies and young children, use a mineral sunscreen with zinc oxide or titanium dioxide, as their skin is more sensitive. Apply sunscreen to all exposed areas, including the face, ears, and neck.

3. Choose a sunscreen with an SPF of at least 30 and broad-spectrum protection. If you have sensitive skin, opt for a mineral sunscreen with zinc oxide or titanium dioxide.

Facts

• No sunscreen can block 100% of UV rays. SPF 30 blocks about 97%, while SPF 50 blocks about 98%.

• The SPF number indicates how long it would take for UVB rays to redden your skin compared to not wearing sunscreen. For example, SPF 30 means it would take 30 times longer to burn.

• The FDA requires sunscreens to remain stable and at their original strength for at least three years.

• Some chemical sunscreens, such as oxybenzone and octinoxate, have been shown to harm coral reefs and are banned in some locations.

• Wearing sunscreen daily can reduce your risk of skin cancer, premature aging, and sunburn.