Physical sunscreens are safe for sensitive skin but can be more greasy and runny than chemical sunscreens.
Sunlight contains many types of rays with different wavelengths, of which ultraviolet A (UVA) rays can cause skin aging such as wrinkles, age spots and can penetrate glass. Ultraviolet B (UVB) rays cause sunburn but cannot penetrate glass. People exposed to both types of UV rays are at risk of skin cancer.
There are two main types of sunscreen: mineral (physical) sunscreen and chemical sunscreen. Both are capable of protecting against the harmful effects of ultraviolet rays if chosen with a broad spectrum, used correctly and suitable for your skin type.
Physical sunscreen
Physical sunscreens work by scattering and reflecting the sun’s UV rays away from the skin. They contain titanium dioxide, zinc oxide, or sometimes both. In older sunscreens, these particles were often large and white or milky when applied to the skin.
A newer form of physical sunscreen is micronized sunscreen, which uses similar ingredients but is formulated as nanoparticles, which are smaller and more transparent to the skin. These sunscreens still reflect sunlight, but work primarily by absorbing UV rays before they can damage the skin.
Advantage:
Suitable for people with sensitive skin or uneven skin tone.
Contains zinc oxide and titanium oxide, substances listed as safe by the US Food and Drug Administration (FDA).
Protects skin from both UVA and UVB rays.
Skin protection depending on dosage used.
Defect:
Can leave white cream on skin.
Causes a sticky feeling.
Chemical sunscreens need to be reapplied more often because they can dissolve in water or sweat.
Use a broad-spectrum sunscreen with a sun protection factor (SPF) of 30 or higher. Photo: Ngoc Pham
Chemical sunscreen
Chemical sunscreens contain chemicals that absorb the sun’s ultraviolet rays before they can damage the skin. The rays are released from the skin as heat.
The FDA and experts have been studying chemical sunscreens for years to assess their safety. In 2020, a project conducted 29 studies to examine the effects of two ingredients in chemical sunscreens, oxybenzone (BP-3) and octinoxate (OMC). The review found that these chemicals do enter the bloodstream but do not appear to cause health problems. However, experts say more research is needed.
Since 2019, the FDA has also banned two ingredients previously used in chemical sunscreens: PABA and trolamine salicylate.
Advantage:
Easy to use and comes in many different forms such as spray, cream, lotion.
Non-sticky on skin.
Protects against both UVA and UVB rays.
Water resistant.
Protects skin longer than mineral sunscreens.
Defect:
Must be applied 15-30 minutes before sun exposure for effectiveness.
May cause irritation to sensitive skin or allergic reactions.
The safety of the chemical ingredients is of concern.
In addition to the two types of sunscreens above, there are also types that contain both mineral and chemical ingredients. Regardless of which type you use, everyone should choose a broad-spectrum sunscreen that protects against both UVA and UVB rays, with a sun protection factor (SPF) of at least 30.
People with darker skin tones or uneven skin tone may want to consider using a tinted sunscreen with iron oxide or titanium dioxide pigments. Tinted sunscreens protect against visible light, as well as UVA and UVB rays. Visible light can darken or darken the skin.
Apply sunscreen evenly to exposed skin and reapply every two hours, after swimming or sweating heavily.
To protect your skin, wear hats, long sleeves, and sunglasses when outdoors. Wear clothing with an ultraviolet protection factor (UPF) and materials that are treated to block the sun. The darker the color and tighter the weave, the more protection it provides. Avoid going outside during peak UV hours between 10am and 4pm.