Do You Need Sunscreen if You are Indoors?

• Ultraviolet (UV) rays that are most damaging to the skin are the UVA and UVB types, which cause free radical generation, wrinkles, sagging, and sunburn, as well as skin cancer.
• UVA rays can pass through glass into buildings and houses, while blue light from cellphones and computer screens is also something to be concerned about. As such, even when at home, it’s a good idea to apply an appropriate amount of sunscreen.
• Choose a sunscreen that protects against both UVA and UVB radiation. You can find this by looking at the SPF and PA ratings, respectively. Choose an SPF of 30 or higher and a PA rating of 3+ or higher.

Generally, sunscreen is part of many people’s daily routine before leaving the house for work. But with more flexible work styles—such as working from home or spending extended time indoors—the question often arises: “If I’m staying home all day and not going out in the sun, do I still need to wear sunscreen?” 
 

Sun exposure is one of the major causes of damage to skin cells, causing the generation of free radicals, skin inflammation, loss of collagen, skin darkening or dark patches on the skin, melasma or freckles, and increasing the risk of skin cancer. Sunlight consists of visible light and invisible light, such as infrared light and ultraviolet rays or, as they are more commonly known, UV rays. 

There are three types of UV rays present in sunlight—UVA, UVB, and UVC. UVC radiation is mostly absorbed by the earth’s ozone layer, reflected, or completely destroyed, so it doesn’t have much effect on the skin. As such, for the purpose of this article, we will discuss the first two types—UVA and UVB—which play a major role in causing many different skin problems.  

1. Ultraviolet A or UVA Radiation can be subdivided into UVA I and UVA II. About 95% of the UV rays from the sun that reach the ground are UVA rays, and these are very harmful to the skin, causing wrinkles, sagging, fine lines, blemishes, and the generation of free radicals, indirectly causing DNA damage, genetic mutations, and some types of skin cancer.
2. Ultraviolet B or UVB Radiation is the type of radiation that causes sunburn, skin inflammation, and premature aging of the skin. It is also an important risk factor for skin cancer in cases of frequent exposure to sunlight, particularly during noon or early afternoon, when there are clear skies with few clouds, or when skin is not properly protected from the sun.

If you are working at home and are not going out at all, you may wonder: “Do I still need to apply sunscreen?” Some people may feel that if they will not be out in the sun, there’s no need to apply sunscreen. On the other hand, some people are concerned about the UV light from home appliances such as fluorescent lights, televisions, or computer screens.

In reality, these types of devices have virtually no radiation, or very low levels, if any. As such, they have no negative impact on the skin. Concern, however, should more likely be given to the UVA rays present in light that enters through windows or glass. Clear glass allows 75% of UVA through, while tinted and reflective glasses allow only 25%-50% of UVA rays to pass through. (UVB rays do not pass through window glass.)

Therefore, while household appliances hardly emit any UV rays at all, if you want to protect your skin from sunlight that could be coming through windows or glass in your home, it is recommended that you always apply sunscreen, even when indoors. Use a sunscreen with appropriate SPF and PA ratings (SPF 30 and PA 3+ or higher), and keep the curtains closed when possible. Try to sit as far away from open windows as possible, and avoid staying in spots where the sun is shining through. You can also switch to tinted glass instead of clear glass and/or install window protection films to filter out UVA rays that would otherwise pass through the glass windows. In this way, you can prevent UVA skin damage.

• Choose a sunscreen that protects against both UVA and UVB radiation. You can find this by looking at the SPF and PA ratings, respectively. Choose an SPF of 30 or higher and a PA rating of 3+ or higher (According to EU standards for principles of sunscreen product development).
• Choose a product with the texture and properties to suit the activities you will be doing. If you are working at home, it’s recommended that you use a sunscreen with a texture comfortable to your skin, not too thick or heavy on the skin, and one that does not cause pore-clogging. In this case, it may not be necessary to use waterproof or sweat-proof sunscreens if you will not be engaging in activities that cause perspiration.
• Choose a sunscreen suitable to your skin type. For example, if you have oily skin, use a gel or a lotion, or whatever texture you find is comfortable for you.
• Choose a sunscreen that can protect your skin from any direct exposure to infrared radiation (IR), also known as heat radiation, and from blue light (BL) from computer screens, mobile phones, and tablets.
• Select sunscreens that do not contain occlusive agents, such as lanolin or propylene glycol, which can clog pores and cause acne.
• If, after using a particular sunscreen, you have a negative result or an allergy or rash, stop using it immediately.
• Choose sunscreens free from preservatives and fragrances. 

Oral Sunscreen (Dietary Supplements for Sun Protection)

These provide additional protection from within the body. They cannot replace topical sunscreen but can help enhance skin protection, such as:

• Polypodium Leucotomos Extract (PLE): A fern extract that research has shown may reduce skin inflammation caused by sunlight, lower the risk of sun-induced rashes, and decrease DNA damage.
• Astaxanthin, Beta-Carotene, Lycopene: Antioxidants that help minimize the harmful effects of UV radiation on the skin.
• Vitamin C and Vitamin E: Work together to reduce damage caused by free radicals.
• Nicotinamide (Vitamin B3): May help reduce the risk of skin cancer in individuals at high risk.

Oral sunscreens cannot substitute for topical sunscreen. For best results, both should be used together.

• If you are working from home, are in the shade at all times, and are not perspiring, it may not be necessary to reapply sunscreen every two hours. If you do need to go out in the sun, however, you should reapply sunscreen every two hours, regardless of the SPF or PA ratings of the sunscreen.
• The appropriate amount of sunscreen that should be applied to the face in one application is at least 2 milligrams of sunscreen, sometimes known as the “two-finger” approach, or roughly the size of a 10 baht coin. If the sunscreen is in liquid or spray form, it should be used in larger quantities than the cream form.
• In addition to your face, don’t forget to apply sunscreen to your neck, ears, and any exposed parts of your body. 
• If you are using chemical sunscreen, it should be applied at least 30 minutes before going out into the sun. Physical sunscreen can be applied just before exposure to the sun.

As you can see, sunscreen acts as a shield to protect against skin damage caused by the sun’s UV rays. As such, it’s recommended that you apply sunscreen with the appropriate SPF and PA ratings every day, even when you are planning to work or stay home. This should be complemented by other forms of protection such as window films to filter light coming through the glass. Taken together, all of these measures will help protect your skin from wrinkles, blemishes, and premature skin aging.