Most people apply sunscreen for a day outside and skip it on a day at the desk.
So, do you need sunscreen indoors? Yes, if you sit near a window or work in a daylight-lit room. Window glass blocks most UVB but lets a large share of UVA through. UVA drives collagen breakdown and pigmentation.
If you spend the whole day in a windowless room, you have little to protect against.
What does window glass block?
Two types of UV light reach the ground. UVB causes sunburn. UVA penetrates deeper, into the dermis where collagen sits.
UVA drives photoageing, which is skin ageing caused by sun exposure. It also deepens pigmentation.
Standard window glass blocks most UVB. It transmits much of the UVA. That is why you do not burn at a desk, but your skin can still age there. Car side windows work the same way.
UVA also stays fairly constant through the day and across seasons. In Malaysia and Singapore, that means year-round exposure.
Does screen light damage your skin?
Screens emit visible light, including blue light, at far lower intensity than sunlight. Evidence that screens damage skin in real-world use is limited.
Daylight is the bigger exposure. Visible light from the sun can worsen pigmentation in darker skin tones. Tinted sunscreens containing iron oxides help block it.
When do you need sunscreen indoors?
Wear sunscreen if you:
- Sit near a window
- Work in a room with strong daylight
- Commute by car, bus or train in daytime
- Step outside at any point before dusk
- Use retinoids or exfoliating acids, which make skin more sun-sensitive
Skip it only if you stay in a windowless or fully curtained room all day. Even then, one trip outside cancels that plan.
How do you apply sunscreen on an indoor day?
- Choose broad-spectrum SPF 30 or higher. SPF (sun protection factor) measures UVB protection. Broad-spectrum means it also covers UVA. Check for a PA rating, which measures UVA protection. Our Tribiotics 360° Suncare is one option.
- Apply it as your last morning skincare step. Put it on after moisturiser.
- Use enough. About a quarter teaspoon covers the face and neck.
- Reapply if you go outside. One morning application is usually enough for a full indoor day.
Does daily sunscreen really slow visible ageing?
Yes. In a randomised trial in Australia, adults who used sunscreen daily for four and a half years showed less skin ageing than adults who used it at their own discretion.
Consistency matters more than intensity. Skipping "boring" indoor days adds up.
Explore our daily suncare range.
Daylight reaches your skin wherever there is a window, so daily sunscreen belongs in every routine.