Wearing SPF Inside Sounds Silly—Until You Read This

When we hear the word "sunscreen," our mind automatically thinks of a beach vacation, a warm sunny day, or poolside. But what if sunscreen isn't just to be used when you’re outdoors alone? What if applying SPF is just as important on cloudy days or even when working from home?

Sunscreen is quite possibly the most powerful tool in our skincare routine. Nevertheless, even with all the advice given, individuals remain confused regarding when and where to apply SPF. The query remains: do you really need to use sunscreen daily, even when indoors?

Let's separate the science, myths, and specialists’ take to understand why sunscreen is more than a summertime necessity.

Why Sunscreen Is an All-Year-Round Must

Sunscreen does not just shield us from sunburns; it is also crucial in helping maintain our skin's overall health in the long term. "Sun exposure is the number one extrinsic factor that drives skin ageing," says Manuela Marcheggiani, CEO and Co-Founder of Isomers Skincare Laboratories.

She characterises sun rays, UVA and UVB rays, specifically, as small scissors that cut through the skin's collagen fibres, cutting through our skin. The result? Fine lines, wrinkles, sagging skin, and discolouration. "Imagine someone cutting your favourite sweater with scissors," she says. "That's what UV rays do to your skin."

But it does not stop with beauty routines alone. Exposure to UV light also leads to skin cancer development. When UV light penetrates the skin, it can damage the DNA, which can lead to abnormal cell growth and eventually cancerous changes.

In summary, she says, " Sunscreen is both a beauty item and a health item.”

SPF Indoors: Do You Really Need It?

Applying sunscreen indoors seems illogical, but professionals do not agree.

1. UVA Rays Penetrate Glass

Dr. Mamina Turegano, a triple board-certified dermatologist, explains that UVA rays, the type responsible for premature ageing and some skin cancers, can pass through window glass. So even if you’re indoors, you’re not completely shielded.

“Just walking from your front door to your car, retrieving your mail, or sitting in a sunny window puts you under UVA exposure," she explains. Each of these tiny, repeated exposures year after year accumulates and causes tremendous sun damage, even if you have never gotten a sunburn.

2. UV Damage due to Screens

Another frequently neglected source? Computer screens. Dr Munir Somji of Dr Somji Pro-Active Skincare explains that blue light (HEV light) from phones, laptops, and tablets can cause skin damage. Findings indicate that HEV light can cause hyperpigmentation and premature ageing.

Even in a darkened room, the screen before you may be affecting the health of your skin. Wearing sunscreen is a form of protection, especially products specifically designed to block HEV light as well.

The Long-Term Effects of Not Wearing SPF

You might be thinking, "I'm only outside in the sun for a few minutes a day. How bad can it be?"

Dermatologists advise that it's not so much a question of how intense the exposure is at any single moment. Instead, it's the cumulative effect. All those fleeting seconds a day over the years can result in:

• Collagen breakdown

• Fine lines and wrinkles

• Sunspots or hyperpigmentation

• Greater risk of skin cancer

• Thinning skin and impaired skin texture

How Often Should You Apply Sunscreen

Sunscreen must be applied daily when there is any exposure to the sun's UV, regardless of the season, Marcheggiani says. Even on overcast days, as much as 80% of the UV rays come through.

She suggests reapplying it every two or three hours, especially if you're outside or in a light-filled room with many windows.

Tip: If you're indoors all day and away from screens or windows, you might be able to get away without reapplying, but for us in Nigeria, that's not an option.

You should also learn your location's UV index. Even in harmattan or rainy periods, UV radiation exists, and sun exposure should still be considered.

Choosing the Right SPF

In choosing a sunscreen, the following are important factors to consider:

• Broad-spectrum: Protects against both UVA and UVB radiation.

• SPF 30 or more: Minimum SPF 30 is what dermatologists recommend using daily.

• Non-comedogenic: Ideal for oily or acne-prone skin.

• Tinted SPF: Can offer extra protection against HEV light from screens.

When You Don't Need Sunscreen

There are a few instances when you might not need sunscreen, such as:

• Remaining in a room with no windows and no exposure to the sun

• Working indoors within a dark, non-exposed room

• Sleeping or napping indoors with no electronics or screens

But for many of us, commuters, remote workers, students, office workers, and even stay-at-home parents, daily exposure to some form of UV radiation is inevitable.

Yes, You Really Do Need SPF Every Day

Wherever you are, outside on a sunny or cloudy day, at work near windows, or even just browsing on your phone, your skin is being exposed to environmental stressors that speed up ageing and stimulate skin cancer.

Sunscreen is not a seasonal thing you slap on during the summer; it's a daily protector. It's backed by science, dermatologists, and formulators to make it one of the easiest, most efficient ways of safeguarding your skin health and appearance in the long term.

So, yes, you absolutely do need to use sunscreen daily, even while indoors. Check out these 11 Korean sunscreens to make SPF the best part of your skincare routine.