SPF 101: Summer Protection, Reapplication, & Why Your Sunscreen Matters

We all know sunscreen is a non-negotiable, all-year-round essential. But when the sun’s blazing, does slathering on a higher SPF mean better protection? Not exactly. SPF—a.k.a Sun Protection Factor—measures how well sunscreen shields your skin from harmful UV rays. And while it’s tempting to grab that SPF 100 bottle, the truth is, the numbers don’t tell the full story.

What Do SPF Numbers Actually Mean?

You’d think SPF 100 offers twice the protection of SPF 50, right? Not quite. The difference is way smaller than you’d expect: SPF 30 blocks 97% of UVB rays, SPF 50 blocks 98%, and SPF 100 blocks 99%. Tiny margins, but all three still leave a small percentage of UV exposure. That’s why reapplication is key—especially if you’re outside for long periods.

Dr. Sejal Saheta, dermatologist and venereologist at InUrSkn, explains, “If your skin burns in 10 minutes without sunscreen, an SPF 15 sunscreen will extend that protection to 150 minutes. But real-life factors like sweat, water, and rubbing mean you should always reapply every two to four hours.” The takeaway? Don’t rely on numbers alone—consistency is everything.

Are There Downsides To High SPF?

While high SPF isn’t harmful, it can give a false sense of security. You might think SPF 100 means you can apply once and be good for the day—not true. Higher SPF mainly offers extended UVB protection, but it doesn’t necessarily mean better UVA defense.

UVA rays are sneaky. They penetrate deeper into your skin, breaking down collagen, accelerating ageing, and increasing skin cancer risk. If your sunscreen isn’t broad-spectrum (aka covering both UVA and UVB), even SPF 100 won’t cut it.

Another thing? If you have a deeper skin tone, spending extra on high-SPF sunscreens may not be necessary. Dr. Sejal adds, “Higher SPF formulas are often pricier and less available, but they don’t necessarily offer better protection for darker skin tones.”

How To Pick The Right Sunscreen

One golden rule: broad-spectrum is a must. This means your sunscreen protects against both UVA and UVB rays. Look for a PA rating (Protection Grade of UVA), which ranges from PA+ to PA++++: the more plus signs, the better the UVA protection.

There are, of course, some insider secrets we've got for you to nail the SPF game. Keep these in mind, and you're golden.

• Cream-based sunscreens for dry skin.

• Gel or water-based sunscreens for oily or acne-prone skin.

• Two finger lengths of sunscreen for your face and neck (don't act surprised).

• Applying 30 minutes before sun exposure and reapplying every 2–4 hours.

And yes, even if it’s cloudy or you’re indoors—sunscreen is still a must.

Different Types of Sunscreen Formulations

Gone are the days of greasy, white-cast sunscreens. Now, SPF comes in so many forms, there’s zero excuse to skip it. Here’s what’s out there:

Beauty Of Joseon Relief Sunscreen Rice + Probiotics SPF 50+ PA++++

A slightly creamier formulation, this one's classic, hydrating, and great for dry skin.

Available here.

Sulwhasoo UV Daily Fluid Sunscreen SPF 50+ PA+++

Lightweight, non-greasy, and perfect for oily or acne-prone skin.

Available here.

iS Clinical PerfecTint Powder SPF 40

A game-changer for reapplying over makeup. Think of it like setting powder but with UV protection—AND this one has a tint to give you an even complexion.

Available here.

Avene Very High Protection Sunscreen Spray SPF 50+

Super convenient for reapplication, but make sure you apply a ton (and rub it in!). This is my favourite way of topping up on SPF, just because it makes you feel so damn refreshed. 

Available here.

Thank You Farmer Korean Sun Stick SPF50+ PA++++

Easy to carry and mess-free, this one's ideal for quick touch-ups.

Available here.

Re'equil Sheer Zinc Tinted Sunscreen

You know how you're sometimes afraid to use sunscreen and your base makeup together? Tinted variations of SPF offer sun protection and even out skin tone—bye-bye foundation!

With all these options, there’s no reason to skip SPF—find one that works for you and make it a daily habit. Your future skin will thank you.

Available here.