Most sunscreen shopping outside Korea trains you to look for one number. Walk up to a Korean sunscreen shelf and there are two printed side by side, and only one of them looks familiar.
One-line definition: SPF blocks UVB, PA blocks UVA
SPF, Sun Protection Factor, measures how well a product shields skin from UVB, the shorter wavelength responsible for sunburn. PA, Protection Grade of UVA, measures a separate defense against UVA, the longer wavelength tied to pigmentation changes and loss of elasticity over time. Both numbers sit on the same Korean sunscreen label, but they're answering two different questions about two different kinds of damage.
A shopper who only recognizes "SPF 50" from sunscreen bought at home can walk straight past the "PA++++" printed next to it without registering that it's a second, separate rating worth checking. PA almost never shows up on Western sunscreen packaging, so there's no habit built up around reading it — until a Korean shelf puts it directly in front of you.
How the PA+ to PA++++ scale works, and why it isn't "broad spectrum"
PA is graded on a four-step scale: PA+, PA++, PA+++, and PA++++, with each additional plus sign representing stronger measured protection against UVA. The grading comes from the PPD test, short for Persistent Pigment Darkening, which measures how much a controlled UVA dose visibly darkens skin pigment over a set period of time.
That's a different lab method entirely from the pass/fail "broad spectrum" label used on US sunscreen, which confirms a minimum level of UVA coverage exists without disclosing how strong it is. A Korean PA++++ product and a US "broad spectrum" product can both claim solid UVA defense while having been tested through two different systems that don't translate into each other on a one-to-one basis.
For everyday walking around a city, PA++ or PA+++ generally covers a normal amount of incidental exposure; a beach day, a hike, or hours outdoors in direct sun is where shoppers usually reach for PA++++ specifically. Neither choice is wrong on its own — it's a question of matching the grade to how much of the day is actually spent outside.
Why UVA protection matters even without direct sun
UVA exposure is linked to pigmentation changes and a gradual loss of skin elasticity, a slower kind of damage than the burn UVB causes. The distinction that trips people up: UVA passes through window glass and cloud cover, both of which block a meaningful share of UVB.
That means a day that never involves standing in direct sunlight can still deliver real UVA exposure. A window seat on a KTX ride between cities, an afternoon at a café table by the glass, or a fully overcast sightseeing day in Seoul all count, with no sunburn afterward to signal that anything happened.
Mineral, chemical, or hybrid: what decides the white cast and the sting
Mineral filters, labeled 무기자차 (inorganic) on Korean packaging, sit on top of skin and are the type more likely to leave a visible white cast, especially on deeper skin tones. Chemical filters, labeled 유기자차 (organic), absorb into skin instead and are more likely to sting around the eyes or on already-irritated skin. Hybrid formulas blend both filter types to balance the two trade-offs.
The label detail worth remembering: a sunscreen sold as "physical" at Olive Young is usually marked 무기자차 in Korean rather than carrying the English word "mineral" anywhere on the front of the bottle. Same category, different language to search for if the front-of-pack English doesn't mention it. A hybrid formula sometimes carries both terms on the box, listed together rather than choosing one label over the other, since it's blending filters from each category into a single product.
How much to apply, how often to reapply, and reapplying over makeup
The lab that assigns an SPF number tests it using roughly 1/4 teaspoon of product spread across the full face, close to the size of a 500-won coin poured into your palm. Most people apply far less than that in daily life, closer to how a moisturizer gets swiped on, which means the real-world protection often falls short of the number printed on the tube.
Reapplication is generally recommended roughly every two hours during direct outdoor exposure, and again after sweating heavily or swimming. Cushion compacts, sunscreen sticks, and setting mists are built for touching up that base layer over makeup during the day — none of them are formulated to replace the first full application done before makeup goes on.
Buying and packing Korean sunscreen to take home
Most Korean sunscreen comes in 50ml tubes at the smaller end, with plenty of full-size bottles running well past 100ml. At Incheon Airport security, carry-on liquids need to sit at 100ml or less per container and fit together inside a single 1-liter clear zip bag — a rule based on the container's printed size, not how much product is actually left inside it.
A 50ml tube clears that limit with room to spare. An unlabeled tester or sample bottle with no printed capacity at all is the one that tends to get pulled aside for a closer look at screening, regardless of how little liquid is inside. Checked luggage carries no such container-size limit, which is the simpler route for a full-size bottle bought to take home rather than to use during the trip.
A sunscreen bought after security, at an airport duty-free counter, is a separate case again — it's typically sealed in a tamper-evident bag with the receipt visible, which can allow it past the container-size rule on the flight actually being boarded. That bag isn't something to open before landing, and a connecting flight through a second airport can still mean a second liquid check, so confirm the current rule for the specific route rather than assuming the sealed bag clears every leg automatically.
The misconception: a high SPF number doesn't guarantee high UVA protection
The single most common misread of a Korean sunscreen label is treating a high SPF number as proof the whole bottle offers strong protection across the board. SPF 50 says nothing about the PA grade sitting right next to it — a bottle can carry SPF 50 and only PA++, leaving UVA coverage weaker than the headline number would suggest.
Checking both numbers separately, every time, is the only way to know actual UVA coverage rather than assuming one high figure covers for the other. A quick habit fixes this at the shelf: read the SPF number, then look for the PA rating printed beside or beneath it before deciding a bottle offers full protection.
Skin that's recently had a laser session, a peel, or another in-clinic procedure needs sun-exposure guidance from the treating doctor rather than a general SPF/PA recommendation, since healing skin can react differently to both UVB and UVA exposure than skin that hasn't been treated.