How we test

"Test" on Seoulvanie means checking products against data, not trying them on skin. We judge Korean skincare with records from Korea: sales rankings, Korean ratings and reviews, ingredient lists and dated store checks. This page explains what we collect, how we date it and what we leave out. Each article also explains its own selection or comparison rules on the page.

We don't test products on our own skin

No page is based on our own use of a product, and we don't write "we tried it" or "on my skin". Comparisons, roundups and single-product pages say "Research-based — not personally tested" near the top. Where a page quotes Korean shoppers on texture, scent or feel, we translate the quote, name its platform and date, and label it "Not our own use".

What we collect in Korea

• Olive Young Korea sales rankings. We capture the ranking tab a page needs (skincare, cleansing, sun care, cushions and so on) and record the date; for the monthly ranking we also record the time in KST. When a page compares with an earlier date we didn't capture ourselves, it uses an Internet Archive copy of the same tab and says so.
• Hwahae ratings and review counts. We give the score, the number of reviews and the date we read them. Hwahae's review-topic counts are cited as mentions, not as reviews.
• Korean shoppers' reviews and surveys. Depending on the page: Olive Young Korea buyer surveys, Olive Young review samples (for example, how many carry the "repurchase" badge), Glowpick review tags, Naver Blog posts and reviews on brands' own stores. Each quote or count names its platform and date. Reviews on a brand's own store are labeled as not independent, and we note review events where we found them.
• Ingredient lists (INCI). The Korean list comes from the Olive Young Korea product notice or, if Olive Young doesn't carry the product, the brand's Korean store. Where a page compares formulas, we match it name by name with the list on an overseas store listing.

What we check in your market

• Store checks. Where a page tells you where to buy, we record which stores list the product, who sells it, where it ships from and the date we checked. On English pages these are US stores such as Amazon US, Olive Young US, Sephora US, Ulta and YesStyle; each page names the ones it checked.
• "Not found" has a rule. A product reads "not found" only when every store a page lists for that market came back empty after searches under at least two forms of its name, and the page names those stores and the check date. A store we didn't check is shown as not checked, never as "not found".
• Korean formula or not. A store's version can carry a different ingredient list from the Korean one under the same name. Where we compared, a listing is marked as the same formula, a different formula or not confirmed, and the finding covers only the listing we compared.
• Prices. In our Seoul-vs-US price comparison, every price was re-checked in a real browser on the dates shown, compared per 10 ml at the price you would have paid that day, and converted with one dated exchange-rate table. On every page, Amazon appears as a link only and is never priced, so "cheaper" means cheaper among the stores we compared.

Dates

Each rank, rating, price and store check carries the date of its own record, written like "1 Oct 2026". When one sentence uses two sources, each gets its own date. The "Updated" date on an article is the page date, not the date of each figure. What each Korean source can and can't tell you: About our Korea data.

When we can't confirm something

We say so. Instead of a guess, you'll see wording such as "not checked", "not compared" or "not confirmed". Figures printed by a brand, such as the amount of an ingredient on a label, are reported as the brand's declaration; we haven't verified them by independent testing.

What we don't judge

We don't make medical judgments. A ranking or a rating shows what Korean shoppers buy and say, not what a product does to skin. Questions about skin conditions, pregnancy or medication belong with a doctor.

How we keep this independent from brands and stores: Editorial policy and Affiliate disclosure.