Patch-testing Korean serums: jaw, not your whole face 패치 테스트
A Korean-sensible patch test is a thin layer of the new serum on a small area of jaw or inner arm for a couple of nights before the whole face. Stinging, welts, or delayed redness means stop. A tingle from a low-pH toner is not automatically an allergy, but spreading a new active everywhere on day one is how people confuse irritation with 'purging'.
Where and how long
Jawline or behind the ear, once or twice a day, for two or three days. If you have very reactive skin, longer. Do not patch-test on broken skin.
One new thing
If you start three new Olive Young bottles on the same night, you will not know which one caused the problem. Korean routines add slowly for a reason.
What a fail looks like
Itching, swelling, hives, or spreading redness. Stop and, if it is more than mild irritation, talk to a clinician. This page is not an allergy clinic.
Fragrance and essential oils
Some Korean formulas are fragrant. Sensitive shoppers often look for 무향 or fragrance-free lines. That is a shopping filter, not a medical guarantee.
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✍️ Written & reviewed by the KoreaPlus Editorial team — dermatologist-informed, cosmetic-science researched & source-cited. Last reviewed: 2026-08-29.
General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.