Yuzu
Also known as: Citrus junos, Japanese Citrus
The Japanese winter citrus Tatcha keeps in the hero slot of its barrier serum — and the Japanese soak in on winter solstice.
What It Does
Deep Dive
Citrus junos is a sour, knobbly Japanese citrus with an unmistakable floral-citrus scent. Beyond the bathtub tradition of yuzu-yu (winter solstice yuzu bath), its extract appears across modern J-beauty as an antioxidant brightener. Chemistry: high vitamin C in the fruit juice, limonene and hesperidin in the peel, plus nomilin and nobiletin (citrus flavonoids with documented anti-inflammatory activity). Clinical data is limited but the antioxidant case is legitimate. Caveats: citrus peel oils contain furocoumarins that can cause photosensitivity at high concentration, which is why responsible J-beauty brands (Shiseido, Tatcha, THREE) use it in leave-on serums at <2%. Yuzu bath products have no such issue — you rinse off.
