{"product_id":"cosrx-the-niacinamide-15-serum-20ml-mirai-skin-cosrx-the-niacinamide-15-serum-20ml","title":"COSRX The Niacinamide 15 Serum 20ml","description":"\u003ch2\u003eCOSRX The Niacinamide 15 Serum: The High-Strength Brightening Pick for Stubborn Pigmentation\u003c\/h2\u003e\n\u003cp\u003eCOSRX's Niacinamide 15 Serum is a high-percentage, no-frills brightening serum for users who've outgrown lower-strength formulas. At 15% niacinamide (versus the more common 5%), this is a clinical-strength dose that targets sebum control, pore minimization, and stubborn pigmentation faster than standard niacinamide products. It's also one of the few Korean brightening serums at this concentration sold at an accessible price.\u003c\/p\u003e\n\u003cp\u003eHonest context: 15% niacinamide is not for sensitive skin. Users new to the active should start at 5% or 10% (COSRX sells both) to build tolerance, then graduate to 15%. Flushing, mild tingle, and occasional breakouts during adjustment are common. Users who tolerate it get faster results on oily, pigmented, and texture-heavy skin than any other gentle-ish active on the market.\u003c\/p\u003e\n\u003ch3\u003eWhat It Does\u003c\/h3\u003e\n\u003cp\u003eNiacinamide (vitamin B3) works through multiple pathways: inhibits melanosome transfer (brightens), regulates sebum production (de-greases oily skin), strengthens the barrier, and reduces pore appearance. At 15%, these effects are visible in 4 to 8 weeks rather than 12 weeks. Zinc in the formula supports sebum control further.\u003c\/p\u003e\n\u003ch3\u003eWho It's For\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eStubborn hyperpigmentation or acne marks:\u003c\/strong\u003e Clinical-strength brightening dose.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOily skin with visible pores:\u003c\/strong\u003e Sebum control benefit.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNiacinamide tolerance builders:\u003c\/strong\u003e Graduate step from 5 or 10%.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePost-acne skin maintenance:\u003c\/strong\u003e Fades PIH while regulating oil.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBudget-conscious serum shoppers:\u003c\/strong\u003e High-strength at under $25.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eKey Specs\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eVolume: 20ml\u003c\/li\u003e\n\u003cli\u003ePrice: $24.96\u003c\/li\u003e\n\u003cli\u003eHero actives: 15% niacinamide, 0.5% zinc\u003c\/li\u003e\n\u003cli\u003eTexture: lightweight serum, fast-absorbing\u003c\/li\u003e\n\u003cli\u003eFragrance: fragrance-free\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eHow to Use\u003c\/h3\u003e\n\u003cp\u003eStart with every other evening for the first 2 weeks to build tolerance. Apply 2 to 3 drops to clean, toned skin. Pat in, follow with moisturizer. Once tolerated, use nightly or twice daily. Always pair with SPF (AM) when using brightening actives. Do not use alongside stronger acids on the same evening during tolerance building.\u003c\/p\u003e\n\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003ch4\u003eIs 15% too strong for me?\u003c\/h4\u003e\n\u003cp\u003eIf your skin is reactive, flushes easily, or you've never used niacinamide: yes, start with 5% first. If you've used niacinamide at 5 to 10% without issue: 15% is a good graduate step.\u003c\/p\u003e\n\u003ch4\u003eWill it cause flushing?\u003c\/h4\u003e\n\u003cp\u003eSome users experience brief flushing on initial use. This typically resolves within 2 to 4 weeks of consistent use.\u003c\/p\u003e\n\u003ch4\u003eCan I use it with retinol or vitamin C?\u003c\/h4\u003e\n\u003cp\u003eYes. The old \"niacinamide cancels vitamin C\" myth has been debunked. Layer them in the same routine without issue. With retinol, apply retinol first, let absorb, then niacinamide.\u003c\/p\u003e\n\u003ch4\u003eResults timeline?\u003c\/h4\u003e\n\u003cp\u003eSebum control: 1 to 2 weeks. Pore appearance: 3 to 4 weeks. Pigmentation fading: 6 to 10 weeks. Barrier strengthening: ongoing.\u003c\/p\u003e\n\u003ch4\u003eCan sensitive skin use this?\u003c\/h4\u003e\n\u003cp\u003eNot as a first niacinamide. Sensitive users should start at COSRX Niacinamide 5% (if it exists) or belif's gentler brightening option.\u003c\/p\u003e\n\u003ch3\u003eRelated Products\u003c\/h3\u003e\n\u003cp\u003ePair with the COSRX collection, especially the COSRX Snail Mucin Essence as a soothing layer. Browse Korean serums and best Korean products for oily skin.\u003c\/p\u003e\n","brand":"mirai-skin","offers":[{"title":"Default Title","offer_id":51741072392480,"sku":"51816160985460","price":12.48,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1004\/8333\/4432\/files\/915104cfd86b8989cfbfec91118f7b8c.webp?v=1779694392","url":"https:\/\/usmirai-skin.com\/products\/cosrx-the-niacinamide-15-serum-20ml-mirai-skin-cosrx-the-niacinamide-15-serum-20ml","provider":"usmirai-skin.com","version":"1.0","type":"link"}