KINS Serum

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KINS SERUM harnesses moisture-enriching ingredients which have been cultivated by beneficial bacteria, and revitalizes the skin with fermented extracts to effectively seal in essential hydration.

KINS BOOSTER and KINS SERUM, two innovative beauty products resulting from an extensive battery of nearly 10,000 tests, represent a distinctive skincare approach that encompasses everything you need.

Sharing a common goal with the booster, KINS prioritizes maintaining skin health by adhering to a mildly acidic skincare regimen. Enriched with six varieties of bacteria-derived components and two types of human ceramide, they cocoon the skin in a moisture-rich embrace. The formula is further enriched with 3-O-ethyl ascorbic acid, a highly permeable vitamin C derivative, and Saccharomyces cerevisiae extract, designed to combat glycation, alongside other skin-beneficial ingredients.

Key Ingredients:

Three Fermentation Extracts: 

KINS incorporates the Lactobacillus acidophilus / Soymilk Fermentation Liquid into all its skincare products, along with rice fermentation liquid, Aspergillus / Soybean seed extract, and a medley of plant-based components that lovingly embrace the skin with essential moisture for radiant and healthy skin.

Saccharomyces cerevisiae Extract, derived from components broken down by yeast bacteria, is a hydrating and skin-nourishing ingredient rich in various amino acids, peptides, and vitamins.

Two distinct ceramides function as vital moisturizing elements naturally found in the skin, essential for preserving the skin's protective barrier against dryness and irritation. While various ceramide types exist, KINS opts for human ceramide, characterized by a structure closely mirroring our skin's own composition.

3-O-ethyl ascorbic acid (vitamin C derivative) increases collagen production and luminosity and provides antioxidant protection from free radical damage.

Fermented Aspergillus/soybean seed extract is rich in antioxidant properties which help moisturize skin, target hyper-pigmentation, and fade dark spots.

Does not contain parabens, ethanol, synthetic fragrance, or colorants

Recommended to use with KINS BOOSTER or BOOSTER MOIST

How to use: Use on a clean face immediately after booster. For those who do not use the booster, please use before toner. Use one drop in the morning and one drop at night for best results.

Ingredients: Water, Lactobacillus acidophilus/Soybean milk fermentation liquid, Lemon fruit water, BG, Squalane, Diglycerin, Jojoba seed oil, Rice fermentation liquid, Rice nuka extract, Sake lees extract, Saccharomyces cerevisiae extract, Ceramide AP, Ceramide NP, 3-O-ethyl ascorbic acid, Caprylic acid glyceryl, Stearyl alcohol PEG-8 laurate, butyl alcohol, glucosyl hesperidin, Aspergillus/soybean seed extract fermentation extract solution, candlenut root extract, glyceryl stearate, polyglyceryl-2 stearate, dimethicone, PEG-60 hydrogenated castor oil, grapefruit seed extract, grapefruit seed extract, xanthan gum, allantoin, ethylhexylglycerin, sodium citrate, arginine, glycerin.

*Some ingredients are derived from soybeans. If you are allergic to soy, please consult your doctor to be sure.

Volume: 30ml

We ship internationally from our warehouse here in Tokyo. We use the services of third-party delivery service providers, namely, Japan Post (EMS) and Airmail, for shipping all the orders placed by our customers. View our entire policy here.

Every skin is different, therefore, no returns are accepted simply on the account that the product had an adverse reaction on your skin, or did not provide you any particular kind of results that you were expecting. However, you may initiate a return for the defective and damaged products purchased from the website within a period of7 (seven) days calculated from the order delivery date (“Return Period”). View our entire policy here.

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Unlike generic beauty retailers, Beauty Ninja carefully curates only the most advanced and luxurious Japanese skincare. Every product is tested and approved for its effectiveness.

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Yes! We source all products directly from Japanese brands, ensuring 100% authenticity.

In Japan, expiration dates are usually not printed on cosmetics unless required (e.g., food or medicated products). However, we keep small stocks and order directly from manufacturers to ensure you get the freshest products. Most items have a shelf life of 2–3 years when stored properly in a cool, dry place away from direct sunlight.

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Orders ship within 1–5 business days (we often order directly from manufacturers to ensure freshness). Once shipped, delivery takes 5–10 days, but times may vary due to customs or other delays.

  • Free for orders over $250 USD
  • Flat rate $15 USD for all other orders.

We ship to over 60 countries, including the USA, UK, Australia, Canada, and most of Europe and Asia. See our shipping page for the full list.

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