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Bite Star
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Cybersigil Forearm
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The science
KoreInk is not a sticker, and it is not paint sitting on top of your skin. It is a plant-derived ink that reacts with the outermost layer of your skin, develops over about a day, and fades as that layer renews itself.
The short version: genipin, a compound from the Genipa americana fruit, bonds with amino acids in the top layer of skin and, with oxygen, turns a deep blue-black.
01
Genipin comes from the unripe fruit of Genipa americana, also called jagua, a tree native to Central and South America. People there have used the juice as a body dye for generations.
On its own, genipin is nearly colorless. The color only appears once it reacts, which is why a fresh application can look pale at first.
02
The top layer of your skin is rich in keratin and other proteins that contain primary amines. Genipin reacts with those amines and links together into a stable blue-black pigment. The reaction needs oxygen, so the color deepens gradually instead of appearing all at once.
The ink transfers to clean, dry skin and starts to bind.
Binding window. The design is fragile, so keep it dry and untouched.
The color develops and darkens as it reacts with oxygen.
Natural wear and fade as skin renews. Total life is about 10 to 14 days.
03
The pigment stays in the outermost layer of skin, a fraction of a millimeter deep. A needle tattoo places ink in the dermis below it, which is why that one is permanent. Because KoreInk lives in the layer your body constantly sheds and replaces, it leaves on its own.
| Needle tattoo | Sticker-style temporary | KoreInk | |
|---|---|---|---|
| Where the color sits | Dermis, deep in the skin | On top of the skin | Outermost skin layer |
| How it is made | Needle and pigment | Printed film | Plant-derived ink that reacts with skin |
| How it develops | Visible right away | Visible right away | Builds over 12 to 48 hours |
| How long it lasts | Permanent | A few days | About 10 to 14 days |
04
Genipin has a long history in food coloring and in research. Allergic reactions to it are rare but documented. Our ink is vegan and print-tested, and we still recommend a patch test: apply a small design to your inner forearm and watch it for 48 to 72 hours.
Talk to a doctor first if you have very sensitive skin, eczema or dermatitis, you are pregnant or nursing, or you are buying for a child.
This is not black henna. Black henna is a different product that can contain PPD, which causes serious reactions.
05
The color has not developed yet. It needs hours and oxygen to deepen.
The first hours are when the ink is binding. Water and rubbing early can interrupt that.
Skin there renews faster and rubs against things more, so the top layer turns over sooner.
Moisturize the skin around it, skip scrubs, and avoid long hot soaks.
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