The ink gel made from the Genipa Americana fruit,ink (Jagua Gel) is first applied to the skin with an applicator needle. This applicator does not penetrate the skin in any way. As the gel dries on the skin (minimum 2 hour), and removed with running soapy water, it leaves a yellowish to nearly invisible stain on the skin. This stain remains on the first layers of the skin, then it seeps deeper into the layer with passing time.
Oxygen and heat play an important role in this process. Heat allows the stain to penetrate deeper, and oxygen allows the stain to darken. Knowing that this is the outermost layer of the skin, skin cells are constantly dying off and renewing. As the skin cells die and shed off, the Jagua particles fall off with them.