What ingredients are in henna tattoo solution?

In a henna tattoo solution, there will be finely sieved henna powder, an acidic liquid to bring out the colour of the henna, and possibly a little oil. Usually, when making your own henna tattooing paste, the acidic liquid will be lemon juice or tea/coffee (no milk or sugar). The oil helps to create a smooth texture for application, however too much oil will prevent the colour from "sticking" to the skin. I usually use a teaspoon of sunflower oil in the mixture.

The tattooing solution should be mixed to the consistency of thick cream, then left to stand for 24 hours before using; this allows the lemon juice to really draw out the colour of the henna. You may need to add a little more liquid to the mixture before using it.

In commercially sold henna tattooing solutions, the ingredients are far more dubious than what goes into a home-made tattooing solution. Check the label before using them, buy the solution from a very reputable place, and google any ingredients that you do not recognise. Some people can have serious allergic reactions to a few of the more "dodgy" ingredients that are allowed in commercial henna tattooing solutions - particularly a substance called PPD, which makes the tattoos appear black. (In reality, henna is only ever a red/brown colour; never black).