Related

Type	How it works	Lasts
Decal transfer	Printed pigment on a paper backing, applied with water	1–5 days
Airbrush ink	Alcohol- or water-based pigment sprayed through a stencil	3–7 days
Semi-permanent "jagua-type" ink	Genipin from Genipa americana, staining the epidermis blue-black	1–2 weeks
Body-art pens and markers	Cosmetic pigment in a marker	Hours to days
"Black henna"	PPD — see below	Do not use

Genuine decal transfers sold as cosmetics use colour additives approved by FDA for cosmetic use, and are labelled as such. They are unremarkable products.

The most important paragraph on this page.

"Black henna" is not henna. Natural henna stains orange-brown and takes hours; black henna produces a black stain in under an hour because it contains para-phenylenediamine (PPD) — the oxidative dye used in Permanent Hair Dye — at concentrations far above anything permitted for hair, applied directly to skin.

PPD is not approved for direct application to the skin in the US or the EU. In hair dye it is restricted and carries a mandatory caution; on skin it is prohibited.

What it causes:

• Severe allergic contact dermatitis — blistering, weeping, and a raised reaction in the exact shape of the design.
• Permanent scarring and hypopigmentation, leaving the outline visible for years.
• Lifelong sensitisation. Once sensitised to PPD, a person can never safely use permanent hair dye again, and may react to related compounds in rubber, textile dyes and some black clothing.

FDA has issued repeated consumer warnings, and it is a recurring holiday-resort injury — most often in children.

The rule is simple: if it is black and it develops fast, do not have it done. Natural henna is orange-brown. See Henna.

• Buy cosmetics, not novelties. A full INCI ingredient list is required for retail cosmetics under 21 CFR 701.3; its absence is disqualifying.
• Named colour additives, not "colour".
• Patch test 24–48 hours before, especially on children.
• Not on broken skin, eczema or a rash.
• Not near the eyes or lips unless the product is approved for those areas.
• Glitter must be cosmetic-grade, not craft glitter.

Cosmetic in the US — FDA primary category (16) tattoo preparations, the category added by the MoCRA-era list — with no premarket approval, but with a real constraint: colour additives must be approved by FDA for the intended use, and certified colours must come from FDA-certified batches. A product using unapproved colours, or PPD on skin, is adulterated under the FD&C Act.

Under MoCRA, facilities register, products are listed, safety substantiation records must be held, and serious adverse events are reportable within 15 business days.

In the EU, PPD is restricted under Annex III to hair dye use only, permitted colorants come from the Annex IV closed positive list of 153 entries, and REACH restriction entry 75 governs tattoo and permanent make-up inks.

Decal transfers: two to three years, sealed and dry; they fail by drying out and cracking.

Liquid inks: 12–24 months after opening. Water-based versions depend on a preservative system; alcohol-based ones last longer. Discard anything separated, discoloured or smelling off, and never share an applicator between people at an event.

• Tattoo and Body Art — the shelf this sits on, and the rest of it.
• Cosmetics — what the label is legally allowed to say, and the full catalogue.
• The rest of Inks — Permanent Tattoo Ink · Permanent Makeup Pigment.
• Henna · Jagua — the plant dyes, and the black henna problem in full.
• Regulatory statements here follow the FDA and EU sources listed on Cosmetics, read 16 August 2026.