Notre revue de presse de la semaine passée : Du 5 au 9 avril 2021
Ready to get a tattoo?
Nowadays, more and more people are interested in getting tattoos for different reasons: for attention, self-expression, spiritual or religious reasons, as a reminder of a family member, etc. But how many of them are interested in the composition of tattoo inks and what they can do to their health and their skin? According to a recent report by the Swiss Federal Office of Public Health, more than 50% of color tattoo inks (based on 206 color tattoo samples) do not conform to regulatory requirements.
Composition of Tattoo Inks
Tattoo inks are composed of two main components: the carrier and the pigment. However, they often contain mysterious additives and impurities.
The carrier is the medium in which pigments are dissolved or suspended. It is composed of two ingredients: a binding agent and a solvent. The role of a binding agent is to hold together the pigment particles and to help distribute or suspend them in a liquid (solvent) that facilitates the injection of the ink into the skin. The most used binding agents in tattoo inks are polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and vinylpyrrolidone/vinylacetate (VP/VA) copolymer (see chemical structures in figure 1). These polymers are widely used in cosmetics and personal care products (hair or nail care). They are classified as “not expected to be potentially toxic or harmful”.
Most tattoo inks use water as a solvent, but some polyvalent alcohols can be added in order to regulate the drying properties (ethanol, isopropyl alcohol), increase the viscosity (glycerin) and dispensability (propylene glycol). Glycerin and propylene glycol, for instance, are also widely used in medicine, cosmetics and even electronic cigarettes. These alcohols serves also as disinfecting agents, however, their concentration should be limited because they can irritate the skin.
Figure 1: Chemical structures of some binding agents used in tattoo inks
Pigments are responsible for the colors of tattoo inks. As the tattoos are supposed to be lasting or permanent, they are in general insoluble in a water-based medium, and should not be biodegradable after application. The pigments are classified into two main categories: mineral pigment (usually metal oxides or salts) and organic pigments (synthetic chemical substances such as azo dyes, some pigments contain both organic and metallic components (examples are shown in figure 2). There are a great deal of pigments available in the market, and some are officially approved. However, many are in fact not approved for skin contact at all. A list of prohibited pigments as well as limited concentration of some heavy metals in colors tattoo inks can be found on the Swiss Federal Office of Public Health’s website.
These pigments have been banned for a good reason: they are usually toxic, carcinogenic or allergenic. For example, the basic Red 9 (pararosaniline) is known to be carcinogenic and flammable.
Figure 2: Chemical structures of some pigments used in tattoo inks
Additives and impurities
Pigments can also contain toxic impurities depending on the manufacturing/synthesis process used to make them. Heavy metals like tin (Sn), cadmium (Cd), lead (Pb) or even arsenic (As) can be found in mineral pigments. The contamination with heavy metals is much lower in organic pigment compared to mineral pigments, but they might contain some very toxic compounds such as nitrosamines, primary aromatic amines or polycyclic aromatic hydrocarbons. These three types of impurities are known to be carcinogenic and in the long term, could cause skin cancer. This is one of the reasons why the regulation also includes standards for the purity of pigments used. Unfortunately, this information is rarely communicated by producers. Moreover, the additives used in tattoo inks are usually not declared. These additives or preservatives are used by producers in order to stabilize tattoo inks against UV degradation or bacterial contamination. According to a study by the Swiss Federal Office of Public Health, 14% of the samples analyzed containing unauthorized technical preservatives such as phenol, octylisothiazolinone or benzisothiazolinone.
It is, however, important to point out that these considerations on the toxicity of tattoo ink is based on the known toxicity of individual compounds. The tattooing process has its own particularities, and the effects of these dangerous chemicals injected in the epidermis are not yet well understood.
How to get a safe tattoo
Since the tattoo ink market is quite complicated, the producers are not required to reveal all of the ingredients in their inks. To further complicate things, the regulations are different from one country to another, making it hard for customers to know which ink is safe and which is not. Tattoo professionals are indeed responsible for the safety of their inks. They must have a basic knowledge about tattoo ink regulations, as well as some general rules when purchasing inks, and should regularly control their products to make sure they conform to industry standards and laws. According to the Swiss Federal Office of Public Health, they are advised to require from their suppliers a written confirmation that their products meet Swiss legal regulations. They should also ask the manufacturers for the Material Safety Data Sheets (MSDS) of each pigment or carrier, as well as analyses, certificates or other documents proving their products do not contain prohibited chemicals. Furthermore, it is highly recommended to purchase inks from suppliers with a solid reputation, and avoid any lesser known suppliers or those who could be risky.
Before “getting inked”, ask your tattoo professional for health and safety information on the pigments and carriers to be used in your tattoo. Take a skin test with the inks (in order to avoid an allergic reaction). And of course, choose a professional with high hygiene standards (single use needles, sterilization equipment, clean and well ventilated environment).
Tattooed skin and health by J. Serup,N. Kluger,W. Bäumler (Current problems in dermatology, Vol.48)