- Alcohol makes skin more permeable. This means that when alcohol is used in the ink or to disinfect the skin's surface, it allows more chemicals to cross into the bloodstream than ordinarily would.
- Another interesting factoid concerning alcohol is that it is known as a 'promoter'. In biomedical parlance, this means alcohol works synergistically with mutagens, teratogens, and carcinogens to make them more likely to cause harm than they would by themselves. If any hazardous substances are present in the ink, alcohol helps them into the body and then increases the chance that they may cause mutation or disease, not just at the site of the tattoo, but throughout the body.
- Medical-grade chemicals are intended for medical uses, so any impurities within them should be relatively safe. However, the trace amounts of contaminants in high purity chemicals from a chemical supply house may be extremely toxic substances! An example: distilled water that isn't intended for drinking, while technically pretty pure, can have highly toxic organic chemicals as contaminants.
- The person who mixes the ink needs to understand proper sterilization techniques. This includes knowing how to perform heat-sterilization and cold-sterilization and understanding the sterilization needs of different materials. Dry or mixed pigments should never be heat sterilized, since the heat can cause chemical changes in the pigment molecules, sometimes producing toxic substances.
Having said all of this, I still think ethyl alcohol, in the form of vodka, is the safest carrier for the pigments. Propylene glycol and glycerine do a great job of keeping the pigment in solution. Medical grade propylene glycol and glycerine are often available at pharmacies, feed supply stores, and stores that carry supplies for soap making or herbal medicine preparation. You can use this article to scare hypochondriacs away from tattooing or to prepare yourself to ask the right questions of a tattoo professional to ensure the safest tattooing, or as an introduction to preparing your own tattoo ink.