Glow-in-the-dark tattoo ink, also known as UV tattoo ink, is available, but the long-term side effects of the use of these inks for tattoos is unknown, according to TechnologyGuide. Despite the name, such tattoo inks glow only when exposed to UV light.
Clear glow-in-the-dark inks can be used to create tattoos that are almost invisible in regular light, or to enhance traditional color tattoos by adding embellishments that glow under UV light. UV tattoo inks are more expensive and take longer to apply than traditional tattoo inks. Though some tattoo artists claim that UV inks have FDA approval, the FDA's own website states that no inks, including glow-in-the-dark varieties, have been approved for use in tattoos.