Worried you might be dehydrated? Need to monitor your glucose levels? In the future, you may be able to monitor these and other health conditions by checking the color of your tattoo. Researchers at Harvard Medical School and MIT’s Media Lab working on a project they’ve dubbed “Dermal Abyss” paired biosensitive inks with traditional tattoo artistry to take wearable technology to the next level.

Ali Yetisen, a postdoctoral fellow at Harvard Medical School, says biosensors incorporated directly on the skin could overcome some of the current drawbacks of wearable tech, such as short battery life or the need for wireless connectivity. “We wanted to go beyond what is available through wearables today,” he said in a story on Harvard’s official news site.

The tattoo inks change color based on the chemistry of the body’s interstitial fluid. One ink they developed changes from green to brown as glucose concentration increases. Another green ink researchers developed is viewable under blue light and grows more intense as sodium concentration rises, an indicator of dehydration. The researchers tattooed the inks onto segments of pig skin to test them.

Nan Jiang, another postdoctoral fellow at Harvard Medical, says the project was a proof of concept, and further refinements would be needed to ensure the ink doesn’t fade or spread into surrounding tissue. Once the kinks are worked out, the inks could be used in long-lasting tattoos for chronic conditions or temporary designs for short-term monitoring, Yetisen says. They could even be invisible, readable under certain types of light.

Jiang admits the project raises questions about ethical issues about whether people would be willing to have their health information displayed on their skin, but spurring such discussions was part of the point of the project. “The purpose of the work is to light the imagination of biotechnologists and stimulate public support for such efforts,” she says. “These questions of how technology impacts our lives must be considered as carefully as the design of the molecular sensors patients may someday carry embedded in their skin.”

This isn’t the first time technology has been infused into tattoos. Last year, researchers at MIT’s Media Lab created stylish metallic temporary tattoos that transform the wearer’s arm into a touchpad controller.

To learn more about the Dermal Abyss project, check out the video below.