How Do Magnetic Eyelashes Work | Magnetic Lash Bash
Magnetic eyelashes with eyeliner work with the iron oxides in the magnetic eyeliner. The tiny magnets on the lash strip grab onto the iron oxides that are in the liner. This application type works best when the magnetic eyeliner is at least 80% dry. Wet magnetic eyeliner is not as effective. It's a simple explanation.
According to the EWG Skin Deep® | What is IRON OXIDES iron oxides are rated well and little cause for concern.
If you check the ingredients in all of the cosmetics in your closet you will find iron oxides in many of them.