It is a common hair loss myth that shaving your head or facial hair can make it grow back faster and thicker. The only thing the razor does is cut the eyebrow hair shafts at the same level as your skin. However, the follicles that produce them remain unaffected. This means their growth rate will remain the same as before.  So shaving your eyebrows is a safe way of removing them, as it does not damage your hair follicles the same way plucking them can. But it will not increase their growth speed.