Few harbingers of old age are clearer than the sight of gray hair. As we grow older, black, brown, blonde or red strands lose their youthful hue. Although this may seem like a permanent change, new research reveals that the graying process can be undone—at least temporarily. via Technology and News Today https://www.scientificamerican.com/article/gray-hair-can-return-to-its-original-color-mdash-and-stress-is-involved-of-course/