I had gray hair in my 30s. I was told that my father had gray hair even earlier.
I’m skeptical of the idea that Grecian Formula restores the original color. That would imply that the composition of gray hair differs depending on the person’s pre-gray color. A little googling reveals that Grecian Formula smells terrible, contains lead, and you’re only supposed to wash your hair once a week when you use it. Ugh.