I was researching oil pulling for someone and could not find any empirical data on it.
However, I found one anecdotal story from someone in a forum who said they started oil pulling and their hair went back to their natural color... from grey!
Well, I immediately started using it :-)
I am happy to report that I also lost my grey, to a point. I was about 15% and was about 5% when I finished. Had I kept it up, maybe it would have continued.
In fact, maybe I'll try it again, now that I'm more settled.
Many people use a vegetable type oil because it's cheap. But I also researched the benefits of coconut oil -which had quite a bit of peer-reviewed studies- so I had plenty of it in the house. You definitely get used to the taste. I actually miss it... just the taste.