I heard folic acid too. I started 15 years ago after hearing a study done on Nun’s.
I think I read of it in either a Swedish or Swiss study.
My dad has been taking it for over 25 years every day. He just turned 88 and is sharp as a tack.
Your mileage may vary.
I would suggest looking into folate as Metafolin, because this is the actual active form.
There’s not a good understanding of what happens to folic acid in the body. It’s not believed to be capable of being stored for long, but unconverted, it’s not known to be excreted, either.
If it’s like iron, it takes a different form, but this isn’t known for folic acid.