I wouldn't go above 20mg of active Boron per day. I won't get into it again but check the beginning of this thread, after a little bit you'll see I went over proper labelling of the mineral and how to determine the amount. I can't personally speak for how all products, but I go over what it should look like on a proper label.
You probably don't need 20mg anyways. Tons of benefits at 3mg per day, some studies at 6mg, and some of the testosterone benefits at 10mg per day, which is probably what I'd take if I was after that.