Boron dosage revisited

I have read that the dosage of boron in the form of borax is about 1/8 teaspoon to 1/4 teaspoon. However according to my calculations:

1/8 teaspoon = 0.625 ml
0.625 ml of borax = 0.625 x 1.73 (density of borax) = 1.08g of borax

1.08g of borax = 1.08 X 0.11 (percentage of boron in borax) = 0.12g of boron

And 0.12g of boron is 120mg of boron. And I have read that the daily intake should not exceed 18mg.

Unless my calculations are wrong, 1/8 teaspoon is still way higher than the recommended dosage.

Any thoughts? Tweet