Here is my math;
We are talking about level teaspoons. My spoon fitted exactly 1 gram of borax, level that is.
1/8 of that is 125 mg borax, of which is 11 % boron = 13,75 mg of boron.

I have taken 1/4 for years (2-3 days a week) The workers in the borax mines inhale around 30 mg of boron daily via the borax dust. This was a study about it, no adverse effect found.

Jam1, You make too many assumptions.......

> 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

Theory and practice can differ... and it can get confusing.

For starters, there are too many assumptions.

#1) You say 'Borax'.
However, what kind of Borax?
Do you actually have Borax that is 99.99% pure?
Or, are you talking about the 20 Mule Team Borax?

#2) You say 'teaspoon'.
However, what kind of teaspoon?
Assuming you use a standard U.S. teaspoon,
Google says it is of 4.92892 ml, therefore 1/8 of is 0.616 ml.
However, your teaspoon may be smaller or larger than that.

#3) You say 'density'.
Assuming you work with pure Borax, indeed its density is 1.73 g/cm3. However, the 20 Mule Team Borax is different. According to Google, the label on the 20 Mule Team Borax says it contains Borax (Sodium Borate), Lactose, Sucrose, Sodium Tetraborate decahydrate (Sodium Borate). Therefore its density is probably less than the above-mentioned 1.73 g/cm3.

Further,

#4) If the only Boron-related product we can get is the 20 Mule Team Borax, then how do we know what percentage of it is 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?

Ideally you want to
1) Get Borax of 99.99% purity, as opposed to the 20 Mule Team Borax;

Ideally you want to
2) Use our own designated tsp, as opposed to the standard U.S. tsp;

Ideally you want to
3) Have access to a small scale that can weight our Borax, in milligrams;

Then, and only then,
4) Can we use the '0.11x' multiplier. And

Then, and only then,
5) Can we tell, if 1/8 tsp of Borax is too large, or too small, for us.

However, even if you accidentally overdose of Borax, nothing bad is going to happen to you.

Example: By mistake, a couple of months ago, of Borax, and for 10 full days or so, I took four times more than I should have. But - despite the usual fearmongering main stream media - nothing bad ever happened, and there were ZERO side effects.

I hope this will help!