how much of a product must be in your urine for it to show up on a urine test. The specific product I am asking for is DMAA found in some pre workouts.

Also this is for a sports drug test by WADA, not a standard employment test, so they do look for DMAA.

for example:

half life is 12 hours, so you take 50mg, in 12 hours it will be 25mg. 24hours it will be 12.5mg. in 36 hours it will be 6.25mg.. etc.

at a certain point, this will get into the very small minute decimals. my question is, at what point does the product not show up on the test.

heres what it look like every 12 hours

1st half life - 25mg
2nd half life - 12.5mg
3rd half life - 6.25mg
4th half life - 3.125mg
5th half life - 1.5625mg
6th half life - 0.78125mg
7th half life - 0.390625mg
8th half life - 0.1953125mg.... etc. etc.