I don't think they are standardized but I got cilantro tablets from my dentist's office. It might be the closest thing to a consistent dosage but the price is extremely steep. $179 for 120 tablets.

http://micint.com/category.php?cid=187
http://media.photobucket.com/image/mic%20cilantro/wakeflip1/MiCCilantro.jpg?o=1

My question is how come they can't come up with an active ingredient or half life for cilantro?

I agree that high dose iodine definitely helps with mercury detox. In what way I don't know but I received great benefits from taking it and I believe mercury is at the root of my health challenges. We know that it flushes out the harmful halogens like fluoride, chlorine and bromides but I think it helps with metals too. Iodine killing candida is a good possibility. I have heard that before.