i smoke about once a day, but will have refrained from any smoking for about 2 weeks before the test. a couple days ago i gave the dillution method a trial run, but after taking the B 12 i waited and waited and urine never turned the "vitamin yellow". I checked the bottle and it did not say it was time release. So about 4-5 hours after the initial start to the dillution method i tried a home drug test and passed, although it was somewhat of a faint line, still negative. The next day i tested myself again about the 2nd or 3rd time i urinated for the day and failed. I hope this gives you guys a little more description into my situation. And either way thanks for the help so far, i will check back and keep you posted. Thanks again!