I'm not a doctor and I take no responsibilty for rambling on...
You need to attack this problem from multiple positions at once, my friend. It's very important to try everything and not rely on any single method.
First, the best book I have seen on passing tests is called "Passing Drug Tests..." by Ken A. Biscranium. I just found it in Google Books so check it out. There are no guarantees, and overweight or sedentary people (couch potatoes) are way more prone to failing a cannabinoid test by urine - it will take longer to flush.
If it is a urine test there is hope. If it is a hair test, well...good luck.
It goes without saying, cease use of cannabis. It's very doable. Make the decision final.
Here are your weapons:
1) & 2) Cannabinoids (metabolites) are STORED in fat cells. If you are burning fat, you are releasing more cannabinoids from storage into your system. Generally, you cannot stop burning fat but you CAN change the rate at which you burn it. That's good news!
The first thing is you need solid exercise. This speeds up the metabolism, burns fat and helps flush your system. Lifting weights is not good enough for the avg. person, not even close. You have to burn fat quickly, which means intensity and duration. It's tough but it gets easier each time. Running, fast biking, all-day intense hikes in the hills. Be ready to lose a few pounds. If you don't push, you won't get there, but be careful and and take breaks. Being rested makes the whole program easier.
All along your urine should never be darker than straw, ever! Drink water. Save money.
ASAP, kill the intake of fatty foods. A little is okay but a diet of pizza, burgers, fries, fried food will screw you (again). You MUST burn off the fat that contains the cannabinoids. With that said, consider that the day before the test you should start LOADING on fat. Go eat a large pizza. You want to shut down the fat burning so as to minimize the cannabinoids getting released into your system. Overeat, slow your metabolism. Likewise, IMO, avoid exercise the ~day before. Be a lard ass and reward yourself for all the hard exercise and cannabis abstinence. Have a fat bowl of ice cream since you can't have a fat bowl of anything else! Pull peppermint vaporizor hits for inspiration (clean vaporizor).
3) Hit the dry sauna regularly (caution, ask yer Dr.). A steam room won't be as effective. You need to sweat heavily to help flush out toxins. We excrete cannabinoid metabolites in our urine, in our sweat, hair, and a great deal in poop. All of our nappy excretions serve to rid our bodies of these metabolites (by-products). The more excreting you do, the lower the concentration of the nasties.
4) Start dosing on a fiber supplement (Metamucel, wheat bran, Raisin Bran, Oatmeal etc.). Ramp up to make sure you don't get the runs. Eat lots of fruit, whole grains and veggies. Passing a test forces some good habits and it's a great motivator.
With certainty I've seen tests passed several times with 40 days abstinence, and fail with one week of water drinking and Test-Clean. Many folks get by with about 24 days. If you puff daily on the mega-ganji, then you need more time. If you are a weekend warrior then 3 weeks might be good. Again, it depends on you, how active and how much body fat.
5) Give up salt. Your taste will adjust and you won't miss it after a while. Unless you are vegan, you probably get plenty of salt already. Use GRANULATED garlic as a close, healthy second.
Extra Credit: Chili peppers help speed up the metabolism during the burn phase. Make your food spicy whenever you can.
Day Of: Fatty Breakfast, avoid sugar, plenty of water, a multi-vitamin or B-Complex to help color the urine and give it body, (too much makes fluorescent piss)...and I speculate that a cup of tea would be a good thing (caffeine is a diuretic and makes you dehydrate within). It might also be a good idea to take vitamin C, salt your breakfast and have a double strength protein shake ( the idea is to raise the specific gravity of your urine. Too much water makes it low, and you can 'fail' that way too).
The author of the book claims a couple days to success but he is a hardcore, thin, Lance Armstrong type eating every herb and supplement, pounding water all day, frequent saunas and weekly tests. IMO, these things are the most important. Use them all...AT YOUR OWN RISK.
Recap:
A) Stop cannabis use.
B) Burn Phase: BURN FAT - Regular exercise. Ramp up the intensity as best you can. Push 10% more.
G) Drink Water (pee and replace)
D) Sauna (sweat)
E) Fiber (poop)
F) Avoid salt.
Y) Chili peppers and spicy food (low fat).
R) LOAD FAT starting about a day before the test and QUIT EXERCISING a couple days before.
Tangent:
It's not a coincidence that passing a drug tests is way easier when there is what they call a "Healthy Lifestyle" in place...blah blah blah. Your body wants it that way and evolved that way...blah blah blah....Whoppers and Ford Trucks haven't been around too long when you think about it. 1,000 generations of walking, berries, greens and lean venison have resulted in YOU. It's your job to pass those same genes on for another 1,000 generations.
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