johnt, bottom line, when your're OFF the measurement that is most important is how much L-DOPA is crossing the BBB, not how much is in the blood. The fact that you are OFF tells you that it's not enough. You've eaten more than enough protein to overwhelm the active transport system that moves the L-DOPA and all other similar amino acids across the BBB. It's pretty clear that 15grams of protein is 100x the amount of amino acids that is in 150mg of C/L - admittedly not all AA's in protein use the same transport system that moves L-DOPA across the BBB but it's enough AA's to prevent much L-DOPA from crossing the BBB, so i guess it take 2hrs for your body to move the AA's out of your blood into cells? so instead of getting into the brain, l-dopa is blocked from crossing the BBB and as it circulates thru the body more and more of it is destroyed so none gets into the brain. so i have to assume apomorphine uses a different transport system into the brain than l-dopa uses otherwise it isn't going to help when you eat too much protein. my point is that you can have a very high L-DOPA blood concentration and be OFF, in the real world you have to also measure total AA's. of course eating protein only becomes a major problem when you are advanced enough that you are producing very little of your own brain dopamine, i.e., past the 5 year "honeymoon" phase. isn't it just slightly amazing that after 40 or more years since c/l came on the market we are still discussing such basic problems? there should have been a "cure" by now.