On the fence on this one.
First, xipamide is not easily obtained. Surely the black market will produce anything if needed. Very unusual to find this drug anywhere, particularly to act as a diuretic, which makes sense to keep weight down for climbing. A few lbs could go a long way climbing.
Next, there are well known documented FDA cases where OTC supplement companies have spiked/tainted their "performance enhancing" or "male sexual performance" supplements with real pharmaceuticals.
One example is Palo Alto Labs. Look that up. Easy to find the info. Basically they had a male sexual performance natural enhancing supplement on the market. When analyzed, whoopss...they found Sildenafil (Viagra) crushed and added to their "natural formula" to better enhance male performance!
Yes, they were putting a pharmaceutical FDA regulated drug they obtained in generic form in their stuff they sold at the local health food store and online OTC.
So, Frank could have easily taken a weight loss/performance type OTC supplement, that had God only knows what put into it to help people lose weight, thinking their drug works and to keep buying it.
Of course, Frank should know exactly what he is taking, particularly a day later after the test the past several days regarding supplements...come on, who doesn't know that?
Food, well, that is another thing, it is sometimes hard for the average person to remember exactly what they ate the day before, or two days previous, unless they eat a very strict routine diet of the same things...then you should know exactly also.
The other side of this, it sure is suspicious and not the first time we've had somebody with trace WADA banned substances and claiming tainting of something they ingested.
I think that is the genius of this type of "doping." You can find some obscure drug that will provide a benefit for you, or try to mask/flush your body of other things, then when it is found, and since it is so rare to find it, just claim you must have been poisoned or ingested tainted supplements.
Worked pretty well for Contador. He lost his TDF title, and suspended a short time. But his own country gave him a pass. I'm sure he will be loved and heralded upon his return to racing later this year!
Good luck Frank. I see a short suspension coming out of this from UCI under a year likely.