well i have both...i got tianeptine (in germany tianeurax) prescriped by my doc, and the sodium powder from the above mentioned vendor.
for me i can say that there was everything fine with the powder....the pills are too low dosed. maybe you got bad luck with your vendor :(
regards
oh it could be because lots of websites sell those powders, who can you trust? i checked at least 5 or so before i made decision to buy from a place i brought other stuff a while ago so i thought it could be fine. but, i might try your vendor. also to ask, how low dosed were the pills? i didnt know they were made in germany.