Almost certainly placebo - kratom doses being measured in 10's of grams for plain leaf, you'd need a joint the size of a baseball bat to feel anything, if mityragine was smokeable to begin with. That doesn't stop rip-off artists marketing kratom joints, but they taste unpleasant and have no effect at all. The big drawback with kratom is that the most effective and reliable means of getting its full flavour is to eat a quite large dose of simple powdered leaf rather than over-hyped or spiked extracts, and with any kind of tolerance, the doses can get ridiculous (30gs +, even in gelcaps, doesn't go down well). If you have an opiate tolerance, kratom's only really useful in withdrawal.
Anyway, cap it up - tea's foul and no more effective. The stuff does taste pretty much like dirt, and isn't entirely water-soluble, so you end up chugging wet and vile powder. Best on an empty stomach, nausea may result, goes very well with a smoke.
