It is important to try and get quality controlled capsules too so that they have enough of each active ingredient in each capsule. Something that can go wrong with St John's Wort (I've heard) is that there are some brands that don't have consistency in active ingredient across tablets and / or they contain less of the active ingredient than they say they do.

I've heard the laws are stricter in Canada than the US regarding quality control on these kinds of non prescription products. Might be worth looking into that online too.

And looking at how hefty of a dosage you should be looking at taking (sometimes people are surprised at how much is reccomended to take for people who are really rather depressed rather than people who are just feeling a 'little flat')