You could try this powdered stuff, ive never ordered from them but they do seem pretty cheap, even for brand name stuff.
Anyone used their bulk powders?
http://www.bulknutrition.com/?products_id=2077
I bought a Poliquin podcast at the weekend(mass gain one), he mentions lowering cortisol serveral times, 2 tips being taking 1g of mg in split doses after 4pm and stretching before bed.
PS is meant to good for improving memory too of course.