Thank you for that information. i do not want any dangerous chemicals in my system. I recently started to try to treat myself naturally for depression. I started on a couple of L-tryptophan doses from Dr. Hulda Clark 's vitamins so as i a know that the vitamins are pure. I thought i was feeling better but got really sick..when i started taking the B6 that i thought was necessary to combine the L-tryptophan with. Maybe thats why i felt so ill. Can anyone let me know what dosage of Ltryptophan to take and what to take with it? Also, is there any one brand that is supposed to be the best? thanks for all your help and wonderful information.