St John’s Wort

One very common herb that most people have heard of is St Johns Wort, which is a herb that is very effective in treating mild to moderate depression (Morgan & Jorm, 2008). It inhibits the re-uptake of neurotransmitters dopamine, serotonin and noradrenaline in the brain, so in effect it is similar to some antidepressant medications, particularly Selective Serotonin Reuptake Inhibitors (SSRI’s).  It is thought that when levels of these neurotransmitters are low in the brain it leads to feelings of anxiety and depression.  In recent research St John’s Wort has been found to be just as effective as SSRI’s and tricyclic antidepressants in treating mild to moderate depression, and is superior to placebo (Melzer, Brignoli, Keck, Saller, 2010).

However St John’s Wort is not a safe herb to take without naturopathic supervision.  This is because it speeds up the detoxification pathways in the liver, specifically the cytochrome P45 pathway, which also speeds up the metabolism of many other medications.  What this means is it increases the liver’s ability to break down medications in the body, such as anticoagulants (warfarin), the oral contraceptive pill, some anticonvulsives, immune modulators (cyclosporine), barbiturates, cholesterol lowering medication (lipex) and the list goes on (Borrelli, Izzo, 2009). So if you are on any other medication, you should consult with your doctor or naturopath before taking St Johns Wort.  If you have any questions about this, please leave them in the comments section below so everyone can learn more about it.



Morgan AJ, Jorm AF.  Self-help interventions for depressive disorders and depressive symptoms: a systematic review. Annals of General Psychiatry. 2008 Aug 19;7:13

Melzer J, Brignoli R, Keck ME, Saller R. A hypericum extract in the treatment of depressive symptoms in outpatients: an open study. Forsch Komplementmed. 2010;17(1):7-14. Epub 2010 Feb 4

Borrelli F, Izzo AA. Herb-drug interactions with St John’s wort (Hypericum perforatum): an update on clinical observations. AAPS J. 2009 Dec;11(4):710-27. Epub 2009 Oct 27

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