St. John's Wort supplement: emotional balance & mood

St John's Wort Extract is a supplement containing St John’s Wort, aimed at treating mood disorders (1). It’s a natural anti-depressant approved by the WHO for combatting inner restlessness and anxiety, and which helps to alleviate sleep problems. Its content of hypericin, the plant’s main active principle, has been standardised to enhance its efficacy.

What exactly is St John’s Wort?

St John’s Wort is a plant rich in phenolic compounds (caffeic and chlorogenic acids, tannin, rutin, hyperoside, quercetol (2)). However, its effects on mood are generally attributed to naphtodianthrones, particularly hypericin, a pigment responsible for the colour of the oil released from the blackish dot-like glands on the plant’s flowers and leaves.

How does St John’s Wort affect mood?

St John’s Wort’s mechanism of action is not yet fully understood. We know that its bioactive constituents include flavonoids, procyanidins, hyperforin and hypericin, and that it works via a different mechanism to that of normal anti-depressants.

The serotonergic, noradrenergic and dopaminergic systems and gamma-aminobutyric acid (GABA) pathways, may all be involved in the action of St John’s Wort. It has been shown in studies to inhibit synaptic reuptake of serotonin, dopamine and noradrenaline (3), as well as to have a significant affinity for adenosine, GABA and glutamate receptors. There seems to be a synergistic effect between hyperforin, hypericin (4) and various flavonoids (5) in the reuptake of neurotransmitters and adrenergic and serotonergic receptor density (6).

St John’s Wort may also be involved in regulating genes that control the function of the hypothalamic-pituitary axis.

What are the effects of St John’s Wort? And how much should you take?

Researchers have shown St John’s Wort to be as effective at ‘chasing away the blues’ naturally as anti-depressants (7-8) in a meta-analysis of 29 clinical trials (involving close to 6000 subjects) (9). Participants in these trials received between 500mg and 1200mg of St John’s Wort containing 0.2% hypericin, for between 4 and 8 weeks (10) (that’s 2-3 capsules of St John's Wort Extract).

The hypericin in St John’s Wort also has sedative properties (11). It may help to reduce the physical symptoms of withdrawal and induce vasodilatory effects.

Its use for reducing anxiety and depression (resulting from nervous fatigue, overwork, stress, etc.) is recognised by ESCOP, Commission E and the WHO.