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Serotonin is a hormone that regulates mood, memory, learning, appetite, sleep and muscle contraction. If there is not enough of the hormone available for nerve cells, you may feel depressed and anxious. Selective serotonin reuptake inhibitors, also known as SSRIs, are chemicals that inhibit the metabolism of serotonin, thereby increasing its availability to nerve cells. Some herbs act as natural serotonin reuptake inhibitors and may help relieve symptoms of depression and anxiety. Consult a medical professional before starting herbal therapy.

Herbal Actions

The hormone serotonin acts as a neurotransmitter, which is a chemical that delivers messages from one nerve cell to another. To do this, the chemical must jump across the space between nerve cells, called a synapse. After serotonin makes the jump from the first cell to the second cell, it may be reabsorbed by the first cell, thus ending its effect. This is known as reuptake. Herbs and drugs that inhibit reuptake leave more serotonin in the synapse to extend its availability and beneficial effects. Consult a knowledgeable practitioner for advice about dosage and preparation of these herbs.

St. John’s Wort

St. John’s wort, or Hypericum perforatum, is a perennial shrub originally from Europe and Asia but also found throughout North America. Traditional healers use the flowers to treat mild depression, anxiety and wounds. In their 2009 book, “Medicinal Plants of the World,” botanist Ben-Erik van Wyk and biologist Michael Wink note that the active ingredients in St. John’s wort that inhibit reuptake are hypericin and hyperforin. This herb may cause photosensitivity in high doses. It may elevate serotonin levels if combined with other antidepressants, so check with your doctor before using it with other drugs.


Sceletium, or Sceletium tortuosum, is a small succulent with yellow flowers that is native to South Africa. Traditional healers use the dried whole plant to treat anxiety, stress, tension and colic. Active ingredients include the alkaloids mesembrine, mesembrenone, mesembrenol and tortuosamine. A study published in the October 2008 issue of the “Journal of Ethnopharmacology” identified mesembrine as a potent serotonin reuptake inhibitor. Van Wyk and Wink note that the plant does not cause dependency even after years of constant use. Do not combine sceletium with other antidepressants.


Licorice, or Glycyrrhiza glabra, is a native Mediterranean plant and traditional remedy for coughs, ulcers, sunburn and skin disorders. Licorice is rich in flavonoids and saponins. A study published in the April 2003 issue of the “Journal of Molecular Neuroscience” found that several flavonoids, including glabrene, glabridin and 4'-OmeG, a derivative of glabridin, inhibit serotonin reuptake. These plant chemicals act like the hormone estrogen, which is also a serotonin reuptake inhibitor. The authors suggest that licorice flavonoids may benefit pre- and postmenopausal women with mild to moderate depression. Do not use licorice if you have hypertension or heart problems.