St. John’s wort, a herb, gained prominence due to its uses in many conditions. It is most well known for its therapeutic effect on mental health conditions, notably mild to moderate depression.

St John’s wort is a flowering, plant species also known by the botanical name Hypericum perforatum. It is also called by other names such as Tipton’s weed, Chase-devil, and Klamath weed.

In some places, the hypericum species as a whole is commonly referred to as St John’s wort and hypericum perforatum is then referred to as the Common St John’s wort for the purpose of differentiation. It is commonly misspelled as St John’s wart.

You find it grown in North America, Europe, Turkey, Russia, India, and China. This is a plant with yellow flowers, the concentrated extract of which is available as St John’s wort tea, tablets, capsules, liquid and topical preparations such as St John’s oil. These products are available over the counter at a health food store and do not need a prescription.

St. John’s wort is mostly taken in liquid or capsule form. Its dried form may also be used as a tea. The most common dose used in studies has been 300 mg, three times a day as a standardized extract.

In the United States, Saint John’s wort is considered as a weed and is sold as a dietary supplement. It has been used in medicine in many countries for thousands of years mainly as an herbal remedy for mental health conditions such as depression. It is one of the most commonly used herbs for depression in Europe.

We know quite a bit about its short-term effects but little about the effects of taking it long-term.

Why the name St John’s Wort?

Why St John? This plant is named thus because of its traditional flowering and harvesting on St. John’s day which is June 24th. Wort is an old English name for herb or plant.

Why hypericum? This plant is traditionally hung over religious idols on St John’s day to ward off evil. Hyper in Greek means above and eikon means a religious work of art, usually a painting.

Perforatum refers to the translucent dots, which are oil glands in the leaves and look like perforations when held against the light.

Uses and Benefits of St John’s Wort 

Though this is an over the counter preparation, you should always consult your doctor before taking this preparation. St John’s wort is used for the following conditions.

1. Mild to moderate depressive disorder

In medicine, St John’s wort is most commonly used for depression. Data suggests that it is more effective than a placebo and it is considered equally effective as the tricyclic antidepressants in treating mild to moderate depression with fewer side effects.

Comparisons with other antidepressants such as SSRIs are still inconclusive. Its use in severe depression has not proved effective.

2. St John’s wort oil

Topical preparations of St John’s wort such as St John’s wort oil are used in wounds and first degree burns, skin cuts and scratches and muscle strain.

3. Other Uses

Recent investigations suggest that hyperforin, which is a major constituent of Hypericum perforatum L. (Saint John’s wort) has an anti-inflammatory and antibacterial effect. This widens its use in other conditions.

These conditions include:

  • Somatoform disorders. This is a psychiatric or mental disorder which is characterized by physical symptoms, which cannot be explained.
  • Anxiety
  • Subacute Atopic dermatitis
  • Depression in children
  • Nerve pain
  • Symptoms of perimenopause
  • Alcoholism
  • As an antibacterial against gram-negative bacteria
  • In premenstrual syndrome
  • HIV/AIDS.

Dosage of St John’s Wort

St John’s wort has been recommended in the following dosage:

For adults

It has been suggested that at least 900 mg to 1800 mg of the extract be taken daily by mouth to get a therapeutic effect. It is taken in two to three doses daily for several weeks. You can also take it twice a day with tea by adding one to two teaspoons of the dried herb.

Dosage for children

150 mg to 1800 mgs daily by mouth in divided doses.

Mechanism of action

Hyperforin is the main active ingredient responsible for the action of this herb.

Initial biochemical studies, which were done with St John’s wort suggested that this preparation inhibits the uptake of the neurotransmitters, serotonin, dopamine, and norepinephrine by the synapses.

Synapses are connections or junctions between nerve cells.  This action is attributed to hypericin, a hyperforin derivative, and flavonoids, substances which are present in the extract of this herb.

In-vivo studies indicate that St John’s wort brings about the up-regulation of serotonin  5-HT(2) in the brain, which results in the required changes in the concentration of the neurotransmitters in the brain, and which have a direct bearing on depression.

The active component of St. John’s wort, hyperforin, decreases the uptake of the neurotransmitters, thereby increasing their efficacy.

The main neurotransmitters affected are norepinephrine,  dopamine, L-glutamate, gamma-aminobutyric acid (GABA), and serotonin.

About the safety of St. John’s wort for depression

Due to drug interaction, St. John’s wort limits the effectiveness of many prescription medicines.

Combining St. John’s wort with the use of certain antidepressants can lead to a dangerous increase in your body’s levels of serotonin, a chemical produced by nerve cells. This can be life-threatening.

Symptoms of raised serotonin levels can set in within minutes to hours and can include agitation, diarrhea, a rapid heartbeat, increase in blood pressure, hallucinations, and raised body temperature, among others.

Research supports the safe use of St. John’s wort for a short duration (less than 3 months) in the recommended doses and where the individual is not taking any other prescription medication.

Drug interactions

St John’s Wort can interact and weaken the medical efficacy of many medicines. These include:

  • Antidepressants
  • Birth control  pills
  • Cyclosporine used to prevent the body from rejecting transplanted   organs
  • Digoxin, a heart  medication
  • Oxycodone, a pain medicine
  • Some HIV drugs, including indinavir
  • Some cancer medications, including irinotecan
  • Blood thinners including Warfarin

St. Johns Wort Side Effects

Though it is a herb, side effects of St Johns wort do exist. However, some people may not experience any side effects.

For the first three months of taking St John’s wort, usually, no side effects manifest. It is later that they begin to show.

However, though this is an over the counter preparation, always consult your doctor before starting its use. The U.S. Food and Drug Administration has not approved St. John’s wort for medical use. Commonly known side effects include:

  • Gastrointestinal upsets leading to diarrhea
  • Allergic skin reactions such as skin rash and itching
  • Fatigue and drowsiness
  • Insomnia
  • Restlessness and anxiety and panic attacks
  • A headache
  • Dry mouth
  • Sexual dysfunction (including erectile dysfunction or impotence)
  • Rarely photosensitivity or sensitivity to sunlight
  • Feelings of elation alternation with a depressed mood
  • High blood pressure
  • Palpitations
  • There are reports that St John’s wort may cause mental tendencies such as suicidal or homicidal inclinations.

Precautions and Contraindications with St John’s wort (SJW)

  • The efficacy of St John’s wort is not consistent in treating depression. Do not replace the regular medication you are taking and do not self-medicate with this herb.
  • St John’s wort and Pregnancy. You should exercise caution when taking this herb if you are pregnant or breastfeeding your baby as there is no scientific evidence to support its safe use in these conditions.
  • If you develop an allergic reaction after its use, stop taking this herbal preparation.
  • Women who use the contraceptive implant, Implanon, should not use St John’s wort as it reduces the efficacy of the contraceptive.
  • It is contraindicated in children and elderly people.
  • People who have a compromised or a lowered immune system should not use this herb.
  • Research indicates that St John’s wort reduces the effectiveness of birth control pills and certain heart medications. People on these medications should consult the doctor before starting therapy with this herb.
  • If you are taking antidepressants, do not take St John’s wort. Similarly avoid SJW, if you have taken SSRIs within the last 15 days.

Where can you buy St John’s wort?

  • As mentioned above, St John’s wort is an OTC (over the counter) product, and available without a prescription at most pharmacies and health food centers.
  • You should look for a St John’s wort product, which has been standardized for hyperforin, its active ingredient.