The Uses, Benefits, and Dangers of St John's Wort

Updated on October 25, 2016
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Mohan is a physician with over 20 years experience in family medicine. He is a Fellow of the Royal College of GPs, London.

Why St John's Wort?

St John's Wort has been used for centuries as a health aid in treating various maladies. Its popularity as a cure for Depressive ailments has led to an explosion of supplements containing varying doses of St John's Wort in the market, freely available for anyone to buy and take. Such unregulated intake and anecdotal evidence can help—as well as hinder.

Like many other herbal remedies, St John's Wort falls under the category of 'supplement,' its production and supply can therefore be largely unregulated. It does not need approval by the FDA or other health protection agencies and can be sold (and consumed) freely.

It is vital to sift the real evidence from exaggerated claims, understands its place in the treatment of Depression, and truly comprehend the interactions it may have with other prescribed medication.

John the Baptist
John the Baptist
Translucent glandular tissue on the leaves of Hypericum Perforatum
Translucent glandular tissue on the leaves of Hypericum Perforatum

Have you ever taken St John's Wort ?

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Hypericum Perforatum

St John's Wort is wild plant that belongs to the genus Hypericum. It was used medicinally in ancient Greece. The name St John's Wort, or St John's plant, is said to derive from the fact that it flowers and can be traditionally harvested on the 24th of June, which is St John's Day.

Others also say that the name the plant is attributed to St John due to the crimson/purple fluid that escapes when the flowering bud or the seed pod are crushed. The arrangement of the bright yellow petals resembles a halo and the reddish purple fluid is said to resemble the dripping blood. The ancient Christians must have named the plant after their martyr.

St John was beheaded by the order of King Herod, after a vengeful request by his stepdaughter Salome, a common Christian motif in art.

From ancient times, the plant was attributed to having magical properties in warding of evil spirits, and a sprig was hung over religious icons. (Greek Hyper - over; eikon - image/spirit.) Hence the name Hypericum.

The yellow-green leaves of St John's Wort contain translucent glandular tissue when held up against the light. This makes it look perforated, giving the species name Hypericum perforatum.

There are other species of Hypericum including Hypericum calcynium and Hypericum dubium. The latter's leaves do not show the perforations. The plant itself is a perennial weed common to Europe and Asia; it has now spread worldwide across China, India, Canada, and USA. It is also commercially grown in many areas.

Incidentally, it is listed as a toxic weed in over twenty countries. A widespread invasion of St John's Wort in grazing pastures can lead to toxic effects in livestock.

The plant has been attributed with magical properties in warding of evil spirits. A sprig was often hung over religious icons. Hyper = over; eikon = image/spirit. Hence the name Hypericum.

Varieties of St John's Wort ( Hypericum)
Varieties of St John's Wort ( Hypericum)

Like other herbs, St John's Wort is chock-full of naturally occurring chemical compounds. The vast array of them come under the umbrella term naphthodianthrones. The three major compounds are Hypericin, Pseudohypericin and Hyperflorin. The concentration of these compounds depends on the source geography, time of harvest, and the part of the plant used in extraction.

In addition to these three, the plant also contains various flavonoids, oligometric procyanides, and phenolic acids. The table below summarises the various chemicals contained in St John's Wort.

Chemical Constituents of St John's Wort

Group
Compounds
Naphthodianthrones
hypericin, pseudohypericin, protohypericin
Phloroglucinols
hyperforin, adhyperforin
Phenolic acid
caffeic acid, ferrulic acid
Alkanols
1-tetracosanol, 1-hexacosanol
Saturated fatty acids
isovaleric acid, myristic acid, palmitic acid, stearic acid etc.
Volatile Oils
nonane, 2-methyldecane, undecane, α-pinene, β-pinene etc.
Vitamins
carotenoids, choline, nicotinamide, nicotinic acid
Please note that this list is by no means exhaustive and doesn't reflect the individual concentration of these compounds.

The Historical Pharmacology of St John's Wort

Over the centuries there have been many anecdotal tales of the beneficial effects of St John's Wort. As with many herbal remedies that have travelled through the misty depths of time, it is hard to separate the tall claims from the true benefits.

There is no doubt the herb was held in high regard for its spiritual and medicinal uses. The ancient Greeks used it to treat melancholia, ulcers, digestive disorders, skin conditions, and sciatica.

In Chinese medicine, the herb has been held in high esteem in their Pharmacopoeia as Qian Cen Lou. It is used to treat fever, depression, nerve pain, and heavy menstrual bleeding.

The written accounts of the use of the herb start with Pliny the Elder. He notes that Hypericum 'promotes urine, checks diarrhoea, and helps the bladder'. It was used as a diuretic by ancient Physicians Galen and Dioscorides.

Paracelcus recommended picking the flowerbuds at sunrise and squeeze the buds to exude the crimson natural oil. The resultant preparation by mixing this crimson oil with olive oil is called 'Blood of the Christ'. This was used as a salve on open wounds, sprains, bruises, varicose veins, and bruises.

In other lore, the plant has been called 'herba demonis fuga'—the herb to chase away the demons. Perhaps this stems from the previous belief that mental illness was caused by evil spirits. There is even a gruesome rumour that the herb was stuffed into the mouths of 'witches' to force them to confess and expel the demons prior to burning them.

A common strand among all these anecdotes and the one enduring theme is that the herb helps to treat 'melancholia, anxiety, and illnesses of the imagination'.

In ancient lore, St John's Wort is also 'herba demonis fuga', the herb to chase away the demons. Perhaps this stems from the previous belief that mental illness was caused by evil spirits.

A 15th century herbal codex that lists 'ypericon' (St John's Wort) as a demon repellant!
A 15th century herbal codex that lists 'ypericon' (St John's Wort) as a demon repellant!

Depression and Anxiety

The considerable popularity of St John's Wort as a treatment for mild to moderate Depression does have some scientific basis. The compounds Hypericin and Hyperforin have been found to inhibit the re-uptake of serotonin and other neurotransmitters such as norepinephrine and dopamine. This effect is akin to the popular antidepressant class of drugs, the SSRIs (Serum Serotonin Re-uptake Inhibitors).

Using standardised doses and preparation there have been various studies that show that at best the supplement is as good as SSRI drugs—and at worst better than a placebo. There have been two major systematic reviews listed in Cochrane Database, and both conclude there are benefits to St John's Wort in treating mild to moderate depression. With the exception of its impact on other prescription drugs and some rare incidents, St John's wort is also relatively free of side effects.

The cautionary element is knowing how much of the active ingredients are contained in the supplements we use. Unlike prescription drugs where the stated dosage is strictly regulated, there are no direct controls on what constitutes a dosage. The daily values of Hypericin or Hyperforin have not been conclusively determined. The usual dosage of a 300 mg capsule is supposed to be 'standardised for 0.3%' of Hypericin. This leaves one to wonder what the remaining 99.7% is.

One of the shortcomings in research is that there have been no rigorous double-blind randomised trials.

The mechanism of action of St John's Wort supplements shows equal efficacy in serotonin and other neurotransmitter re-uptake, leading to beneficial effects in treating low mood.
The mechanism of action of St John's Wort supplements shows equal efficacy in serotonin and other neurotransmitter re-uptake, leading to beneficial effects in treating low mood.

Somatoform Disorders

There have been some trials that have shown that St John's wort has a beneficial effect on somatoform disorders. These are disorders where patients suffer from unexplained physical symptoms as a direct result of mental anxiety and mood disorders. The somatoform disorders are broadly classified as Conversion disorder, body dysmorphia, illness anxiety disorder, and chronic pain syndrome.

However, these are neither conclusive nor proven unequivocally.

Categories of somatoform disorders
Categories of somatoform disorders

Other Uses

Compounds in St John's Wort such as Hyperforin are being studied in various other related conditions. None of these are conclusive. The potential benefits in treating alcoholism are being looked into, as are the anti-inflammatory effects in treating muscle pain and bruises.

There are speculations about an antibacterial effect that could lead to use in wounds and inflammatory skin conditions. They all need more research, conclusive evidence, and potential assessment of benefits and risks.

In some cases, St John's Wort may cause photosensitive reactions
In some cases, St John's Wort may cause photosensitive reactions

Side Effects

Although generally well tolerated, St John's Wort does have rare side effects such as stomach upset, nausea, diarrhoea, confusion, fatigue, dizziness, restlessness, and headache.

In some cases there have been a photosensitive reaction on the skin causing an undue sensitivity to light and leading to sunburns and increased pigmentation.

In Schizophrenia, it can aggravate psychosis.

Interaction Wiith Prescribed Drugs

St John's Wort is proven to cause induction of the cytochrome P450 enzymes CYP3A4 and CYP1A2. Such induction will accelerate the action of these enzymes on the liver and cause increased metabolism of other drugs, reducing their efficiency. This may happen, for example, in someone on oral contraceptive pills. St John's Wort could reduce the efficiency and cause failure of the protection and unintended pregnancy.

Even more alarmingly, if taken with anti HIV medication, St John's Wort can cause the medicines to fail and increase viral load. Equally affected are anti-epileptic drugs such as sodium valproate, Asthma drugs such as theophylline, and anti-coagulants such as warfarin.

One of the more common occurrences is where a patient attempts to 'supplement' their dosage of prescribed antidepressants with St Johns Wort. This can lead to serious side effects due to serotonin syndrome.

St John's Wort can cause reduced efficacy of anticoagulants, immunosuppressants, and some sedatives. The following table contains a list of drugs that can be adversely interfered with by St John's Wort:

Interactions of St John's Wort

Drug
Interaction
Management if patients already on St John's Wort
Anticonvulsants (carbamazepine, phenobarbitone, phenytoin)
Reduced blood levels with risk of seizures.
Check anticonvulsant levels and stop SJW. Anticonvulsant levels may increase on stopping SJW. The dose of anticonvulsant may need adjusting.
Cyclosporin
Reduced blood levels with risk of transplant rejection.
Check cyclosporin blood levels and stop SJW. Cyclosporin levels may increase on stopping SJW. The dose of cyclosporin may need adjusting.
Digoxin
Reduced blood levels and loss of control of heart rhythm or heart failure.
Check digoxin levels and stop SJW. Digoxin levels may increase on stopping SJW. The dose of digoxin may need adjusting.
HIV protease inhibitors (indinavir, nelfinavir, ritonavir, saquinavir)
Reduced blood levels with possible loss of HIV suppression
Measure HIV RNA viral load and stop SJW.
HIV non-nucleoside reverse transcriptase inhibitors (efavirenz, nevirapine)
Reduced blood levels with possible loss of HIV suppression.
Measure HIV RNA viral load and stop SJW.
Oral contraceptives
Reduced blood levels with risk of unintended pregnancy and breakthrough bleeding.
Stop St John's Wort
SSRIs (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline)
Increased serotonergic effects with increased incidence of adverse reactions.
Stop St John's Wort.
Triptans (sumatriptan, naratriptan, rizatriptan, zolmitriptan)
Increased serotonergic effects with increased incidence of adverse reactions.
Stop St John's Wort
From Medicines Control Agency
Symptoms of Serotonin Syndrome
Symptoms of Serotonin Syndrome

Patients commonly attempt to 'supplement' their dosage of prescribed antidepressants with St Johns Wort. This combination can lead to serious side effects collectively called Serotonin Syndrome.

In Summary

There is no doubt that the enduring reputation of St John's Wort as a treatment for mild to moderate depression is backed up somewhat by a cross section of studies. In otherwise healthy individuals, provided they take a regulated dosage after consulting their Doctors and taken from a reputed source, there are benefits to be had. One may even venture to say as long as it is not mixed with other prescription drugs, there may be relatively fewer risks in trying St John's wort for somatisation and low moods linked to chronic pain.

However, it is unclear how much of these benefits are anecdotal and due to placebo effect.

There is no place for St John's Wort in severe depression, and there is no evidence on the other uses.

As always, it is best to consult a medical professional if you have other illnesses and are on prescription medication.

One wonders how patients who distrust pharmaceuticals will trust a 'herbalist' to dispense freely a largely unregulated supplement that may not always be from a reputed source. Bear in mind the need for reputable sources and relative bio-availability of the ingredients. These may vary from source to source. Natural doesn't always mean safe!

All is all, it may sound like science errs on the side of caution, but this is not to take away the enduring benefit of this wonder herb from time immemorial, that helps us chase the blues away.

One wonders how patients who distrust regulated prescription drugs freely trust a largely unregulated supplement. Bear in mind the need for reputable sources and accuracy in bio-availability of the ingredients. These may vary from source to source. Natural doesn't always mean safe!

The information expressed in this article has been gleaned from various sources and is meant to inform and educate.

However, I cannot emphasise enough the need for a consult with your own physician before taking therapeutic decisions. Medicine is complex. The same symptoms can mean different diseases in different people, and the mind will play games and the body will protest at will. So please exercise caution.

Be well!

St. John’s wort doth charm all witches away

If gathered at midnight on the saint’s holy day.

Any devils and witches have no power to harm

Those that gather the plant for a charm:

Rub the lintels and post with that red juicy flower

No thunder nor tempest will then have the power

To hurt or hinder your houses: and bind

Round your neck a charm of similar kind.

— An old poem

Questions & Answers

    © 2016 Mohan Kumar

    Comments

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      • profile image

        joanna 

        4 months ago

        I visited my dr this morning as i am having extreme hormonal fluctuatuons, i believe i have PMS and have had it a while. I think this because around every 3 months before my period i become extremely weepy for no reason and it is making me phone into work as i am unable to stop crying for hours on end. I am in my 30's, my skin has become spotty on my chin and jawline and i have black hairs growing on my face which is not very nice. After discussing my issues (whilst blubbering my eyes out) my dr rekons i am depressed and has recommended Prozac. I am a very natural person so i am reluctant to take such things. my friend has told me about at johns wort so this article has been very helpful. pros and cons are always good to know. would you recommend trying johns wort before even considering prescription drugs.

        thanks

      • profile image

        John000 

        23 months ago

        I have known many people who have used St. John's wort. The detail in your article helps me understand their use. Noting contraindications was helpful. I don't think many people are aware of them. Thanks.

      • Docmo profile imageAUTHOR

        Mohan Kumar 

        23 months ago from UK

        Good to be back, Martie. And glad to see you here too. I'm likely to be visiting South Africa in 2017. looking forward to it.

      • Docmo profile imageAUTHOR

        Mohan Kumar 

        23 months ago from UK

        MsDora, thanks for the visit and comment, much appreciated.

      • Docmo profile imageAUTHOR

        Mohan Kumar 

        23 months ago from UK

        Thank you Nell, Glad it is of interest.

      • MartieCoetser profile image

        Martie Coetser 

        23 months ago from South Africa

        Very interesting and useful article about St Johns Wort. Its interaction with prescribed drugs is quite alarming.

        Many years ago I gave it a try, but could not feel any relief from the depression I used to suffer. I once had a hypericum in my garden. It is actually a beautiful shrub.

        Good to see you back, Docmo!

      • MsDora profile image

        Dora Weithers 

        23 months ago from The Caribbean

        Have heard and read about the benefits of St. John's Wort. Thanks for these insightful details.

      • profile image

        Nell Rose 

        23 months ago

        Fascinating look at St. Johns Wort, I have used it in the past but can't remember what for! really interesting to see the pro's and con's of this plant.

      • Docmo profile imageAUTHOR

        Mohan Kumar 

        24 months ago from UK

        Thank you Peter, glad it has been instructional. Appreciate your visit and taking the time to comment.

      • Peter Dickinson profile image

        Peter Dickinson 

        24 months ago from South East Asia

        Fascinating...thank you. Having used it in the past it was interesting to learn more.

      • Docmo profile imageAUTHOR

        Mohan Kumar 

        24 months ago from UK

        Thank you , Faith for your visit and comment. I agree there is a perception among many that 'natural' means safe - this is not always the case as we know.

      • Faith Reaper profile image

        Faith Reaper 

        2 years ago from southern USA

        Excellent and comprehensive article here. I'm glad you included the warning as so many do believe that "natural" means okay without any side effects, but these "healthy" alternatives can certainly wipe out other important meds such as blood pressure, etc.

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