Benefits (and Risks) of St. John’s Wort for Depression

Last updated November 15, 2023.
Edited and medically reviewed by Patrick Alban, DC. Written by Deane Alban.

St. John’s wort is a popular remedy for depression; however, it has many side effects and interactions. Get the latest facts and learn about alternatives.

It has a 2,000-year-old history as a natural remedy and was mentioned in the works of Hippocrates and Pliny.

Traditionally, it was used both externally and internally to treat conditions as diverse as insomnia, wounds, burns, snakebites, nervous disorders, melancholy, tumors, and intestinal parasites. 

Recent research suggests that St. John’s wort may be useful in treating numerous ailments, including ulcers, cancer, Alzheimer’s, Parkinson’s, opiate withdrawal, eczema, and menopause. 

But the most common use today, by far, is as an herbal remedy for depression.

In Germany, where St. John’s wort is available by prescription, doctors prescribe it 20 times more often than Prozac. 

" Ironically, the list of St. John’s wort’s side effects is very similar to those of antidepressant medications.

A US National Institute of Mental Health review of studies found the results on St. John’s wort to be mixed.

One study that this organization sponsored found that neither St. John’s wort nor the prescription antidepressant it was being compared to work better than a placebo. 

However, studies conducted in German-speaking countries reported more positive results than those done elsewhere.

The reason for this is unclear.

It may be that better forms of St. John’s wort are used in those countries.

It’s also been speculated that this may be due to the placebo effect since study participants in those countries were predisposed to believing in its effectiveness.

What About St. John’s Wort for Anxiety?

You may have heard that St. John’s wort can be taken for anxiety, but there’s little evidence that it is helpful.

Hyperforin boosts numerous mood-related brain chemicals, including serotonin, dopamine, noradrenaline, GABA, and glutamate.

It helps serotonin, the neurotransmitter most commonly associated with depression, bind to serotonin receptors.

It also increases the number of serotonin receptors in the brain.

Flavonoids are another group of beneficial plant compounds found in St. John’s wort.

They may help to fend off depression by protecting the brain with their potent antioxidant and anti-inflammatory properties.

St. John’s Wort Risks: Side Effects, Warnings, and Interactions

Compared to many natural remedies, St. John’s wort is rife with side effects, warnings, and drug interactions.

Here is what you need to know to determine if St. John’s wort is safe for you and whether its downsides outweigh its potential benefits.

St. John’s Wort Side Effects

One of the main reasons people want to try St. John’s wort, instead of a prescription antidepressant, is to avoid side effects.

But ironically, the list of St. John’s wort’s side effects is very similar to those of antidepressant medications — anxiety, panic attacks, dizziness, nausea, and spikes in blood pressure.

Other reported side effects include headache, fatigue, mental confusion, dry mouth, diarrhea, constipation, and stomach pain. 

St. John’s Wort and Drug Interactions

St. John’s wort is known to interact with over 500 medications. 

Sometimes, taking St. John’s wort along with a medication can cause side effects, while at other times, it can cause your medication to stop working.

St. John’s wort can weaken the effects of many prescription drugs, including antidepressants, benzodiazepines, blood thinners, painkillers, proton pump inhibitors, cholesterol-lowering drugs, and those that treat cancer and HIV. 

Women must be aware that St. John’s wort can cause their birth control pills to stop working.

St. John’s wort should be avoided by women who are pregnant or breastfeeding.

You might be tempted to use St. John’s wort to taper off your antidepressant, but you should never mix the two.

Together, they can cause a rare but serious condition called serotonin syndrome.

It may seem odd that a natural substance can interact with so many medications, but you’re probably familiar with a similar scenario.

It’s well known that many medications should not be taken with grapefruit or grapefruit juice. 

St. John’s wort, much like grapefruit, interferes with drugs by affecting the activity of certain enzymes.

Lastly, do not take St. John’s wort if you have schizophrenia or bipolar disorder as it can trigger episodes of mania. 

Caution: If you take any medications, you should not take St. John’s wort until you’ve talked to your doctor or pharmacist.

St. John’s Wort and Food Reactions

Some people experience reactions with St. John’s wort when eating foods high in the amino acid tyramine.

St. John’s Wort’s Interactions With Supplements

St. John’s wort does not safely mix with many other natural supplements.

St. John’s wort should not be taken with 5-HTP, another popular supplement for depression, anxiety, and insomnia.

When taken together, there’s a risk of serotonin syndrome.

Worryingly, many multi-ingredient mood-enhancing supplements contain both St. John’s wort and 5-HTP.

You should avoid these.

St. John’s wort works synergistically with many other herbs to enhance their beneficial actions.

But this property cuts both ways since it also increases the risk for and severity of side effects should they occur.

What to Look for in a St. John’s Wort Supplement

If you decide to give St. John’s wort a try, you’ll find a wide array of tablets, capsules, liquid extracts, dried herbs, oils, and teas available.

Most will be standardized to contain 0.3% hypericin. 

Others will contain dried flowers and leaves of the St. John’s wort plant.

Here’s a typical St. John’s wort supplement label:

The first ingredient is the standardized hypericin extract.

The second ingredient is the whole dried leaves and flowers.

The term aerials simply means the above-ground parts of the plant (not the roots).

The Best St. John’s Wort Supplement

The standardization of hypericin has led to the erroneous belief that it is St. John’s wort’s main active ingredient.

Actually, there is no strong evidence that hypericin is responsible for St. John’s wort’s antidepressant properties. 

It seems that most of St. John’s wort’s pharmacological properties come from hyperforin rather than hypericin.

Yet almost all supplements contain a standardized extract of hypericin, not hyperforin.

This is because hypericin was discovered first and has been studied longer and is a more stable compound than hyperforin.

Sixty percent of the St. John’s wort supplements tested by the independent watchdog group ConsumerLab.com did not contain what was stated on the label. 

You can’t expect to reap any of St. John’s wort’s benefits with an inferior product.

St. John’s Wort Dosage

The accepted dose of St. John’s wort is 300 – 400 mg of standardized extract (0.3% of hypericin) taken 3 times per day. 

Clinical studies have used doses of up to 1,800 mg per day for moderate to severe depression. 

Be patient when trying St. John’s wort.

It can take a few weeks to notice any improvement in depression symptoms.

However, if you don’t experience any positive effects in 4 to 6 weeks, it’s advised that you stop taking it and consider other remedies.

Safer, More Effective Alternatives to St. John’s Wort 

Understandably, you may now be leery of taking a St. John’s wort supplement.

If you are currently taking it with success, then stick with it.

But if you are one of the millions of people for whom St. John’s wort is not a viable option, there are many natural antidepressant alternatives.

You can also use proven antidepressant activities such as yoga, breathing exercises, neurofeedback, or mindfulness meditation.