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St. John’s Wort: Benefits, Uses and Potential Side Effects

St. John’s wort (Hypericum perforatum) is a bright yellow flowering plant that has been used for centuries in traditional medicine. Known for its mood-boosting properties, this herb is often taken as a natural remedy for depression and anxiety. 

The thing is, while it offers several benefits, it also comes with risks, especially when mixed with certain medications.

Let’s go over what it is and its potential risks.

What Is St. John’s Wort?

St. John’s wort is a wild-growing shrub with yellow flowers, named after St. John the Baptist because it typically blooms around his feast day (June 24). Historically, it was used in Greek, Islamic and Chinese medicine to treat wounds, nerve pain and mood disorders.

Today, it’s most commonly used in supplement form (tablets, capsules, teas, and oils) to help with:

• Mild to moderate depression
• Anxiety and stress
• Menopause symptoms (hot flashes, mood swings)
• Skin conditions (psoriasis, wound healing)

But does it really work? And is it safe?

How St. John’s Wort Affects the Brain

St. John’s wort contains hypericin and hyperforin, two key compounds believed to boost mood by:

• Increasing serotonin (the ‘feel-good’ neurotransmitter)
• Boosting dopamine & norepinephrine (linked to motivation and focus)
• Reducing inflammation (which may play a role in depression)

Does St John’s Wort Work Like an Antidepressant?

Yes, but differently than SSRIs (like Prozac). While SSRIs block serotonin reabsorption, St. John’s wort speeds up neurotransmitter turnover, making more available in the brain.

The key difference is that it may work faster than SSRIs (some people report effects in 2–4 weeks vs. 4–6 weeks for prescription meds).

St. John’s Wort Benefits: Does It Work?

So, does St. John’s wort work? Here’s what some of the scientific studies say about St. John’s wort uses:

Helps with Mild to Moderate Depression

Multiple studies suggest that St. John’s wort may be as effective as prescription antidepressants (like SSRIs) for mild to moderate depression. It works by increasing serotonin, dopamine and norepinephrine, brain chemicals that regulate mood.

It’s not, however, proven effective for severe depression, and experts warn against using it as a sole treatment without medical supervision.

Further Reading: Why Emotional Support Matters for Longevity

May Reduce Anxiety Symptoms

In terms of St. John’s wort and anxiety, some research indicates it could help with anxiety, but not social anxiety disorder, though evidence is mixed.

Further Reading: Taking Magnesium Glycinate for Anxiety

Eases Menopause Symptoms

Women going through menopause sometimes use St. John’s wort to reduce hot flashes, irritability and low mood.

If you’re struggling with menopausal symptoms, you might benefit from taking Pure NMN! Read all about how NMN can ease you through menopause.

Further Reading: Everything You Need to Know about Menopause

Potential Skin Benefits

When applied topically, St. John’s wort oil may help with wound healing, burns and psoriasis due to its anti-inflammatory properties.

Unproven or Ineffective Uses

• Severe depression (not enough evidence)
• ADHD (studies show minimal benefit)
• Chronic pain (mixed results)

St. John’s Wort Side Effects

While generally safe for short-term use (up to 12 weeks), St. John’s wort can cause:

• Digestive issues (nausea, diarrhea, upset stomach)
• Dizziness or confusion
• Dry mouth
• Fatigue or insomnia
• Increased sensitivity to sunlight (risk of sunburn)
• Sexual dysfunction (similar to SSRIs)

Rare but Dangerous Reactions to St. John’s Wort

• Serotonin Syndrome (when mixed with antidepressants): Agitation, rapid heart rate, high fever
• Psychotic episodes (in people with bipolar disorder)
• Birth defects (if taken during pregnancy)

Who Should NEVER Take St. John’s Wort?

• People on antidepressants (SSRIs, SNRIs, MAOIs)
• Organ transplant patients (interferes with immunosuppressants)
• HIV/AIDS patients (reduces antiviral effectiveness)
• Pregnant or breastfeeding women

Does St. John’s Wort Cause Weight Gain?

No strong evidence links it to weight gain, but since depression itself can affect appetite, some people may experience changes in weight.

Dangerous Drug Interactions

St. John’s wort is notorious for interacting with medications, making them less effective or increasing side effects.

Major St John’s wort drug interactions list:

• Antidepressants (SSRIs, SNRIs, MAOIs): Risk of serotonin syndrome (a life-threatening condition)
• Birth control pills: May reduce effectiveness, leading to unplanned pregnancy
• Blood thinners (warfarin): Increases clotting risk
• Certain chemotherapy medicines (irinotecan, docetaxel, imatinib): May lessen chemotherapy medicines effects
• HIV/AIDS medications: Reduces antiviral effects
• Immunosupp
• Narcotics
• Triptans
• Xanax

Case Study: St. John’s Wort & Birth Control Failure

Patient: 36-year-old woman with depression and high cholesterol.

Medications:

• Birth control: Valette® (ethinyl estradiol/dienogest): taken daily for a year.
• Other drugs: Fluvastatin (for cholesterol) and past antidepressants.

What Happened?

• She started taking St. John’s wort (Helarium® 425, up to 1700 mg/day) for depression.
• Three months later, she got pregnant despite being on birth control.

Why Did This Happen?

• St. John’s wort speeds up the breakdown of hormones in birth control, making it less effective.
• This is a known drug interaction, but she wasn’t warned because it’s an over-the-counter supplement.

Birth control failure is just one of the side effects of taking St. John’s wort. Always check with a doctor before mixing supplements with medications.

How to Take St. John’s Wort Safely (If You Must)

Dosage Guidelines for St. John’s Wort

• Standard dose: 300 mg, 3x daily (with meals)
• Maximum safe duration: 12 weeks (long-term effects are unknown)
• Best form: Standardised extract (0.3 per cent hypericin)

Safety Guidelines for St. John’s Wort

• Get a doctor’s approval first
• Stop at least 2 weeks before surgery (anaesthesia risks)
• Avoid sunlight exposure (increases burn risk)
• Monitor for mood swings (especially if bipolar)

Is St. John’s Wort FDA Approved?

The FDA does not approve St. John’s wort as a medication. Instead, it’s classified as a dietary supplement in the U.S., meaning it’s sold over the counter without FDA approval.

Dietary supplements (like St. John’s wort) don’t need FDA approval before being sold. The FDA can step in if safety concerns arise, but manufacturers are responsible for their product’s safety and labelling. In some countries (like Ireland), you need a prescription for St. John’s wort, but in the U.S., it’s available without one.

So, while it’s easy to buy, it hasn’t gone through the same strict testing as FDA-approved drugs. Always check with a doctor before using it, especially since it can interact with other medications.

End Note

St John’s Wort may be good for mild depression (if no other meds are involved), short-term anxiety relief and menopause symptom management. Just know that if you take any prescription medications, have bipolar disorder or severe depression, or are pregnant or breastfeeding, you should NOT use it.

St. John’s wort can help some people, but it’s not a harmless herb. Always speak with your doctor before trying it, especially if you’re on medications.

If you’re looking to improve your anxiety symptoms, consider taking Magnesium Glycinate 500mg. When deficient in magnesium, taking supplements may help reduce your anxiety by 30 per cent, as well as improve your sleep. It’s a simple way to boost your health in the long run.