What St. John's Wort Is
St. John's Wort is the flowering top of Hypericum perforatum, a yellow-flowered plant that blooms around midsummer. Remedy's St. John's Wort supplies 1000 mg of the dried flowers and leaves per vegan capsule, with 60 capsules per bottle. It is whole herb, not a standardised extract.
It is one of the most studied herbs on these shelves, and it is also the one with the longest list of drug interactions. This page covers both, in that order of importance.
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1000 mg per capsule: Dried flowers and leaves, nothing concentrated.
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60 capsules: Two months at 1 daily.
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Named constituents: Hypericin and hyperforin.
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The key caution: It lowers the level of many prescription drugs.
The full evidence map is in our St. John's Wort overview.
Supplement Facts
Serving size: 1 Vegan Capsule. Servings per container: 60.
| Amount Per Serving |
Amount |
% Daily Value |
| St. John's Wort (Hypericum perforatum) flowers and leaves |
1000 mg |
* |
* Daily Value not established.
Other ingredients: Cellulose, Glycerin, Water (vegan capsule)
Directions: One capsule daily, after checking your other medicines with a pharmacist.
Made in the USA.
Read This First: Drug Interactions
This is the most important section on the page. St. John's Wort switches on CYP3A4 and the P-glycoprotein pump, which clear many drugs, so those drugs can fall below the level that works.
| Medicine |
What was measured |
| The combined pill |
More breakthrough bleeding; probable ovulation in 1 trial |
| Cyclosporine and tacrolimus (transplant) |
Lower drug levels; cyclosporine exposure down 52% |
| Indinavir and other HIV drugs |
Indinavir exposure down 57% |
| Warfarin (blood thinner) |
Faster clearance and a weaker effect on INR |
| Digoxin (heart) |
Exposure down 25% after 10 days |
| SSRIs and other serotonin drugs |
Risk of serotonin syndrome |
Hyperforin, one of the herb's constituents, is a potent activator of the receptor that switches this system on, and CYP3A4 handles more than half of all drugs.[1]St. John's wort induces hepatic drug metabolism through activation of the pregnane X receptor — PNAS (2000) View source In 10 kidney transplant patients, a high-hyperforin product cut cyclosporine exposure by 52%.[2]Hyperforin content determines the magnitude of the St John's wort-cyclosporine drug interaction — Clinical Pharmacology and Therapeutics (2004) View source The full list is in St. John's Wort drug interactions.
Whole Herb, Not a Standardised Extract
Most studies used 900 mg a day of a standardised extract, split into 3 doses. Our capsule is 1000 mg of whole herb, and the two numbers are not comparable.
|
In most studies |
In this capsule |
| Form |
Standardised extract |
Whole dried herb |
| Daily amount |
900 mg, as 3 x 300 mg |
1000 mg, as 1 capsule |
| Hypericin stated |
Often 0.3% |
Not stated |
| Hyperforin stated |
Sometimes 1 to 4% |
Not stated |
A whole herb is not interaction-free either. In 42 men, 2.7 g a day of powdered herb still cut exposure to a marker drug by 47.9%, and the effect tracked hyperforin rather than hypericin.[3]The extent of induction of CYP3A by St. John's wort varies among products and is linked to hyperforin dose — European Journal of Clinical Pharmacology (2006) View source We do not print a hyperforin figure, so treat this capsule as fully interacting. More in St. John's Wort dosage and standardization.
What the Research Has Studied
Rather than print a benefits list, we would rather print the shape of the literature. These counts came off PubMed and anyone can rerun them.
| What PubMed holds on St. John's Wort |
Count |
| Records on St. John's Wort or Hypericum |
4,020 |
| Randomized or clinical trials |
244 |
| Systematic reviews or meta-analyses |
120 |
| Trials in depression |
102 |
| Records on drug interactions |
862 |
Most of that research concerns mood. Reviews of standardised extracts report results in mild to moderate depression over 4 to 12 weeks, and flag the lack of research in severe depression.[4]A systematic review of St. John's wort for major depressive disorder — Systematic Reviews (2016) View source Two large US trials in moderately severe major depression were negative. Those findings concern specific extracts, not this capsule, and this product is not a replacement for any prescribed treatment. The detail is in St. John's Wort for depression.
The Pill and Other Hormonal Contraception
Both hormones in a combined pill are cleared by the enzyme this herb switches on.
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Breakthrough bleeding: 2 of 12 women before, 7 of 12 with the herb.
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Probable ovulation: Seen in 1 small trial.
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Other methods: Implants, injections and hormonal IUDs were not tested.
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Trial advice: Consider a barrier method if you take both.
The 2003 trial that measured the bleeding also advised adding a barrier method.[5]The interaction between St John's wort and an oral contraceptive — Clinical Pharmacology and Therapeutics (2003) View source Anyone relying on hormonal contraception should read St. John's Wort and birth control before buying.
Antidepressants and Serotonin
Never combine this herb with an SSRI or any other serotonin-acting medicine.
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The risk: Serotonin syndrome, with agitation, sweating, fast heartbeat and fever.
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Case evidence: 5 older adults in a 1999 series.
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Switching: A prescriber decision, never a solo one.
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5-HTP: Also serotonergic, so never combine the two.
The 1999 case series described 5 cases of serotonin syndrome in older adults who combined prescription antidepressants with the herb.[6]St. John's wort and antidepressant drug interactions in the elderly — Journal of Geriatric Psychiatry and Neurology (1999) View source More in St. John's Wort and SSRIs.
Side Effects and Sun Sensitivity
At ordinary doses the side-effect record is mild. In 35 double-blind trials, dropouts and side effects were similar to placebo.[7]Adverse effects of St. John's Wort: a systematic review — Journal of Clinical Psychiatry (2004) View source
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Common: Stomach upset, dizziness, headache.
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Sleep and energy: Trouble sleeping and restlessness.
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Sun: A small rise in sensitivity at high doses.
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Stop and ask: For a rash, agitation or confusion.
At 1800 mg a day of extract, the change in light sensitivity was offset by about 21% less time in the sun.[8]Hypericin and pseudohypericin: pharmacokinetics and effects on photosensitivity in humans — Pharmacopsychiatry (1997) View source More in St. John's Wort side effects and sun sensitivity.
Who Should Not Take It
Because of the enzyme effect, this list is longer than for most herbs.
| Situation |
Position |
| Taking any prescription medicine |
Check with a pharmacist first |
| Taking an antidepressant or 5-HTP |
Do not combine |
| Relying on hormonal contraception |
Read the contraception section first |
| Pregnant or breastfeeding |
Not established as safe, so avoid |
| History of mania or bipolar disorder |
Only with a psychiatrist involved |
| Surgery planned |
Tell your surgical team you take it |
If you have any thought of self-harm, that needs same-day help rather than a supplement: call or text 988 in the US.
How to Use It
One capsule daily, and only after a pharmacist has checked your other medicines.
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Timing: Morning suits people whose sleep is affected.
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Duration: Most studies ran 4 to 12 weeks.
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Stopping: The enzyme effect fades over about 7 days.
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One source only: Our Depression Tamer also contains St. John's Wort.
Why Choose Remedy's St. John's Wort
No trial makes one herb capsule better than another, so the honest differentiators are what is in it and what the page is willing to say.
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Single ingredient: St. John's Wort, with 0 other actives.
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Described accurately: Whole herb, not presented as the trial extract.
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Interactions first: The medicine check is on the page, not hidden.
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No replacement claim: It is not sold as a substitute for prescribed treatment.
Frequently Asked Questions
What is St. John's Wort? +
A yellow-flowered herb, Hypericum perforatum. Each capsule holds 1000 mg of the dried flowers and leaves.
How much is in 1 capsule? +
1000 mg of whole herb. It is not a standardised extract, so no hypericin or hyperforin percentage is stated.
Is this the same as the 900 mg extract used in studies? +
No. Extracts are concentrated from more herb, so 1000 mg of herb and 900 mg of extract are 2 different measures.
Does it interact with medications? +
Yes. It speeds up the clearance of many drugs, including the pill and warfarin, and in 1 trial cut cyclosporine exposure by 52%. Check with a pharmacist first.
Can I take it with an antidepressant? +
No. Combining it with an SSRI or another serotonin-acting drug risks serotonin syndrome, and a 1999 series described 5 cases.
Does it affect birth control? +
It can. In 1 trial, breakthrough bleeding rose from 2 of 12 to 7 of 12 women on the pill.
Does it make you sensitive to the sun? +
Slightly, at high doses. At 1800 mg a day of extract the change was offset by about 21% less sun time.
Is it safe in pregnancy? +
It is not established as safe in pregnancy or breastfeeding, the 2 groups who should avoid it.
How long does 1 bottle last? +
Sixty capsules is 2 months at 1 capsule daily.
When should I take it? +
1 capsule daily. Mornings suit people whose sleep is affected, since trouble sleeping is a listed side effect.
Does the effect on other medicines stop when I stop? +
It fades over about 7 days after the last capsule, so tell prescribers if you took it recently.
Can I take it with Depression Tamer? +
No. Depression Tamer already contains St. John's Wort, so taking both doubles up 1 herb.
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