St. John’s Wort Dosages: Your GoodRx Guide
Key takeaways:
St. John’s wort is an over-the-counter herbal supplement that’s often taken for depression symptoms. The most common St. John’s wort dosage for adults is 300 mg taken 3 times a day.
Look for a St. John’s wort product that contains 0.3% hypericin. And choose a supplement brand that has a certification from a third-party organization like the United States Pharmacopeia (USP).
You shouldn’t take St. John’s wort without talking to your healthcare provider first. It can interact with many medications and may not be a safe choice for you.
Table of contents
St. John’s wort is an over-the-counter (OTC) herbal supplement. It’s commonly taken to help with symptoms of depression. But St. John’s wort isn’t like prescription medications that are approved for use by the FDA. It doesn’t have a set dosage that’s been proven safe and effective.
So what’s the best St. John’s wort dosage to take? And what can you do to help protect your safety while taking it?
What’s the typical St. John's wort dosage for adults?
For depression, most St. John’s wort dosages used in studies ranged from 500 mg to 1,200 mg per day. For adults, 900 mg per day is a good St. John’s wort dosage to start with. It’s best to divide this into one 300 mg capsule taken by mouth 3 times a day. You can also start with a lower, 300 mg daily dose of St. John’s wort and increase it after a few weeks if needed.
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You can take St. John’s wort with or without food. But taking it with meals may help reduce nausea and diarrhea, which are both common St. John’s wort side effects.
St. John’s wort dosages over 1,800 mg daily aren’t recommended. Higher doses don’t seem to have a greater effect on depression symptoms. And they raise the risk of unwanted side effects and drug interactions.
Good to know: Hypericin is a compound found in the St. John’s wort plant. It’s considered a main active ingredient. A hypericin content of 0.3% is the standard for most St. John’s wort supplements. So be sure to check the hypericin content of the supplement you choose. Some labels will list both St. John’s wort extract (which contains hypericin) and St. John’s wort powder (which doesn’t). In this case, use the extract strength to determine your dose.
How long does it take St. John’s wort to kick in?
St. John’s wort may take a few weeks to start working. And side effects typically go away during this time as your body gets used to the supplement. So it’s best to stick with your starting dosage for about 4 weeks before making any changes.
Who shouldn’t take St. John’s wort?
You shouldn’t take St. John’s wort if you’re already taking medication(s) for depression or other mental health conditions. This could raise your risk of serotonin syndrome, a serious side effect caused by too much serotonin in the body.
It’s also not recommended to treat depression or other mental health symptoms on your own with herbal supplements. The best first step is to talk to your provider. They can help you make safe, informed decisions about your treatment options.
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What’s the typical St. John's wort dosage for children?
There are fewer studies available on St. John’s wort for depression in children. So it’s best to talk to their healthcare provider before giving it to your child.
A small study used St. John’s wort dosages of 300 mg to 1,800 mg daily in children under the age of 12 for depression symptoms. There weren’t any negative side effects reported, and St. John’s wort seemed to be effective for most of the children taking it after 4 to 6 weeks.
Another small study used a St. John’s wort dosage of 150 mg three times a day in children ages 6 to 16 years old. After 4 weeks, if symptoms didn’t improve, the dosage was increased to 300 mg three times a day.
A good approach to giving St. John’s wort to children is to start with a low dosage and increase it after a few weeks if needed. Your child’s provider can help you decide on the best St. John’s wort dosage to start with.
Tips for choosing a St. John’s wort product
As mentioned, St. John’s wort and other OTC supplements are less regulated than prescription medications. It’s possible for St. John’s wort supplements to contain ingredients that aren’t listed on the label. So, there are a few extra steps you should take to protect your safety when taking it.
Look for supplements labeled with United States Pharmacopeia (USP) or similar independent certifications. This means the supplement’s manufacturer took extra steps to ensure the quality of their product. Third-party testing for potency and purity is also a good sign of a reputable supplement company.
There are many different types of St. John’s wort dosage forms. Some of the most common include:
Tablets
Capsules
Liquids
Tea bags
Gummies
Lozenges
Most clinical studies use oral tablets or capsules. But that doesn’t mean other dosage forms aren’t equally effective. The best form of St. John’s wort depends on your personal preference, as long as it contains 0.3% hypericin and comes from a reputable source. Just be sure to pay attention to the serving size on the package — you may need more than one serving to get the recommended dose.
Keep in mind: You can purchase St. John’s wort over the counter, but you should still let your healthcare provider know you’re taking it. Your provider and pharmacist can also help recommend a trusted brand.
Are there any dosage adjustments for medical conditions?
Often, medical conditions like kidney or liver disease require a change in the dose of your medication. But this doesn’t seem to be the case with St. John’s wort.
That being said, St. John’s wort interacts with a number of other medications. So if you have a chronic health condition, it’s possible that St. John’s wort may interact with another medication you’re taking. This could raise or lower the levels of your medications in your body, which could make them less effective or more likely to cause side effects.
Some medications that interact with St. John’s wort include:
Migraine medications
Several statins, including atorvastatin
Warfarin
Benzodiazepines, such as alprazolam
Transplant medications, such as cyclosporine
This isn’t a full list of potential drug interactions with St. John’s wort. So be sure to give your healthcare provider or pharmacist a medication list to review for any interactions before you start taking it.
What happens if you miss a dose of St. John's wort?
If you miss your dose of St. John’s wort, take it as soon as you remember. But if it’s almost time for your next dose, skip the missed one and proceed with your usual schedule. Don’t double your next dose to make up for the one you missed.
What should you do if you take too much St. John's wort?
If you take an extra dose of St. John’s wort by mistake, it’s unlikely to cause an issue. You may notice more side effects, such as nausea and dizziness.
But a large amount of St. John’s wort can be much more of a concern. Too much St. John’s wort can lead to serotonin syndrome, which could become life threatening if it isn’t treated quickly. Early symptoms of serotonin syndrome include sweating, confusion, and a fast heart rate.
If you or someone you know takes too much St. John’s wort, contact your healthcare provider or call Poison Control at 1-800-222-1222 for instructions. If you have serious symptoms — or they seem to be getting worse — you should go to the emergency room or talk with a healthcare provider right away.
The bottom line
St. John’s wort is an over-the-counter herbal supplement that’s a common choice for depression symptoms. But it’s not an FDA-approved medication, so there’s no set recommended dosage for its use.
In most clinical studies of St. John’s wort, the usual adult dosage was 300 mg taken 3 times daily with food. This is a total of 900 mg of St. John’s wort per day. It’s also important to make sure that your product has a standardized amount of hypericin, one of the active compounds in St. John’s wort. You will want to find a product that lists the hypericin content as 0.3%.
Many medications interact with St. John’s wort, so be sure to check with your healthcare provider before trying this supplement.
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References
Findling, R. L., et al. (2003). An open-label pilot study of St. John’s wort in juvenile depression. Journal of the American Academy of Child and Adolescent Psychiatry.
Hübner, W., et al. (2001). Experience with St John's wort (hypericum perforatum) in children under 12 years with symptoms of depression and psychovegetative disturbances. Phytotherapy Research.
InformedHealth.org. (2023). Depression: Can St. John’s wort products help? Institute for Quality and Efficiency in Health Care.
Klemow, K. M., et al. (2011). Chapter 11 medical attributes of St. John’s wort (hypericum perforatum). Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition.
Loria, K. (2019). How to choose supplements wisely. Consumer Reports.
Nicolussi, S., et al. (2020). Clinical relevance of St. John's wort drug interactions revisited. British Journal of Pharmacology.
Peterson, B., et al. (2023). St John's wort. StatPearls.
Veatch-Blohm, M. E., et al. (2021). Screening for consistency and contamination within and between bottles of 29 herbal supplements. Public Library of Science One.
