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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Standardized Insect Venom Allergenic Extract [EPC]
Hypericum Perforatum, commonly known as St. John's Wort, is a botanical active ingredient used primarily for mild-to-moderate depression. It is classified by the FDA under various EPCs including Non-Standardized Plant Allergenic Extract.
Name
Hypericum Perforatum
Raw Name
HYPERICUM PERFORATUM
Category
Standardized Insect Venom Allergenic Extract [EPC]
Drug Count
150
Variant Count
203
Last Verified
February 17, 2026
About Hypericum Perforatum
Hypericum Perforatum, commonly known as St. John's Wort, is a botanical active ingredient used primarily for mild-to-moderate depression. It is classified by the FDA under various EPCs including Non-Standardized Plant Allergenic Extract.
Detailed information about Hypericum Perforatum
References used for this content
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Hypericum Perforatum.
Hypericum Perforatum, widely recognized by its common name St. John's Wort, is a perennial flowering plant that has been utilized for medicinal purposes for over two millennia. In the modern pharmacological landscape, Hypericum Perforatum is primarily characterized as a botanical therapeutic agent with potent neurochemical properties. According to the FDA's Established Pharmacologic Class (EPC) system, it is categorized under various descriptors, most notably as a Non-Standardized Plant Allergenic Extract [EPC], though its clinical application is almost exclusively focused on its role as a natural antidepressant. It is important to note that while it is sold as a dietary supplement in the United States, in several European countries, such as Germany, it is a licensed pharmaceutical product frequently prescribed by healthcare providers for the treatment of depressive disorders.
Hypericum Perforatum belongs to a class of drugs often referred to as herbal antidepressants or phytotherapeutics. Its chemical composition is exceptionally complex, containing over seven distinct groups of active compounds. The most clinically significant constituents are the naphthodianthrones (such as hypericin and pseudohypericin) and the phloroglucinols (primarily hyperforin and adhyperforin). Other relevant compounds include flavonoids (quercetin, rutin), xanthones, and essential oils. The therapeutic efficacy of the plant is generally attributed to the synergistic action of these components, particularly hyperforin, which is believed to be the primary driver of its antidepressant activity.
Historically, Hypericum Perforatum was used by ancient Greek physicians like Hippocrates and Dioscorides for conditions ranging from wound healing to 'nerve disorders.' Today, its use is backed by a significant body of clinical evidence. A major Cochrane Review (2008) concluded that Hypericum extracts were more effective than placebo and as effective as standard synthetic antidepressants for mild-to-moderate depression, often with significantly fewer side effects. However, its regulatory status remains complex; the FDA does not approve it for the treatment of any medical condition, meaning it is marketed under the Dietary Supplement Health and Education Act (DSHEA) of 1994, which places the burden of safety and quality on the manufacturer rather than the agency.
The mechanism of action (MoA) of Hypericum Perforatum is multifaceted and differs significantly from traditional monoamine oxidase inhibitors (MAOIs) or selective serotonin reuptake inhibitors (SSRIs), although it shares some functional outcomes with them. At the molecular level, Hypericum Perforatum—specifically the component hyperforin—acts as a broad-spectrum reuptake inhibitor of several key neurotransmitters.
Unlike SSRIs, which specifically target the serotonin transporter (SERT), hyperforin appears to inhibit the reuptake of serotonin (5-HT), norepinephrine (NE), dopamine (DA), gamma-aminobutyric acid (GABA), and L-glutamate. It achieves this by increasing the intracellular concentration of sodium ions (Na+), which effectively reduces the sodium gradient that neurotransmitter transporters rely on to pull molecules back into the presynaptic neuron. By keeping these neurotransmitters in the synaptic cleft for longer periods, Hypericum Perforatum enhances mood regulation and emotional stability.
Additionally, research suggests that Hypericum Perforatum may influence the hypothalamic-pituitary-adrenal (HPA) axis, which is often overactive in individuals with depression. By modulating cortisol levels and increasing the density of serotonin receptors (5-HT2) in the brain over long-term use, the drug helps 'reset' the biological response to stress. Some studies also indicate a weak inhibition of Monoamine Oxidase A and B (MAO-A and MAO-B), though this effect is generally considered clinically insignificant at standard oral doses.
Understanding the pharmacokinetics of Hypericum Perforatum is critical due to its notorious potential for drug-drug interactions.
While Hypericum Perforatum is not FDA-approved for medical indications, it is widely utilized for the following conditions based on clinical guidelines from organizations like the World Health Organization (WHO) and the European Medicines Agency (EMA):
Hypericum Perforatum is available in various preparations, though standardization is key for clinical efficacy:
> Important: Only your healthcare provider can determine if Hypericum Perforatum is right for your specific condition. Because of its significant interaction profile, medical supervision is mandatory.
For the treatment of mild-to-moderate depression, the standard adult dosage of Hypericum Perforatum (standardized extract) is typically 300 mg taken three times daily (TID), for a total of 900 mg per day. Some clinical protocols utilize a 600 mg twice-daily regimen or a single 900 mg dose, though splitting the dose is generally preferred to maintain steady plasma levels and minimize gastrointestinal side effects.
In some cases, healthcare providers may start a patient on a lower dose (e.g., 300 mg once daily) and gradually titrate upward over two weeks to assess tolerance. It is important to look for products standardized to 0.3% hypericin or 3% to 5% hyperforin to ensure you are receiving the therapeutic levels used in clinical trials. Therapeutic effects are not immediate; it typically takes 2 to 4 weeks of consistent use before a noticeable improvement in mood occurs.
Hypericum Perforatum is generally not recommended for children under the age of 12 without direct medical supervision. For adolescents aged 12 to 18, some studies have used doses of 300 mg to 600 mg daily, but the long-term effects on the developing endocrine and neurological systems are not well-documented. Parents should always consult a pediatrician before administering any herbal supplement to a minor.
There is limited clinical data regarding the use of Hypericum Perforatum in patients with kidney disease. Because a portion of the metabolites are excreted renally, patients with a GFR (Glomerular Filtration Rate) below 30 mL/min should use this supplement with extreme caution and under close monitoring by a nephrologist.
Since Hypericum Perforatum is a potent inducer of liver enzymes, it may theoretically stress hepatic function in patients with pre-existing liver disease. Patients with Child-Pugh Class B or C hepatic impairment should generally avoid this substance unless the benefits clearly outweigh the risks, as the altered metabolism may lead to unpredictable plasma levels.
Geriatric patients (aged 65 and older) may be more sensitive to the side effects of Hypericum Perforatum, particularly dizziness and confusion. Furthermore, the high prevalence of polypharmacy (taking multiple medications) in the elderly makes the risk of dangerous drug interactions exceptionally high. Dosing should start at the lowest possible range (e.g., 300 mg daily).
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not double the dose to catch up, as this increases the risk of side effects and serotonin-related complications.
While Hypericum Perforatum has a relatively high safety margin, an acute overdose can lead to significant toxicity. Signs of overdose may include severe photosensitivity (skin redness and burning after minimal sun exposure), extreme lethargy, confusion, rapid heartbeat, and gastrointestinal distress. In the event of a suspected overdose, contact your local poison control center or seek emergency medical attention immediately. Treatment is generally supportive, focusing on hydration and protection from light.
> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose or stop taking this medication without medical guidance, as sudden discontinuation can lead to a return of depressive symptoms.
Hypericum Perforatum is generally well-tolerated, but some users may experience mild-to-moderate side effects during the first few weeks of treatment. These include:
> Warning: Stop taking Hypericum Perforatum and call your doctor immediately if you experience any of these serious reactions.
With prolonged use (exceeding 6-12 months), the primary concern is the sustained induction of liver enzymes. This can lead to 'treatment failure' for other essential medications you may be taking, such as blood pressure or heart medications. There is also a risk of developing a tolerance, where the antidepressant effects seem to diminish over time, requiring a medical re-evaluation of your treatment plan.
There are currently no FDA black box warnings for Hypericum Perforatum because it is regulated as a dietary supplement rather than a prescription drug in the United States. However, medical authorities in the UK and Europe provide strong warnings regarding its use with oral contraceptives and anticoagulants. If it were a prescription drug, it would likely carry a warning regarding suicidal thoughts and behaviors in children, adolescents, and young adults, similar to all other antidepressant medications.
Report any unusual symptoms to your healthcare provider. Keeping a 'symptom diary' during the first month of use can help your doctor determine if the side effects are transient or require a change in therapy.
Hypericum Perforatum is not a 'simple' herbal remedy; it is a pharmacologically active substance with significant systemic effects. The most critical safety point is its ability to change how your body processes other drugs. Before starting Hypericum Perforatum, you must provide your healthcare provider with a complete list of all prescription drugs, over-the-counter medications, and other supplements you are currently taking.
No FDA black box warnings for Hypericum Perforatum exist in the U.S. supplement market. However, clinical consensus suggests that the standard Antidepressant Suicide Warning should be respected: Patients of all ages who are started on therapy for depression should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behavior.
While routine lab work is not always required for healthy individuals taking Hypericum Perforatum, certain patients may need:
Hypericum Perforatum may cause dizziness, fatigue, or blurred vision in some users. Do not drive or operate heavy machinery until you know how this supplement affects you. If you experience significant drowsiness, avoid these activities entirely.
It is strongly advised to avoid alcohol while taking Hypericum Perforatum. Alcohol can worsen the sedative effects of the supplement and may increase the risk of liver toxicity. Furthermore, alcohol is a central nervous system depressant that can counteract the intended antidepressant effects of the treatment.
Do not stop taking Hypericum Perforatum abruptly. While it is not associated with a classic 'withdrawal syndrome' like benzodiazepines, a sudden stop can cause a rapid 'rebound' in the levels of other medications you are taking (because the liver enzyme induction stops). This can lead to toxicity from your other drugs. Always taper the dose down over 1 to 2 weeks under medical supervision.
> Important: Discuss all your medical conditions, including any history of liver disease, kidney disease, or bipolar disorder, with your healthcare provider before starting Hypericum Perforatum.
Hypericum Perforatum has one of the most extensive lists of drug interactions in clinical pharmacology. The following drugs must NEVER be used with it:
Hypericum Perforatum does not typically interfere with standard blood chemistry panels, but it can cause false-positive results in certain specialized urine drug screens for amphetamines due to its chemical structure. Always inform lab personnel that you are taking this supplement.
The primary mechanism is the induction of the CYP3A4 enzyme. When Hypericum 'turns on' this enzyme, the liver becomes much more efficient at breaking down other drugs. The clinical consequence is almost always a reduction in efficacy of the second drug. For drugs with a narrow therapeutic index, this can be life-threatening.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. Do not start any new medication while taking Hypericum without checking for interactions.
Hypericum Perforatum must NEVER be used in the following circumstances:
Conditions requiring a careful risk-benefit analysis by a physician include:
There is a potential for cross-sensitivity in individuals allergic to other members of the Hypericaceae family. Additionally, because it is a plant extract, individuals with severe 'weed' or 'pollen' allergies (Standardized Pollen Allergenic Extract [EPC]) may experience allergic rhinitis or skin reactions upon exposure to the supplement.
> Important: Your healthcare provider will evaluate your complete medical history, including your current drug regimen and psychiatric history, before determining if Hypericum Perforatum is a safe option for you.
Hypericum Perforatum is generally not recommended during pregnancy (Category C equivalent). Animal studies have shown conflicting results, with some suggesting potential for uterine stimulation and others showing no teratogenic effects. However, there is a lack of high-quality human data. Furthermore, its effect on liver enzymes could theoretically alter the levels of essential hormones required to maintain pregnancy. If a woman becomes pregnant while taking Hypericum, she should consult her obstetrician immediately to discuss tapering off the supplement.
Small amounts of the active constituents (hypericin and hyperforin) have been detected in breast milk. While one small study found no significant adverse effects on nursing infants, there have been isolated reports of infant colic, drowsiness, and irritability. Because the long-term effects on infant neurological development are unknown, breastfeeding mothers are generally advised to avoid its use or choose an alternative treatment for depression.
As previously mentioned, Hypericum Perforatum is not approved for use in children under 12. In adolescents, it should only be used under the strict guidance of a pediatric psychiatrist. There are concerns that its effect on multiple neurotransmitter systems could interfere with normal brain maturation during puberty.
The elderly are at the highest risk for adverse effects from Hypericum Perforatum. Age-related declines in renal and hepatic clearance can lead to higher-than-expected plasma levels. More importantly, the elderly are often on 'life-saving' medications for heart disease, diabetes, and anticoagulation, all of which interact negatively with Hypericum. Healthcare providers should prioritize non-interacting antidepressants (like certain SSRIs) in this population.
In patients with chronic kidney disease (CKD), the elimination of metabolites may be delayed. While no specific dosage guidelines exist, a 50% dose reduction is often suggested for those with moderate renal impairment, and it should be avoided in patients on dialysis due to the lack of clearance data.
Hypericum Perforatum should be used with extreme caution in patients with cirrhosis or hepatitis. The liver is the primary site of its metabolic action and its own breakdown. In impaired livers, the 'induction' effect may be unpredictable, and the risk of hepatotoxicity—though low—is increased.
> Important: Special populations require individualized medical assessment. Never start this supplement if you fall into one of these categories without first speaking to a specialist.
Hypericum Perforatum functions as a non-selective reuptake inhibitor. Its primary active component, hyperforin, inhibits the reuptake of serotonin, norepinephrine, and dopamine by inhibiting the sodium-dependent transport systems. Unlike traditional antidepressants that bind to the transporter protein itself, hyperforin increases intracellular sodium concentrations, which dissipates the electrochemical gradient required for neurotransmitter reuptake. It also has a moderate affinity for sigma receptors and acts as an antagonist at adenosine, benzodiazepine, and GABA receptors at high concentrations.
The pharmacodynamic effect of Hypericum Perforatum is characterized by a gradual onset. While neurotransmitter levels in the synapse rise shortly after ingestion, the clinical antidepressant effect requires 2-4 weeks, suggesting that downstream effects—such as the downregulation of beta-adrenergic receptors and the upregulation of 5-HT2 receptors in the frontal cortex—are the true drivers of its efficacy.
| Parameter | Value |
|---|---|
| Bioavailability | 14% - 70% (Highly variable) |
| Protein Binding | >95% (Hypericin and Hyperforin) |
| Half-life | 24 - 48 hours (Hypericin); 9 - 20 hours (Hyperforin) |
| Tmax | 2 - 6 hours |
| Metabolism | Hepatic; Potent inducer of CYP3A4, 2C9, 1A2 |
| Excretion | Fecal (approx. 80%), Renal (approx. 20%) |
Hypericum Perforatum is classified as a phytotherapeutic antidepressant. Within the FDA's EPC system, it is often grouped under Non-Standardized Plant Allergenic Extract [EPC]. It is pharmacologically distinct from but functionally similar to synthetic SSRIs and SNRIs.
Medications containing this ingredient
Common questions about Hypericum Perforatum
Hypericum Perforatum, commonly known as St. John's Wort, is primarily used for the treatment of mild-to-moderate depression. Clinical studies have shown that it can be as effective as standard SSRIs for these specific levels of depression, with the added benefit of having fewer side effects like weight gain or sexual dysfunction. In addition to mood regulation, it is sometimes used for somatoform disorders, where psychological distress manifests as physical pain. It is also occasionally utilized to help manage symptoms of menopause, such as hot flashes and irritability, often when combined with other herbs. However, it is not recommended for severe major depression or bipolar disorder. Always consult a healthcare provider to ensure it is appropriate for your specific mental health needs.
The most common side effects of Hypericum Perforatum include gastrointestinal issues such as nausea, stomach cramps, and diarrhea. Many users also report dry mouth, dizziness, and a general feeling of fatigue during the first few weeks of use. A very specific side effect is photosensitivity, where the skin becomes highly sensitive to sunlight, increasing the risk of painful sunburns or rashes. Some individuals may also experience restlessness, anxiety, or vivid dreams due to the supplement's effect on neurotransmitters like norepinephrine. Most of these side effects are mild and tend to diminish as the body adjusts to the medication. If you experience severe skin blistering or signs of an allergic reaction, you should stop use and contact a doctor immediately.
It is strongly recommended that you avoid drinking alcohol while taking Hypericum Perforatum. Alcohol is a central nervous system depressant that can worsen the very symptoms of depression the supplement is intended to treat. Furthermore, combining the two can increase the risk of side effects like dizziness, extreme drowsiness, and impaired coordination. There is also a theoretical risk that alcohol could increase the stress on your liver, as Hypericum Perforatum significantly alters liver enzyme activity. For the best therapeutic results and to ensure your safety, it is best to abstain from alcohol during your treatment. Always discuss your lifestyle habits with your doctor before starting a new supplement regimen.
Hypericum Perforatum is generally not considered safe for use during pregnancy. There is a lack of comprehensive human clinical trials to prove its safety for the developing fetus, and some animal studies suggest it could potentially stimulate uterine contractions. Additionally, because the supplement affects the liver's metabolism of hormones, it could interfere with the delicate hormonal balance required to maintain a healthy pregnancy. Most healthcare providers recommend safer, more well-studied alternatives for managing depression during pregnancy, such as specific SSRIs or psychotherapy. If you are pregnant or planning to become pregnant, you must discuss your depression treatment plan with your obstetrician. Never start or stop this supplement during pregnancy without professional medical guidance.
Hypericum Perforatum does not provide immediate relief from depressive symptoms. Like most pharmaceutical antidepressants, it typically takes between 2 to 4 weeks of consistent daily use before a patient notices a significant improvement in their mood and energy levels. This delay is due to the time it takes for the brain to adjust its receptor sensitivity and for neurotransmitter levels to stabilize in the synaptic cleft. It is important to continue taking the supplement as directed, even if you do not feel better right away. If you have been taking the standardized dose for more than 6 weeks without any improvement, you should consult your healthcare provider to re-evaluate your treatment. Do not increase your dose without medical advice.
You should not stop taking Hypericum Perforatum suddenly, especially if you have been taking it for several months. While it does not cause a traditional 'addiction,' stopping abruptly can lead to a rapid change in how your liver processes other medications you may be taking. This can cause the levels of those other drugs to rise quickly in your bloodstream, potentially leading to toxicity. Furthermore, a sudden stop can cause a 'rebound' effect where your depressive symptoms return more severely. It is best to work with your doctor to gradually taper your dose over a period of one to two weeks. This allows your neurotransmitter levels and liver enzymes to return to their baseline state safely.
If you miss a dose of Hypericum Perforatum, you should take it as soon as you remember. However, if it is nearly time for your next scheduled dose, you should skip the missed dose and simply take the next one at your regular time. You should never take two doses at once to make up for a missed one, as this can increase your risk of side effects like nausea or jitteriness. Consistency is key to the effectiveness of this supplement, so try to take it at the same times every day. Using a pill organizer or setting a phone reminder can help you stay on track. If you find yourself missing doses frequently, talk to your doctor about a more manageable dosing schedule.
One of the advantages of Hypericum Perforatum compared to many synthetic antidepressants (like tricyclic antidepressants or some SSRIs) is that it is significantly less likely to cause weight gain. In most clinical trials, weight changes in patients taking Hypericum Perforatum were similar to those taking a placebo. However, everyone's body chemistry is different, and some users might experience changes in appetite as their depression improves. If you notice significant or rapid weight changes while taking this supplement, it is important to discuss them with your healthcare provider. They can help determine if the change is related to the supplement, an improvement in your condition, or another underlying health issue.
Hypericum Perforatum is famous in the medical community for its dangerous interactions with many common medications. It can make birth control pills less effective, leading to unplanned pregnancy, and it can dangerously lower the levels of heart medications, blood thinners like warfarin, and anti-rejection drugs used after organ transplants. It also carries a high risk of causing 'Serotonin Syndrome' if taken with other antidepressants or certain migraine medications. Because of these risks, you must never combine Hypericum Perforatum with other drugs without a thorough review by a pharmacist or doctor. Always provide a full list of your medications to your healthcare team before starting this or any other herbal supplement.
Because Hypericum Perforatum is a natural plant extract, it is not 'patented' in the same way as synthetic drugs, and therefore 'generic' versions are essentially what is available in the form of various store brands and supplement labels. However, the quality and concentration of active ingredients can vary wildly between different brands. It is crucial to choose a product that is 'standardized,' meaning the manufacturer guarantees a specific amount of the active compounds hypericin (usually 0.3%) or hyperforin (usually 3-5%). Look for products with third-party certifications, such as the USP (United States Pharmacopeia) or NSF seal, to ensure that the product actually contains what the label claims and is free from contaminants.