Herb Profile

St. John's Wort Hypericum Perforatum

St.

Last reviewed: •3 human studies cited

B Moderate

Use extra caution — Photosensitivity; GI symptoms; major drug interaction risk Details

Evidence
Strong Human Evidence
Typical onset
Varies by prep
Safety rating
Moderate caution
Best for
Mood Support, Antidepressant, Nervine, Stress
Avoid / review if
Pregnancy, Bipolar Disorder, Strong CYP3A4 Inducer

Monograph visual

St. John's Wort Hypericum Perforatum

The Hippie Scientist

Where to go next — guides & comparisons

Continue reading

  • If you want to browse more herbs → All herbs

Safety & Cautions

Photosensitivity; GI symptoms; major drug interaction risk

60%

Moderate caution — review before use

Detailed safety fields

Pregnancy, breastfeeding, and contraindications

  • - Pregnancy
  • - Bipolar Disorder
  • - Strong CYP3A4 Inducer
  • - Reduces Effectiveness Of Many Medications

Safety classifications

  • - Interaction-Aware: Medication or interaction context is explicitly noted.

Full safety note

  • - Photosensitivity; GI symptoms; major drug interaction risk

Safety labels

  • - Interaction-Aware

Evidence-based safety

Caution when combined

These pairings share a flagged risk mechanism. They are additive-effect cautions derived from contraindication data, not confirmed clinical interactions. Consult a clinician before combining.

High-Priority Caution

26 flagged pairings

Serotonergic activity

Browse the grouped cautions below. The list scrolls inside this card when long.

Serotonergic activity

Evidence Summary

Evidence lens

Most useful for practical interpretation when safety context also fits.

StrongStrong Human Evidence

Human clinical evidence: Present in source signals

Mechanistic / preclinical: Mechanism mapped — Neurotransmitter Modulation · Stress Response Modulation

Research maturity: Preliminary or mixed — Long Term Human Evidence May Be Limited.

Safety boundary: Safety note available — Photosensitivity; GI symptoms; major drug interaction risk

This profile cites 3 human studies.

How evidence grades work

Each grade reflects the strength and consistency of published human evidence — not marketing claims. Grades are based on study count, design quality, effect size, consistency, and recency.

A

Strong

Multiple RCTs, consistent direction, adequate effect size

B

Moderate

Some RCTs or consistent observational data in humans

C

Preliminary / Mixed

Animal or in-vitro only, or conflicting human data

D

Traditional / Theoretical

Traditional use only; no controlled human trials

Clinical Study Summaries (3)Cited studies informing this profile. RCTs and reviews shown first.
StudyTypeSampleSource

Herb-drug interactions

Fugh-Berman A et al. (2000)

——PubMed →

St. John's wort (Hypericum perforatum) and depression: what happens to the neurotransmitter systems?

Kholghi G et al. (2022)

——PubMed →

St. John's Wort

PubMed indexed authors (2006)

——PubMed →

Dosing & Timing

Dose guidance

Standardized extract (0.3% hypericin or 2 5% hyperforin): ~900 mg/day in divided doses; formulation dependent

How St. John's Wort Hypericum Perforatum Works

Simplified mechanism pathway based on preclinical and pharmacological evidence. Does not confirm clinical efficacy.

Mechanism Pathway — How St. John's Wort Hypericum Perforatum Works

How St. John's Wort Hypericum Perforatum WorksSt. John's Wort Hypericum Perforatum acts on pathways via hpa axis (modulation), leading to mood support.St. John's Wort Hypericum PerforatumBiological pathwayHPA AxisModulationMood SupportObservable outcomeSerotoninModulation
CompoundTarget / ReceptorMechanismEffect / Outcome
Mechanisms & Biological Pathways
Preclinical pathways

Proposed mechanisms from in vitro and animal research; these do not confirm clinical outcomes in humans.

Neurotransmitter ModulationStress Response Modulation

Compare & Sourcing

Compare side-by-side tradeoffs or verify active marker guidelines.

Review available sources for St. John's Wort Hypericum Perforatum

Independent database mapping — evaluated separately from safety and efficacy scores.

Check sourcing options

Affiliate Disclosure: Shopping links may earn this site a commission at no cost to you. Links are chosen on quality and availability, never commission tiers; safety warnings and evidence ratings stay independent.

Affiliate-ready sourcing

St. John's Wort product picks

Affiliate recommendations for St. John's Wort Hypericum Perforatum. Review safety, dose, and product quality before buying.

Affiliate disclosure: we may earn a commission from qualifying links at no extra cost to you. How we stay independent.

Budget pick

NOW Foods

NOW St. John's Wort 300 mg

Budget pick for standardized 0.3% hypericin St. John's Wort extract.

Check current price

Best overall

Perika

Nature's Way Perika St. John's Wort

Best overall for the clinically studied WS 5570 extract with 0.3% hypericins and 3–6% hyperforin.

Check current price

Premium pick

Thorne

Thorne St. John's Wort

Premium for a practitioner-brand standardized extract with consistent hypericin content.

Check current price
Product Form & Quality Guidelines

When sourcing St. John's Wort Hypericum Perforatum, verify the label for:

  • Standardized Extract: Confirm active content percentages on the supplement facts panel (e.g. standardized to specific marker compounds) rather than simple raw herb weights.
  • Third-Party Testing: Look for independent purity labels (USP, NSF, ConsumerLab, or Eurofins) to ensure the product is free from heavy metals, solvents, and contaminants.
  • Form Bioavailability: Ensure the form matches evidence-supported configurations (e.g. standardized active extracts like bacosides, withanolides, or curcuminoids) for optimal onset and digestion tolerance.

Compare herbs

Crocus SativusHypericum PerforatumSaffronKanna

Safety first · Harm reduction

This information is educational and not medical advice. Start low, avoid risky combinations, and consult a licensed clinician before making health decisions—especially if you use medications, have diagnosed conditions, or are pregnant/breastfeeding.

Learn how we evaluate confidence, safety, and intensity on the methodology page.

Editorial Review

Checked against primary sources, cited evidence, and contraindication language before publication. Evidence claims, safety language, and affiliate modules are reviewed independently. Not personal medical advice.

Editorial Standards →

Free safety checklist

Get the St. John's Wort Hypericum Perforatum research notes

Evidence summaries, dosing context, and safety updates for this herb — straight to your inbox.

We use your email to send the checklist and occasional evidence-first supplement updates. Unsubscribe anytime. Privacy policy.

← Back to herbs librarySafety checker →

Botanical profile context

How to interpret St. John's Wort Hypericum Perforatum

St. John's Wort dosage ranges, effects, drug interactions, and harm-reduction safety guide for mood support. Strong Human Evidence research evidence. Use this herb profile as a starting point for evidence review, not as a recommendation to start a new supplement. Botanical products can vary by plant part, extract ratio, standardization, dose, and contaminant testing, so two labels with the same common name may not behave the same way.

When reviewing St. John's Wort Hypericum Perforatum, compare the traditional-use context against the human evidence, mechanism notes, and safety cautions. Pay special attention to pregnancy, breastfeeding, liver or kidney disease, blood-pressure effects, sedation, stimulation, anticoagulant use, antidepressants, and any prescription medication overlap.

For product decisions, prefer transparent labels, named extracts, clear serving sizes, and third-party quality testing. Avoid treating a long list of possible mechanisms as proof that an herb will solve a specific condition.