St. Johns Wort

St. John’s wort is well-studied for mild–moderate depression, but the evidence for treating OCD is limited and mixed. A few small open-label studies suggested possible benefit, but a larger randomized, double-blind trial found no clear advantage vs placebo. Because St. John’s wort strongly interacts with many prescription medicines and can contribute to serotonin-related adverse effects, you should not self-treat OCD with it without discussing it with a clinician.

• Active constituents: St. John’s wort contains multiple active compounds (notably hypericin and hyperforin) that affect brain chemistry. Hyperforin in particular appears to inhibit reuptake of serotonin, norepinephrine and dopamine — i.e., it can act in a way somewhat similar to antidepressants (SSRIs) that are effective for OCD. This biochemical activity is the rationale for testing SJW in OCD. BPS Publications
• Other actions: some preclinical and pharmacokinetic work shows effects on GABA/glutamate systems and on drug-metabolizing pathways — these help explain both potential benefits and risks. BPS Publications

Key point: the mechanism (serotonin reuptake inhibition, etc.) provides a plausible reason to test SJW for OCD, but biological plausibility ≠ clinical proof. For OCD, the controlled clinical evidence is limited and inconsistent. Lippincott Journals

• Common standardized dose for mood: many clinical trials for depression (and most consumer guidance) use 300 mg of a standardized extract, three times daily (≈900 mg/day) — typically standardized to 0.3% hypericin and/or specified hyperforin content. This is the usual product/dose people refer to. The Carlat Report
• Doses used in OCD research: the randomized double-blind OCD trial used a flexible dosing regimen (reported range ~600–1800 mg/day) (i.e., higher than the typical 900 mg/day and adjusted per response/tolerability). Other small open-label studies used e.g. 300 mg twice or three times daily. If someone is being treated under medical supervision the dose used in trials ranged from about 300 mg BID up to 600 mg TID (and some trials up to 1800 mg/day). Lippincott Journals+1
• Product selection: choose a standardized extract (label states hypericin and/or hyperforin content). Different brands/products vary widely in active constituents — that variability matters for both effect and interactions. The Carlat Report

How clinicians/patients typically implement this in practice (if used at all for OCD):

1. Use a standardized extract product (check label for % hypericin / mg hyperforin). The Carlat Report
2. Typical starting regimen (based on depression practice and many trials): 300 mg orally, three times daily (or as the particular standardized product’s instructions say). For OCD trials a clinician-supervised flexible dose (600–1800 mg/day) has been used; that is not standard practice outside trial settings. The Carlat Report
3. Duration: expect to wait several weeks (commonly 4–8 weeks) to judge response — trials usually ran 8–12 weeks. If no benefit by an appropriately supervised trial period, clinicians would stop it rather than continue long term for OCD without evidence. Lippincott Journals

1. Randomized double-blind trial: "St John’s wort versus placebo in obsessive–compulsive disorder" — 12-week, double-blind RCT with 60 patients (flexible dose, ~600–1800 mg/day). That controlled trial did not show a clear benefit over placebo (results were overall negative or mixed). This is the most important controlled trial addressing SJW for OCD. Lippincott Journals
2. Open-label pilot studies / case reports — small open-label trials and case reports (e.g., a 12-week open-label study with 13 subjects) reported symptomatic improvements, but open-label designs are prone to placebo effects and cannot establish efficacy. Psychiatrist.com
3. Clinical trial registry entry (NCT00035438) — trial registration describing the 12-week RCT (useful for protocol details). ICHGCP
4. Reviews / broader evidence context — systematic reviews/meta-analyses confirm SJW’s efficacy for mild–moderate depression, but explicitly note insufficient or mixed evidence for other conditions including OCD. Recent herb-for-OCD reviews call for more rigorous trials. See e.g. NCCIH summary (overview and safety), Cochrane (depression focus), and recent reviews summarizing limited OCD evidence. NCCIH

Summary: there is not robust, consistent clinical proof that St. John’s wort is an effective treatment for OCD. A few small studies suggested possible benefit, but higher-quality randomized data do not demonstrate clear, reliable benefit. Because of that, mainstream OCD treatment guidelines do not recommend SJW as a first-line or proven therapy for OCD. Lippincott Journals