Sulforaphane
Also known as: Sulforaphane (SFN), Broccoli sprout extract, Isothiocyanate from glucoraphanin
Randomized trials and meta-analyses report modest improvements in some metabolic markers (insulin resistance, GLP-1, blood lipids) and small, sometimes transient, benefits on certain psychiatric symptom domains (e.g. negative symptoms/general psychopathology in schizophrenia). Systematic reviews note overall limited or low-confidence evidence for many clinical uses and do not support major adverse thyroid effects from Brassica consumption when iodine intake is adequate.
Last reviewed: 2026-10-14 · 4 indexed studies
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Overview
Sulforaphane is an isothiocyanate derived from glucoraphanin in cruciferous vegetables (notably broccoli sprouts). Human trials have investigated it for metabolic outcomes and as an adjunct in neuropsychiatric conditions, with mixed and generally modest effects.
Mechanism & Function
Mechanism of Action
Human and animal studies in the provided abstracts link sulforaphane to modulation of gut microbiota and short-chain fatty acid pathways leading to GLP-1 secretion, and to antioxidant/anti-inflammatory effects reported in clinical trials. These mechanisms are consistent with effects on insulin sensitivity and metabolic markers reported in trials.
Physiological Role
Acts as a bioactive phytochemical influencing microbial composition, inflammatory signalling and metabolic signalling (GLP-1 pathway described in preclinical and supported by trial measures).
Primary Pathways
Performance / Health Relevance
Evidence from clinical trials suggests relevance primarily to metabolic health (improved insulin resistance and lipid markers). There is no consistent evidence supporting benefits for cognitive performance from the provided trials.
Evidence Review
Practical Use & Dosage
- Minimum Effective Dose
- 42 mg/day (sulforaphane from broccoli seed tablets in an RCT reporting metabolic effects)
- Optimal Range
- Not established — clinical trials have used various doses; 42 mg/day reported in at least one human trial
- Upper / Caution Level
- Not established
- Timing
- Not established
- Best Format
- Broccoli sprout/seed extracts or standardized sulforaphane-containing preparations used in trials
- Bioavailability
- Bioavailability from glucoraphanin depends on myrosinase activity and formulation; trials have used concentrated broccoli seed/sprout products.
- Absorption Considerations
- Not established in provided abstracts
Safety & Interactions
Side Effects
- •Generally well tolerated in trials; lower discontinuation rates reported in a meta-analysis of schizophrenia trials
Contraindications
- Not established; theoretical concerns about goitrogenic effects of Brassica compounds in severe iodine deficiency, but systematic review found no adverse effects on thyroid function when iodine intake is adequate
Drug Interactions
- •Not established in provided abstracts
Who Should Avoid
- •People with known severe iodine deficiency should consult healthcare professionals; pregnant or breastfeeding women should seek advice (no data provided)
Monitoring
Monitor metabolic markers if used for metabolic indications; consider thyroid function monitoring in populations at risk of iodine deficiency.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is Sulforaphane typically used or indicated?
Sulforaphane is most commonly used for: Metabolic health (insulin resistance, lipids), Adjunctive support in psychiatric disorders (investigational), General antioxidant/anti-inflammatory support. Acts as a bioactive phytochemical influencing microbial composition, inflammatory signalling and metabolic signalling (GLP-1 pathway described in preclinical and supported by trial measures).
How does Sulforaphane work?
Human and animal studies in the provided abstracts link sulforaphane to modulation of gut microbiota and short-chain fatty acid pathways leading to GLP-1 secretion, and to antioxidant/anti-inflammatory effects reported in clinical trials. These mechanisms are consistent with effects on insulin sensitivity and metabolic markers reported in trials.
What is the recommended dose of Sulforaphane?
The optimal range is Not established — clinical trials have used various doses; 42 mg/day reported in at least one human trial. with a minimum effective dose of 42 mg/day (sulforaphane from broccoli seed tablets in an RCT reporting metabolic effects). Best taken: Not established. Upper / caution level: Not established.
What are the side effects of Sulforaphane?
Reported side effects include: Generally well tolerated in trials; lower discontinuation rates reported in a meta-analysis of schizophrenia trials. Monitoring: Monitor metabolic markers if used for metabolic indications; consider thyroid function monitoring in populations at risk of iodine deficiency.
Does Sulforaphane interact with medications?
Known or theoretical interactions: Not established in provided abstracts. Always check with a clinician before combining with prescription medication.
Who should avoid Sulforaphane?
Sulforaphane is generally not recommended for: People with known severe iodine deficiency should consult healthcare professionals; pregnant or breastfeeding women should seek advice (no data provided); and Not established; theoretical concerns about goitrogenic effects of Brassica compounds in severe iodine deficiency, but systematic review found no adverse effects on thyroid function when iodine intake is adequate.
How strong is the evidence for Sulforaphane?
Evidence level: Moderate (overall score 55/100), based on 4 indexed studies on SuppIndex.
Research & References (4)
Improving insulin resistance by sulforaphane via activating the Bacteroides and Lactobacillus SCFAs-GPR-GLP1 signal axis.
Randomized controlled trial in NAFLD patients used broccoli seed tablets rich in sulforaphane (reported as 42 mg/day) for 12 weeks alongside preclinical rat experiments linking SFN to improved insulin sensitivity via gut microbiota changes and SCFA-GPR-GLP1 signalling.
Efficacy and safety of sulforaphane in schizophrenia: a systematic review and meta-analysis of randomized controlled trials.
Meta-analysis of four randomized controlled trials in schizophrenia (369 patients) examining efficacy and safety of sulforaphane.
Pharmacological and dietary-supplement treatments for autism spectrum disorder: a systematic review and network meta-analysis.
Network meta-analysis of pharmacological and dietary-supplement treatments for autism spectrum disorder summarising 125 RCTs and 17 supplements; sulforaphane showed indications of improvement but estimates were imprecise and not robust with very low or low confidence.
Do Brassica Vegetables Affect Thyroid Function?-A Comprehensive Systematic Review.
Comprehensive systematic review assessing effects of Brassica vegetables and related compounds on thyroid function in in vitro, animal and human studies; concluded the vast majority of results cast doubt on antithyroid effects in humans and that dietary Brassica intake poses no adverse effects on thyroid function when iodine intake is adequate.
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Research Overview
Moderate EvidenceCite this ingredient
One-click citation export in APA, MLA, Chicago, BibTeX, or HTML. The URL below is stable and safe to link.
Stable URL
https://thesuppindex.com/ingredients/sulforaphane
SuppIndex. (2026). Sulforaphane: Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/sulforaphane
Based on 4 indexed studies · Evidence level: Moderate.
Goal Ratings
Stack Compatibility
No specific incompatibilities reported in the provided abstracts.