Sulforaphane
1-isothiocyanato-4-(methylsulfinyl)butane
TL;DR
Sulforaphane is the best-characterized dietary Nrf2 activator, with good mechanistic and biomarker data (detox enzyme induction, airway and metabolic markers) but few hard clinical endpoints. Stabilized glucoraphanin + myrosinase products absorb far better than plain broccoli powder.
Ideal For
- People seeking antioxidant/detox enzyme support with real mechanistic backing
Avoid If
- Untreated hypothyroidism with low iodine intake
Frequently Asked Questions
Overview
Sulforaphane is formed when glucoraphanin, stored in broccoli and especially broccoli sprouts, meets the plant enzyme myrosinase after chewing or crushing. It is the most studied natural inducer of Nrf2, the transcription factor controlling phase II detoxification and antioxidant genes. Human trials consistently show increased urinary excretion of airborne pollutants (benzene, acrolein) after broccoli sprout beverages, and small studies report improvements in insulin resistance markers, autism behavioural scales and gastric Helicobacter colonization. The catch is bioavailability: most shelf products supply inactive glucoraphanin without active myrosinase, and conversion by gut bacteria is erratic, so labelled dose and delivered dose can differ several-fold.
How It Works
- Activates Nrf2 by modifying Keap1 cysteine residues
- Upregulates phase II detoxification and glutathione enzymes
- Suppresses NF-kB driven inflammatory signalling
Quick Facts
- Requires myrosinase to convert glucoraphanin into active sulforaphane
- Broccoli sprouts contain 10-100x more precursor than mature broccoli
- Most human trials use sprout extracts, not isolated sulforaphane
Benefits & Outcomes
Oxidative Damage Repair
Sulforaphane is the most compelling option because it upregulates your own antioxidant enzymes rather than acting as a one-shot scavenger.
Phase I Detox Support
Sulforaphane is the best-supported way to shift the Phase I/Phase II balance in the right direction by strongly inducing conjugation enzymes.
Phase II Detox Support
Biomarker evidence is strong and reproducible; what is missing is proof that faster conjugation translates into better long-term health outcomes.
Protein Folding Support
Sulforaphane reliably activates cellular stress defences, though proteostasis outcomes in humans are unproven.
Reduced Oxidative Stress
Sulforaphane is the best approach to oxidative stress because it boosts your own defences rather than substituting for them.
Health Concerns Addressed
No linked health concerns yet.
Supporting Research12 studies
Rapid and sustainable detoxication of airborne pollutants by broccoli sprout beverage: results of a randomized clinical trial in China
Egner PA, Chen JG, Zarth AT +15 more
Sulforaphane accelerates excretion of airborne pollutants via NRF2-mediated detoxification enzymes.
Randomized controlled trial of sulforaphane and metabolite discovery in children with Autism Spectrum Disorder
Zimmerman AW, Singh K, Connors SL +2 more
Treatment effects on the primary outcome measure, the Ohio Autism Clinical Impressions Scale (OACIS), in the general level of autism were not significant between SF and PL groups at 7 and 15 weeks.
Dose-dependent detoxication of the airborne pollutant benzene in a randomized trial of broccoli sprout beverage in Qidong, China
Chen JG, Johnson J, Egner P +1 more
Concentrations of SPMA arising through induced benzene conjugation with glutathione were quantified by MS in sequential 12-h overnight urine collections
Effects of glucosinolate-rich broccoli sprouts on urinary levels of aflatoxin-DNA adducts and phenanthrene tetraols in a randomized clinical trial in He Zuo township, Qidong, People's Republic of China
Kensler TW, Chen JG, Egner PA +1 more
Glucoraphanin, the principal glucosinolate in broccoli sprouts, can be hydrolyzed by gut microflora to sulforaphane, a potent inducer of carcinogen detoxication enzymes.
Sulforaphane treatment of autism spectrum disorder (ASD)
Singh K, Connors SL, Macklin EA +4 more
Sulforaphane produced measurable behavioural improvements in autism in this trial.
The Effects of Cruciferous Vegetable-Enriched Diets on Drug Metabolism: A Systematic Review and Meta-Analysis of Dietary Intervention Trials in Humans
Eagles SK, Gross AS, McLachlan AJ
In general, the ingestion of cruciferous vegetables is associated with induction of cytochrome P450 (CYP) 1A2 activity in vivo
Sulforaphane-rich broccoli sprout extract improves hepatic abnormalities in male subjects
Kikuchi M, Ushida Y, Shiozawa H +1 more
Dietary supplementation with BS extract containing SF precursor GR for 2 mo significantly decreased liver function markers
Effect of sulforaphane in men with biochemical recurrence after radical prostatectomy
Cipolla BG, Mandron E, Lefort JM +6 more
Sulforaphane slowed PSA rise but did not meet its primary endpoint.
A phase II study of sulforaphane-rich broccoli sprout extracts in men with recurrent prostate cancer
Alumkal JJ, Slottke R, Schwartzman J +12 more
Sulforaphane extract showed no meaningful anti-tumour activity at this dose in recurrent prostate cancer.
Dietary sulforaphane-rich broccoli sprouts reduce colonization and attenuate gastritis in Helicobacter pylori-infected mice and humans
Yanaka A, Fahey JW, Fukumoto A +1 more
Intervention with broccoli sprouts, but not with placebo, decreased the levels of urease measured by the urea breath test and H. pylori stool antigen.
Broccoli sprouts powder could improve serum triglyceride and oxidized LDL/LDL-cholesterol ratio in type 2 diabetic patients: a randomized double-blind placebo-controlled clinical trial
Bahadoran Z, Mirmiran P, Hosseinpanah F +3 more
Sulforaphane-rich broccoli sprout powder modestly improved oxidative and triglyceride markers in type 2 diabetes.
Broccoli or sulforaphane: is it the source or dose that matters?
Yagishita Y, Fahey JW, Dinkova-Kostova AT +1 more
Dose and preparation, not just sulforaphane content, determine clinical effect.
Safety Information
Potential Side Effects
Generally well tolerated. Gas, bloating and mild nausea at higher sprout-extract doses; rare allergic reactions to cruciferous plants.
Contraindications
Caution with thyroid disease when intake is very high and iodine is low; theoretical goitrogenic effect from cruciferous glucosinolates.
Pregnancy & Breastfeeding
Pregnancy: insufficient_data
Breastfeeding: insufficient_data
Dosage Guidelines
Dosage Used in Studies
20-60 mg sulforaphane equivalent
Best Form
Glucoraphanin standardized with active myrosinase
Bioavailability
Highly variable; co-delivered myrosinase raises conversion from roughly 10% to 35-40%.
Forms Compared
Preferred; mimics the sprout matrix used in trials
Directly active but unstable to heat and moisture
Usually heat-treated, myrosinase destroyed, poor conversion
Medical Disclaimer
The information provided on this website is for educational and informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any supplement regimen.
Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.