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📰Read the full Sulforaphane evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ Patient taking glucoraphanin supplement without myrosinase — may be getting near-zero sulforaphane [1]
⚠ Patient cooking broccoli expecting sulforaphane benefit — boiling destroys myrosinase within 1 minute [1]
⚠ Patient on narrow-index CYP1A2 drugs (theophylline, clozapine) adding sulforaphane — enzyme induction risk [1]
⚠ Patient equating preclinical cancer data with proven cancer prevention — Qidong trial showed detoxification, not cancer endpoint [2]
🥗 Food first — build your daily Typical 10–50 mg
Check the foods you regularly eat — the bar fills toward your daily target.
Broccoli sprouts, raw (100 g)70 mg sulforaphane (approximate, raw only)
Broccoli, raw (100 g)10 mg sulforaphane (approximate, raw only)
Brussels sprouts, raw (100 g)8 mg sulforaphane (approximate, raw only)
Kale, raw (100 g)5 mg sulforaphane (approximate, raw only)
Check your regular foods above
🔬 Lab interpreter
Recommended test
No routine monitoring required
No routine monitoring required
Reference range / target
N/A
N/A
When to test
N/A
N/A
Research tool: urinary isothiocyanate metabolites [1].
Full lab monitoring ↓⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Sulforaphane is the most potent natural Nrf2 activator with a landmark RCT proving enhanced carcinogen detoxification in humans. The critical clinical decision: product selection. Glucoraphanin-only supplements without myrosinase are unreliable (10–80% individual conversion). Insist on products with myrosinase or pre-formed sulforaphane. Raw broccoli sprouts remain the cheapest, most reliable source [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
Cruciferous vegetables safe as food in pregnancy. Concentrated sulforaphane supplements not studied in pregnant women; avoid supplements [1].
👦 Pediatric: See guidance
No established pediatric dosing for supplements. Cruciferous vegetable consumption is encouraged as part of a healthy diet for children [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Take with food. Morning preferred based on pharmacokinetic studies [1].
💊 With food: No specific fat requirement. Avoid simultaneous intake of raw cruciferous vegetables with hypothyroidism medications (goitrogen concern) [1].
🚫 Avoid: Glucoraphanin-only supplements in individuals with low gut myrosinase-producing bacteria. Very high doses (>200 µmol/day) without medical supervision [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['Broccoli sprout extract (with myrosinase)', 'preferred', 'Contains glucoraphanin + active myrosinase enzyme for in vivo conversion to sulforaphane. Most reliable delivery method in supplements [1].'] | Standard | Check label | |
| ['Stabilized sulforaphane (e.g., Prostaphane®)', 'clinical', 'Pre-formed active sulforaphane. Used in clinical trials. Bypasses myrosinase requirement. More expensive [2].'] | Standard | Check label | |
| ['Glucoraphanin-only supplements', 'caution', 'Require gut bacterial myrosinase for conversion, which is highly variable between individuals (10–80% conversion rate). Unreliable [1].', 'orange'] | Standard | Check label | |
| ['Broccoli sprout powder', 'food-grade', 'Whole food form. Freeze-dried sprouts retain some myrosinase activity. Variable potency [1].'] | Standard | Check label |
3 Common questions
Why do some sulforaphane supplements not work? ▼
The most common reason is the 'bioavailability trap': many supplements contain only glucoraphanin without myrosinase enzyme. Without myrosinase (from the plant or added externally), glucoraphanin depends on gut bacteria for conversion, which varies 10–80% between individuals. Look for products containing both glucoraphanin AND myrosinase, or pre-formed stabilized sulforaphane [1].
Are broccoli sprouts really 100× more potent than broccoli? ▼
Yes, for glucoraphanin content. Broccoli sprouts (3–4 day old) contain 10–100 times more glucoraphanin per gram than mature broccoli heads. A 30 g serving of sprouts can deliver as much sulforaphane precursor as 1 kg of cooked broccoli [1].
Does cooking destroy sulforaphane? ▼
Cooking destroys myrosinase enzyme, not glucoraphanin itself. Brief steaming (≤3 minutes) partially preserves myrosinase. The 'mustard hack' — adding mustard powder after cooking — provides exogenous plant myrosinase to convert surviving glucoraphanin [1].
Can sulforaphane prevent cancer? ▼
Despite very strong preclinical evidence, no phase III cancer prevention trial has been completed in humans. The Qidong trial showed enhanced carcinogen excretion, which is a biomarker of detoxification, not direct cancer prevention evidence. Promising but unproven for cancer prevention specifically [1] [2].
4 Clinical evidence
Strong
Xenobiotic detoxification: the Qidong RCT (n=291, double-blind, placebo-controlled) demonstrated 61% increased benzene excretion and 23% increased acrolein excretion with broccoli sprout beverage over 12 weeks in a population exposed to high air pollution levels [2]. HIGH
Moderate
Nrf2 pathway activation: multiple human pharmacokinetic studies confirm dose-dependent upregulation of NQO1 and GST after sulforaphane intake [1]. Helicobacter pylori: a small RCT (n=48) showed reduced H. pylori colonization with 70 g/day broccoli sprouts for 8 weeks [1]. Type 2 diabetes: one RCT (n=97) found concentrated broccoli sprout extract reduced fasting glucose in obese patients with dysregulated diabetes [1]. MODERATE
Insufficient
Cancer prevention: despite strong preclinical data (cell cycle arrest, apoptosis induction in cancer cell lines), no completed phase III prevention trials in humans [1]. Autism spectrum disorder: 1 pilot RCT (n=44) showed improvement in behavioral scores; replication needed [1]. Neurodegeneration: preclinical only [1]. LOW
5 Safety, toxicity & adverse events
Relative
⚠ Thyroid conditions — glucosinolates are goitrogens; high intake may impair thyroid function in iodine-deficient individuals
⚠ Concurrent warfarin — sulforaphane induces CYP enzymes, potentially altering warfarin metabolism
🚩 Red flags
● Patient on theophylline or clozapine adding high-dose sulforaphane — CYP1A2 induction risk [1]
● Patient believing glucoraphanin-only supplement is delivering sulforaphane — verify myrosinase content [1]
● Hypothyroid patient consuming very high cruciferous intake — goitrogen concern at extreme doses [1]
6 Interactions
Drug interactions
Theophylline / Clozapine (CYP1A2 substrates) Moderate
Mechanism: Sulforaphane induces CYP1A2, potentially decreasing drug levels [1].
Effect: Possible reduced drug efficacy [1].
Action: Monitor drug levels if using high-dose sulforaphane supplements [1].
Levothyroxine Moderate
Mechanism: High cruciferous intake has goitrogenic potential, though sulforaphane itself is not a goitrogen [1].
Effect: Theoretical TSH increase with very high intake [1].
Action: Separate cruciferous vegetable intake from levothyroxine dosing. Monitor TSH [1].
Supplement synergies
N-Acetylcysteine (NAC) · 600 mg NAC + 30 mg sulforaphane
NAC provides cysteine for glutathione synthesis; sulforaphane upregulates GST to use that glutathione [1].
NAC provides cysteine for glutathione synthesis; sulforaphane upregulates GST to use that glutathione [1].
Selenium · 100–200 µg selenium
Selenium is a cofactor for glutathione peroxidase; synergistic with Nrf2 pathway activation [1].
Selenium is a cofactor for glutathione peroxidase; synergistic with Nrf2 pathway activation [1].
7 Regulatory
United States (FDA): Broccoli sprout extracts are marketed as dietary supplements. No FDA-approved health claims. Sulforaphane itself is not an approved drug [1].
European Union (EFSA): Available as food supplement. No authorized health claims. EFSA Novel Food regulation may apply to concentrated extracts [1].
Japan: Broccoli sprout products (e.g., Kagome brand) are popular functional foods. Japan is a major research hub for sulforaphane [1].
8 US supplement products
12
on-market products containing Sulforaphane (NIH DSLD)
Brands carrying Sulforaphane (6)
Click a brand to see its Sulforaphane products.
9 Frequently paired with
10 Cite this page
Vancouver: Pkhakadze G. Sulforaphane — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Jul 17]. Available from: https://supplement.ge/ingredients/sulforaphane/
APA 7th: Pkhakadze, G. (2026). Sulforaphane — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/sulforaphane/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: January 2027
References: 4 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Sulforaphane — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/sulforaphane/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG