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The foods high in sulforaphane are broccoli sprouts first, then broccoli heads and florets, then a few other brassicas. There is a catch: foods do not contain much sulforaphane at all. They contain glucoraphanin, and sulforaphane forms only when the plant is chopped, chewed or digested, as the papers below explain. The USDA SR Legacy database has no values for sulforaphane, glucoraphanin or any glucosinolate and no entry for broccoli sprouts, so every number here comes from a peer-reviewed paper, quoted as printed.
Peptide Labs does not sell foods or medicines. This article is general nutrition information, not medical advice. The values are measurements from published papers, not a statement about any single food on your plate.
Key Takeaways
- Sulforaphane forms from glucoraphanin when broccoli tissue is damaged; the 2019 Molecules review says intact plants hold very little free sulforaphane.
- A 1997 paper by Fahey, Zhang and Talalay reported 10 to 100 times the glucoraphanin of mature plants in 3-day-old broccoli and cauliflower sprouts.
- Supermarket broccoli heads averaged 0.38 micromoles of glucoraphanin per gram in the 2019 review's sampling, with a 200-fold range.
- In a 2008 trial by Vermeulen and colleagues, sulforaphane bioavailability was 37% from raw crushed broccoli and 3.4% from cooked.
Sulforaphane, glucoraphanin and myrosinase
The 2019 review by Yagishita, Fahey, Dinkova-Kostova and Kensler in Molecules explains that in the undamaged plant there is very little if any free sulforaphane, all of it being present as its precursor glucoraphanin, a glucosinolate built from the amino acid methionine. The review describes glucoraphanin as chemically stable and biologically inert until plant tissue is injured, by biting or chewing, and it meets the enzyme myrosinase, which the intact plant keeps physically separated from it; myrosinase splits glucoraphanin and the unstable product rearranges into sulforaphane. An NIH fact sheet on cruciferous vegetables describes glucosinolates as the sulfur-containing chemicals behind the group’s pungent aroma and bitter flavor.
Humans have a second route. The 2019 review states that mammalian cells do not produce myrosinase, but bacteria in the gut carry out the conversion, and that antibiotics can greatly reduce it. For the numbers, we checked the April 2018 release of USDA SR Legacy: its nutrient list has no row for sulforaphane, glucoraphanin or glucosinolates, and its food list has no broccoli sprouts, so the research table below stands alone.
Foods high in sulforaphane ranked: glucoraphanin from the research
The table gathers glucoraphanin and sulforaphane figures as the papers print them, in micromoles per gram of fresh weight or as ratios, with the sample described. No conversion to milligrams is made, because the papers do not make one.
| Food and sample (paper) | What was measured | Value as printed |
|---|---|---|
| Broccoli sprouts, 3 days old (Fahey 1997, PNAS) | glucoraphanin vs mature plant | 10 to 100 times higher |
| Cauliflower sprouts, 3 days old (Fahey 1997) | glucoraphanin vs mature plant | 10 to 100 times higher |
| Broccoli heads, 31 supermarket samples (2019 Molecules review) | glucoraphanin, mean | 0.38 umol/g; range under 0.005 to 1.13 |
| Broccoli, 75 field-grown hybrids, two years (2019 review) | glucoraphanin, mean | 0.88 and 1.10 umol/g |
| Broccoli heads, 32 genotypes, three years (2019 review) | glucoraphanin, mean | 0.36 umol/g |
| Broccoli, fresh and steamed, after myrosinase (Conaway 2000) | isothiocyanates | 1.1 vs 1.0 umol/g |
| Cress (McNaughton 2003, Br J Nutr) | total glucosinolates, highest in database | 389 mg/100 g |
| Pe-tsai Chinese cabbage (McNaughton 2003) | total glucosinolates, lowest in database | 20 mg/100 g |
Sprouts: the richest sulforaphane foods
Sprouts top every ranking. A 1997 paper by Fahey, Zhang and Talalay in the Proceedings of the National Academy of Sciences reported in its abstract that 3-day-old sprouts of certain crucifers, including broccoli and cauliflower, contain 10 to 100 times higher levels of glucoraphanin than the corresponding mature plants, and that sprouts of many broccoli cultivars contain negligible indole glucosinolates, the type that predominates in the mature vegetable. The 2019 review adds that glucoraphanin occurs in all tissues of the broccoli plant but is most abundant in the developing florets, with the seeds richest of all.
Chewing matters for sprouts. A 2001 study by Shapiro and colleagues compared fresh uncooked sprouts, which keep active myrosinase, with boiled sprout preparations, and its abstract reports that sulforaphane metabolite excretion was higher when intact sprouts were chewed thoroughly rather than swallowed whole, 42.4 against 28.8 micromoles. The same abstract puts isothiocyanates at about six times more bioavailable than the glucosinolates they come from.
Broccoli heads and florets: a wide range
Mature broccoli varies enormously. The 2019 review reports a sampling of 31 fresh, uncooked broccoli heads from different Baltimore-area supermarkets with a mean of 0.38 micromoles of glucoraphanin per gram of fresh weight and a range from less than 0.005 to 1.13, more than a 200-fold spread. Field trials in the same review averaged 0.88 and 1.10 micromoles per gram across more than 75 hybrid genotypes in two consecutive years, and 0.36 across 32 genotypes grown over three years. Our broccoli guide has the USDA nutrient table for the vegetable itself.
Other brassicas: foods with sulforaphane beyond broccoli
The glucoraphanin story is narrower than the cruciferous family. The 2019 review states that although two or three other edible Brassica species contain significant amounts of glucoraphanin, “it is not as widespread as popular culture would have it.” A 2019 study by Baenas and colleagues in Foods found glucoraphanin to be the main aliphatic glucosinolate of broccolini, a hybrid of broccoli and Chinese kale. Most other brassicas carry different glucosinolates: a 2003 database paper by McNaughton and Marks reports total glucosinolates from 389 milligrams per 100 grams in cress down to 20 in Pe-tsai Chinese cabbage, with a median 5.8-fold gap between the lowest and highest values for the same vegetable. Our guides cover broccolini, cauliflower, cabbage, kale, Brussels sprouts, arugula, watercress, radish, horseradish and wasabi.
Does cooking destroy sulforaphane?
Cooking acts on the enzyme more than on the precursor. A 2018 review by Oliviero, Verkerk and Dekker in Molecular Nutrition and Food Research reports that myrosinase isolated from broccoli is completely inactivated after 10 minutes at 60 degrees Celsius, and within the broccoli matrix after about 20 minutes; boiling adds leaching, with a cited review putting losses at 25% to 75% of glucosinolates into the water. Steaming, the review says, causes very little leaching and retains glucosinolates well, and microwaving without water also retains them, though myrosinase may be partly or fully inactivated depending on power and time. In the broccolini study by Baenas and colleagues, steaming retained 50% of total glucosinolates, stir-frying 41% and boiling 14%.
Human trials in three papers line up with that. In a 2008 crossover trial by Vermeulen and colleagues, eight men ate crushed broccoli raw or cooked, and sulforaphane bioavailability was 37% raw against 3.4% cooked, with the raw peak in blood at 1.6 hours and the cooked peak at 6 hours. A 2000 crossover study by Conaway and colleagues in 12 men found urinary excretion of 32.3% of ingested isothiocyanates after fresh broccoli and 10.2% after steamed. A 2007 study by Rungapamestry and colleagues compared lightly cooked broccoli, microwaved 2 minutes, with fully cooked, microwaved 5.5 minutes, and estimated a sulforaphane yield about 3-fold higher after the lightly cooked vegetable.
Two details complicate the raw-is-more picture. A 2004 study by Matusheski, Juvik and Jeffery reported in its abstract that when broccoli is crushed at room temperature the main product is sulforaphane nitrile, not sulforaphane, and that heating florets or sprouts to 60 degrees Celsius before crushing increased sulforaphane while heating to 70 degrees and above decreased it in florets but not in sprouts. And a cooked vegetable is not a lost cause: the 2018 review states that intact glucosinolates can still be hydrolyzed by gut bacteria, to a lesser extent, and a 2021 study by Abukhabta and colleagues found that adding mustard seed, a source of myrosinase, to cooked broccoli soup increased colon-available sulforaphane sixfold in 11 participants with ileostomies. See our mustard seeds guide.
Storage, freezing and fermenting
Time in the refrigerator costs some precursor. The 2018 review by Oliviero and colleagues cites reductions after 7 days at 4 to 8 degrees Celsius of 27% in broccoli, 20% in Brussels sprouts, 11% in cauliflower and 14% in green cabbage. Freezing without blanching led to a 33% loss in the review, while blanched and frozen broccoli kept both its glucosinolates and its myrosinase activity over 3 months. Fermentation goes further: the review reports complete glucosinolate degradation in white cabbage after 7 days of fermentation, so sauerkraut and kimchi are not on this list.
Natural sources of sulforaphane: what this list leaves out
This page lists natural sources of sulforaphane in food. Supplements made from broccoli seed or sprout extracts are a separate subject on which this guide makes no claims; the 2019 review’s own trial table notes that the glucoraphanin and myrosinase content of commercial products often differed from what their labels represented when the authors assayed them. Our DIM guide covers a related compound.
Raw sprouts carry a food-safety note from the FDA. The FDA page on selecting and serving produce states that sprouts served raw or lightly cooked “may contain bacteria that can cause foodborne illness,” because sprouts are grown from seeds under warm and humid conditions and a few bacteria on the seed can grow to high levels during sprouting, even at home. FDA states that people who are more vulnerable to foodborne illness “should avoid eating raw or lightly cooked sprouts of any kind”; if that describes you, ask your clinician. Cruciferous vegetables are also a vitamin K1 source, covered in our vitamin K food list; the sister list covers foods high in vitamin K2.
Frequently Asked Questions
Which food has the most sulforaphane?
Broccoli sprouts. A 1997 paper by Fahey, Zhang and Talalay reported 10 to 100 times more glucoraphanin, the sulforaphane precursor, in 3-day-old broccoli and cauliflower sprouts than in mature plants.
Is sulforaphane in broccoli itself?
Mostly as glucoraphanin. The 2019 Molecules review says intact plants hold very little free sulforaphane.
Why is sulforaphane missing from USDA nutrient tables?
USDA SR Legacy has no row for sulforaphane, glucoraphanin or glucosinolates and no broccoli sprouts entry, so this list uses peer-reviewed papers instead.
Does cooking destroy sulforaphane?
Cooking inactivates myrosinase, the enzyme that makes it. The 2008 trial by Vermeulen and colleagues measured 37% bioavailability from raw crushed broccoli and 3.4% from cooked; the 2018 review by Oliviero and colleagues reports that steaming retains glucosinolates while boiling leaches them.
Do cabbage and kale contain sulforaphane?
Less than broccoli. The 2019 review states that only two or three other Brassica species carry significant glucoraphanin; the 2003 database by McNaughton and Marks counts total glucosinolates rather than sulforaphane precursors.
Are raw broccoli sprouts a problem for anyone?
FDA states that people more vulnerable to foodborne illness should avoid raw or lightly cooked sprouts of any kind; ask your clinician if you are unsure.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines or are pregnant. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Foods High in Vitamin K2: Fermented Soybeans, Cheese, Poultry and Processed Meats, Broccoli: Nutrition, Benefits and Raw vs Cooked Facts, Cruciferous Vegetables List: The Mustard Family and USDA Data.