Sulforaphane (with active myrosinase)

From broccoli seed and sprouts. In trials it made the body clear two air pollutants faster. It has not been shown to prevent illness, and it has not been tested for metals.

At a glance

Our verdict	For work exposure to fumes or metals, and smokers: raises excretion of some air pollutants. Stopping the exposure comes first.
Best use	Work exposure to fumes or metals; smokers
How sure the evidence is	Moderate at the trial dose; our capsule's yield is unmeasured
Cost a month	About $66 to $71

Written for adults in Canada. It explains the evidence; it is not advice for you personally. Last reviewed 20 October 2026.

Supplement Check

Is it right for you?

Sulforaphane only makes sense if you are regularly exposed to fumes or smoke, and it is never a substitute for protection or for stopping smoking. Your check asks about your work, your smoking and your medicines, and tells you what comes first. Our Supplement Check looks at:

Pregnancy, planning a pregnancy, or breastfeeding: it crosses the placenta and enters milk, and there are no safety data
Anyone on a blood thinner
Active cancer, or any cancer treatment
Allergy to broccoli, mustard or other cabbage-family vegetables
Cirrhosis of the liver
Every medicine you take

Coming soon. The Supplement Check and the Online Health Assessment open once our safety testing is complete.

$59 when it opens, paid once. Adults 18 and over, anywhere in Canada. While the service is new, Dr. French reads every report himself, and your report arrives within 3 working days. More about the Supplement Check

Tell me when it opens

What it is

Sulforaphane is not a nutrient and there is no deficiency of it. It forms when a plant enzyme, myrosinase, acts on glucoraphanin, a compound found in broccoli and richest in 3-day-old sprouts and seeds.

The form matters more than anything else. Glucoraphanin on its own, without the active enzyme, depends on gut bacteria to convert it, and only about 5 to 12% of the dose appears as sulforaphane in the urine, varying widely from person to person. [1, 2] With active myrosinase the yield is about 3 to 4 times higher. [3] Stabilised sulforaphane also works, but no Canadian-licensed product was found. Products with added piperine (black-pepper extract) are excluded, because piperine slows how the liver clears medicines.

The product we use: a glucoraphanin capsule with active myrosinase, licensed by Health Canada (your report names it). Each capsule holds 30 mg of glucoraphanin (about 69 µmol), 17 units of myrosinase and 100 mg of vitamin C. Of 42 Canadian licences checked, it is the only one that states both a glucoraphanin amount and an enzyme amount at a useful dose. [4] Its licensed claim is “a factor in the maintenance of good health” and antioxidant; it has no licensed detoxification claim. We have asked the maker for its batch test results (glucoraphanin content, enzyme activity, heavy metals, microbes); they have not yet been received.

Structure of Sulforaphane (with active myrosinase) — Structure: PubChem (public domain).

How it acts

Sulforaphane switches on a protective pathway in cells (Nrf2). That raises the liver's “phase II” enzymes, which attach benzene, acrolein and similar pollutants to glutathione so they leave the body in the urine. [5, 6] That is what the trials measured: more of these pollutants coming out in urine. Whether this lowers the risk of any illness has never been tested.

Diagram: how Sulforaphane (with active myrosinase) acts

Outline of a person showing where Sulforaphane (with active myrosinase) acts in the body

What it is used for, and what the evidence says

Almost all the evidence comes from Qidong, China, a region with high air pollution, and from smokers. No trial has been done in workers, so applying it to fumes at work is an extrapolation.

Use	What the trials found	How sure we are
Air pollutants, adults in a polluted region, 12 weeks	291 adults took a broccoli-sprout drink (600 µmol glucoraphanin plus 40 µmol sulforaphane a day). Benzene cleared in urine rose 61% and acrolein 23% against placebo; a third pollutant (crotonaldehyde) did not change. The effect started on day 1 and lasted. [5]	Moderate
The dose that works	170 adults, 10 days. Benzene clearance rose 63% at the full dose. Half and one-fifth of the dose did no better than placebo. The full dose gave about 25 µmol of sulforaphane products in the urine a day; 10 µmol did nothing. [6]	Moderate
Earlier trials in the same region	Drinks rich in either glucoraphanin or sulforaphane raised the clearance of some airborne pollutants. [7] A marker of aflatoxin (a mould toxin) damage to DNA did not differ between the groups overall. [8]	Moderate
Current smokers	49 smokers, crossover trial, glucoraphanin with active enzyme. 148 µmol a day raised benzene clearance; 296 µmol raised benzene, acrolein and crotonaldehyde clearance. [9]	Low
Former smokers at high risk of lung cancer, 12 months	43 people. No change in the airway lining under the microscope (the main measure). A marker of cell division fell 20% on sulforaphane and rose 65% on placebo. No serious side effects. [10]	Low
Heavy metals (lead, cadmium, arsenic, mercury, others)	No study in people has measured metal levels or metal excretion after sulforaphane. A 2024 systematic review found almost entirely animal and cell studies. [11]	No evidence
Long-lasting chemicals (PFAS), solvents such as toluene and xylene, vaping	Not studied in people. Plausible from how it works, nothing more.	No evidence
Cancer, lung disease, heart disease, death	No trial has measured any illness outcome.	No evidence

How sure we are: High means further research is very unlikely to change the answer; Moderate, it might; Low, it may well change; Very low, we are very unsure. These follow the GRADE method that guideline panels use.

Benefits

Benzene cleared in the urine 61 to 63% faster, acrolein 23% faster, at the trial dose (moderate certainty). [5, 6]
Whether that lowers the risk of any disease is unknown.
Low risk in trials lasting up to 12 months.

Risks and side effects

Stomach upset, gas and taste. The commonest complaints; less with seed extract than with stabilised sulforaphane.
No liver or thyroid effect in a 7-day safety study, [12] no serious side effects at 12 months [10] or in a 42-month trial of 30 mg glucoraphanin a day. [13]
Theoretical only: an effect on platelets (laboratory and mouse studies), and protection of cancer cells by the same pathway (laboratory only). These are why blood thinners and cancer treatment are on the stop list.

Interactions with medicines

In people, sulforaphane did not change the activity of CYP3A4, the liver enzyme that clears the most medicines. There is a laboratory signal on another liver enzyme (CYP1A2), not confirmed in people.

Medicine	What can happen	What to do
Blood thinners (warfarin, apixaban, rivaroxaban, others)	Licensed label warning; possible effect on platelets (laboratory only)	Held for a doctor
Chemotherapy, radiotherapy, targeted or immune therapy	Theoretical: may protect cancer cells (laboratory only)	Not during cancer treatment
Clozapine, theophylline	Laboratory signal on the enzyme that clears them	Doctor decides
Products containing piperine	Piperine slows how the liver clears medicines	We exclude these products

Who should not take it

Pregnancy, planning a pregnancy, or breastfeeding: it crosses the placenta and enters milk, and there are no safety data. One Canadian licence says not to use it; our product's licence says to consult a doctor first. [4]
Anyone on a blood thinner.
Active cancer, or any cancer treatment.
Allergy to broccoli, mustard or other cabbage-family vegetables.
Cirrhosis of the liver: a doctor decides. No specific signal in kidney or liver disease otherwise.
Under 18: outside the Supplement Check.

Dose and timing

1 capsule a day with food. This is the licensed dose and Dr. French's ruling.
Honestly: one capsule may be below the dose that worked. It holds about one-ninth of the glucoraphanin in the 12-week trial. Nobody has measured how much sulforaphane this capsule delivers; on the published conversion rates (10 to 40%), one capsule would give about 6 to 28 µmol a day, against the roughly 25 µmol that worked in the dose trial. [6, 3, 14]
Food boost: raw broccoli sprouts, or cooked broccoli with a pinch (about 1 g) of mustard-seed powder added after cooking, which raised sulforaphane more than 4-fold. [15] How much glucoraphanin sprouts contain varies, so the dose is not known.
One sulforaphane product only. If you already take a broccoli or sulforaphane product, keep it only if it is glucoraphanin with active enzyme; otherwise switch.
How to tell it is working: there is no clinical test; urine sulforaphane levels are a research measure. For lead or other metal work, the useful test is a blood lead (or urine metals) test, and it measures the exposure, not the supplement. Review at 3 months.
Store cool and dry with the lid closed: the enzyme is damaged by heat and moisture.

What we know about Canadians

CAREX Canada estimates from the 2016 census that about 966,000 Canadians are exposed to diesel exhaust at work (5% of workers; truck drivers alone 315,000), 360,000 to benzene (mechanics, couriers, taxi drivers, firefighters) and 273,000 to lead (welders 72,000, police 38,000, mechanics, plumbers). Most are in the low-exposure bands; underground miners are the main high-exposure group for diesel. [16, 17, 18]

In 2022, 10.9% of Canadians aged 15 and over smoked (men 12.9%, women 9.1%). New Brunswick had the highest rate of any province, 15.8%. [19]

Most at risk: transport and heavy-equipment drivers, mechanics, welders (especially stainless steel), firefighters, underground miners, police (lead from firing ranges), and smokers. About 9 in 10 of the exposed workers are men. These numbers show who is exposed; they do not show that any supplement lowers what is in the body.

How sure are we: moderate. Work exposure is modelled from job titles in the 2016 census, not measured; smoking is from a 2022 national survey.

An honest comparison: clearing air pollutants

No medicine increases the clearance of these pollutants. The established measure is to stop or reduce the exposure. Cost a month in Canadian dollars.

Option	Effect	How sure we are	Cost a month (CAD)
Sulforaphane at the trial dose	Benzene cleared 61% faster, acrolein 23% [5]	Moderate (pollutant clearance only)	—
Sulforaphane, 1 capsule (our dose)	Not measured; may be below the trial dose	Very low (not measured)	$66 to $71
Reduce the exposure: a respirator fitted for the hazard, extraction at the source, no eating or smoking in the work area, wash and change before going home	Removes the source; the established standard in occupational hygiene	High (established practice)	Usually employer-paid; respirator set $40 to $80
Broccoli sprouts, or broccoli with mustard powder	Same pathway; dose unknown	Low	$5 to $10 (home-grown sprouts)
For smokers: stop-smoking medicine (varenicline) or nicotine replacement	Doubles to triples the chance of quitting, which removes the exposure (not reviewed in detail here)	High	About $45 to $60; covered by many provincial plans

Read honestly: protection at work and stopping smoking come first and do far more. Sulforaphane is an add-on with a measured effect on two pollutants and no measured effect on illness.

Our verdict

For adults regularly exposed to fumes, exhaust, solvents or smoke at work (at least once a week), and for smokers: one capsule a day, after the steps that matter more. For smokers it sits in a package with soluble fibre and regular sauna, and stopping smoking comes first. Sauna is a self-care line: it is linked with fewer heart deaths in a large Finnish study, [20] but no study shows it lowers the amount of any chemical in the body, and long-lasting chemicals (PFAS) are not cleared in sweat. [21]

Not for metal exposure as a reason on its own (it has never been tested for metals), not in pregnancy or breastfeeding, not with a blood thinner or during cancer treatment. It does not replace a respirator or stopping smoking.

Dr. French recommends sulforaphane for regular exposure to fumes or smoke because, in two good randomised trials, it increased how fast the body cleared benzene and acrolein, and the risk is very low. Strong trials of illness outcomes are lacking, and we say so. He chose one capsule a day, the licensed dose, after reviewing the dose studies; the honest consequence is that its yield has never been measured and may be below the trial dose, so the report says that too. We never say it “removes toxins”: it has not been tested for metals or PFAS.