Sulforaphane

Q: How long does it take to observe the effects of sulforaphane?

Trials measure the rise in urinary elimination markers within the first days of intake, and it does not wear off: after twelve weeks of daily intake it is still at the same level. The other documented effects — fasting blood glucose, processing speed — were measured at twelve weeks.

Q: Does sulforaphane replace broccoli consumption?

No. A standardized extract provides a controlled and reproducible amount of active sulforaphane, which broccoli consumption cannot guarantee. Both approaches are complementary. A diet rich in cruciferous vegetables provides fibre, vitamins and other compounds that the extract alone does not.

Q: Can sulforaphane be taken alongside other supplements?

Sulforaphane has no documented interactions with common dietary supplements. It is compatible with vitamins, minerals and essential fatty acids. For individuals taking medications, particularly those metabolised by the liver, medical advice is recommended.

Q: Can sulforaphane be taken long-term?

The longest supplementation trials cover twelve months of daily intake, and one pilot trial ran to forty-two months, with no particular safety signal. Sulforaphane does not accumulate in the body: its mechanism relies on a transient activation that renews with each intake. A twelve-week trial also checked thyroid function specifically, and found no change.

SFN · L-Sulforaphane · Sulforafano

PhytonutrientsAutophagy & Senescence

Sulforaphane is a sulfur compound concentrated in broccoli seeds and young sprouts. Its best-supported effect in humans concerns the elimination of unwanted compounds: two controlled trials, in 291 and then 170 adults living in a heavily polluted area, measure a rise in urinary excretion of benzene derivatives, and the second establishes the exposure at which the effect appears. Two more modest signals complete the picture: fasting blood glucose in adults whose blood sugar is poorly regulated, and processing speed in older adults. With age, the cell's protection and elimination systems lose efficiency. Maintaining these internal defenses is a lever for preserving healthspan, the years lived in good health.

Last updated: August 11, 2026

Mechanism of Action

Sulforaphane belongs to the isothiocyanate family, sulfur-containing compounds that act as molecular alarm signals. Laboratory work describes a brief interaction with sentinel proteins that monitor the cell's internal stress level. This interaction releases transcription factors (proteins that command the reading of specific genes) normally kept in a dormant state.

Once released, these factors migrate to the cell nucleus and trigger, still in the laboratory, the coordinated production of protective enzymes. The process there is transient: the initial signal fades within hours, while the protective response lasts beyond it. This asymmetry between a brief stress and a prolonged defense defines the mechanism as described.

In humans, what trials measure lies downstream of those steps: the body clears more pollutant derivatives in urine, and it does so all the more as sulforaphane exposure rises.

Key Benefits

Moderate
Measurable support for clearing inhaled pollutants: in 291 adults living in a heavily polluted area, twelve weeks of a broccoli sprout beverage dosed at 600 µmol glucoraphanin and 40 µmol sulforaphane per day raise urinary elimination of benzene derivatives by 61% and of acrolein by 23%. A second trial in 170 adults reproduces the benzene effect, and only at the highest dose.
Emerging
Lower fasting blood sugar: in adults with obesity whose blood sugar remains poorly regulated, twelve weeks of a concentrated broccoli sprout extract at 150 µmol sulforaphane per day lower fasting blood glucose and glycated haemoglobin.
Emerging
A preliminary signal on mental speed: in 144 healthy adults aged 60 to 80, twelve weeks of a sulforaphane precursor at 30 mg per day improve processing speed and working memory, in a randomized placebo-controlled trial.

Dosage & Forms

Sulforaphane is available in three main supplementation forms. Free sulforaphane offers immediate bioavailability but degrades at room temperature within weeks, unless a dedicated process stabilizes it. Stabilized glucoraphanin, its biological precursor, remains stable throughout shelf life; it converts to sulforaphane in the intestine through the action of gut bacteria, a conversion whose extent varies widely from person to person. Formulations enriched with exogenous myrosinase speed up that conversion, but their effect depends on gastric conditions that are difficult to control.

Clinical trials in humans administer 25 to 340 µmol of sulforaphane per day, roughly 4 to 60 mg. Singular delivers 20 mg per day, as a broccoli seed extract standardized to 5% free, stabilized sulforaphane, which depends on no enzymatic conversion in the intestine.

In the Singular Formula

Inclusion rationale

Sulforaphane is a sulphur molecule that cabbage and broccoli release when they are chewed. In adults exposed to air pollution, controlled trials measure a rise in the urinary elimination of unwanted compounds after oral supplementation. A placebo-controlled trial also records faster thinking and better short-term memory in healthy older adults. These results, measured in humans, are what earn sulforaphane its place in the formula.

Selected form

Patented active

Sulfodyne® is a broccoli seed extract (Brassica oleracea var. italica) patented by Ingood by Olga, standardized for free, stabilized sulforaphane. Most broccoli extracts supply glucoraphanin, an inactive precursor that gut flora must hydrolyse to release sulforaphane, a conversion that depends on the microbiome and on gastric acidity. A patented stabilization process delivers the isothiocyanate directly in its active form, with no intermediate enzymatic step. European seed origin, manufactured in France.

Composition and Origin

Origin : Plant (broccoli seeds (Brassica oleracea var. italica)).

Allergens contained : None.

Allergens as traces : None.

Allergens above are declared under European Union regulations. The label of the delivered product carries the declaration applicable to your country of delivery.

How each raw material is approved

Formula dosage

0 to 20 mg.

Dose expressed as pure active substance, excluding excipients and carriers of the raw material.

Synergies in the formula

Laboratory work describes sulforaphane as a signal that switches on the enzymes which use glutathione to clear unwanted compounds. N-Acetylcysteine, for its part, supplies the cysteine required to synthesize that same glutathione. The two bioactives are selected for complementary steps of the same pathway. Selenium is a cofactor of glutathione peroxidase, one of the enzymes this protective programme mobilizes in the laboratory. Cofactor and activation signal are therefore present together in the formula. Vitamin C acts as a direct antioxidant by neutralizing free radicals in the extracellular environment, whereas sulforaphane is described as acting on antioxidant production inside the cell. These two mechanisms operate at different layers of antioxidant defense. Omega-3 fatty acids (EPA+DHA) promote inflammation resolution through the production of specific lipid mediators. Sulforaphane, for its part, is selected on the axis of clearing unwanted compounds: the two cover distinct sides of the same ground.

Linked Biomarkers

HbA1c (Glycated Hemoglobin)Fasting Blood Glucose

Safety & Precautions

Sulforaphane presents a favourable safety profile at the doses used in clinical trials. A phase I study in hospitalized volunteers, over seven days at three doses daily, recorded no abnormal events. Adverse effects reported elsewhere are limited to mild digestive discomfort (bloating, flatulence, loose stools) in a minority of participants.

During pregnancy and breastfeeding, sulforaphane supplementation is not recommended, and the Singular formula leaves it out for these profiles: at a dose equivalent to the one we deliver, a study in eight women found the molecule in umbilical cord blood, in placental tissue and in breast milk, and its effects on the child have not been studied. The product is intended for adults only.

Individuals monitored for thyroid function should inform their physician of sulforaphane intake: at very high doses, isothiocyanates may theoretically interfere with iodine metabolism. A twelve-week randomized trial nevertheless found no effect on thyroid-stimulating hormone, free thyroxine or thyroglobulin.

The track record of use is substantial. Broccoli sprouts have been part of the human diet for decades, and supplementation trials cover durations ranging from a few weeks to twelve months, with one pilot trial extended to forty-two months, and no major safety signal.

Scientific Studies

Authors	Year	Type	Journal
Egner PA et al.	2014	Randomised Controlled Trial	Cancer Prevention Research	View on PubMed
Rapid and sustainable detoxication of airborne pollutants by broccoli sprout beverage: results of a randomized clinical trial in China Randomized controlled trial in 291 adults from the Qidong region, exposed to high levels of air pollution. Twelve weeks of a broccoli sprout beverage providing 600 µmol glucoraphanin and 40 µmol sulforaphane daily increase urinary excretion of benzene conjugates by 61% and acrolein conjugates by 23%. No effect on crotonaldehyde.
Chen JG et al.	2019	Randomised Controlled Trial	The American Journal of Clinical Nutrition	View on PubMed
Dose-dependent detoxication of the airborne pollutant benzene in a randomized trial of broccoli sprout beverage in Qidong, China Randomized placebo-controlled trial in 170 adults, with three concentrations of the same beverage over ten days. Only the highest dose, the one leading to a median urinary output of 24.6 µmol of sulforaphane metabolites per day, significantly increases benzene elimination (+63.2%). The half dose (10.3 µmol) and one-fifth dose (4.3 µmol) do not differ from placebo. This trial sets the exposure to reach.
Axelsson AS et al.	2017	Randomised Controlled Trial	Science Translational Medicine	View on PubMed
Sulforaphane reduces hepatic glucose production and improves glucose control in patients with type 2 diabetes Twelve-week randomized trial. A concentrated broccoli sprout extract providing 150 µmol sulforaphane per day lowers fasting blood glucose and glycated haemoglobin in participants with obesity whose blood sugar was the least well regulated. The full text is not open access: the elements reported here are those the authors state in their abstract.
Dwibedi C et al.	2025	Randomised Controlled Trial	Nature Microbiology	View on PubMed
Effect of broccoli sprout extract and baseline gut microbiota on fasting blood glucose in prediabetes: a randomized, placebo-controlled trial The replication, and it is partial. In 74 adults with disturbed fasting blood glucose, twelve weeks of the same extract at 150 µmol per day do not meet the primary endpoint set at 0.3 mmol/L: the observed drop is 0.2 mmol/L. It concentrates on participants whose gut flora carries the gene required to convert the precursor. Gastrointestinal side effects, no serious events.
Nouchi R et al.	2021	Randomised Controlled Trial	Nutrients	View on PubMed
Brain Training and Sulforaphane Intake Interventions Separately Improve Cognitive Performance in Healthy Older Adults Four-arm double-blind randomized trial in 144 healthy adults aged 60 to 80. Twelve weeks of a supplement providing 30 mg glucoraphanin per day improve processing speed and working memory versus placebo, independently of the associated cognitive training. The authors find no correlation between the size of the gain and the amount of sulforaphane recovered in urine.
Egner PA et al.	2011	Randomised Controlled Trial	Cancer Prevention Research	View on PubMed
Bioavailability of Sulforaphane from two broccoli sprout beverages: results of a short-term, cross-over clinical trial in Qidong, China Crossover trial in 50 adults, who receive both forms in turn. Measured by urinary excretion of sulforaphane and its metabolites, bioavailability averages 70% with the sulforaphane-rich beverage versus 5% with the glucoraphanin-rich one; person-to-person variability is markedly lower with the former. This is the comparison that justifies choosing a free form.
Shapiro TA et al.	2006	Randomised Controlled Trial	Nutrition and Cancer	View on PubMed
Safety, tolerance, and metabolism of broccoli sprout glucosinolates and isothiocyanates: a clinical phase I study Double-blind, placebo-controlled phase I study in healthy hospitalized volunteers receiving the extract every eight hours for seven days. Thirty-two laboratory parameters were monitored, including transaminases and thyroid function: no abnormal event, subjective or objective, was observed. The study also establishes that the isothiocyanate form is excreted at 70.6% of dose, versus 17.8 to 19.6% for the glucosinolate form.

Frequently Asked Questions

What is the difference between sulforaphane and glucoraphanin?#[ + ]

Glucoraphanin is the stable precursor of sulforaphane, naturally present in broccoli seeds and sprouts. It has no biological activity of its own. In the intestine, gut bacteria convert it to active sulforaphane. This conversion varies from person to person, depending on the microbiome and gastric acidity. Singular selects a sulforaphane already stabilized in its active form, which does not require this step.

How long does it take to observe the effects of sulforaphane?#[ + ]

Which pollutants have trials measured an effect on?#[ + ]

Trials have measured three specific compounds, all volatile organics: benzene, whose urinary elimination rises by 61%, acrolein, by 23%, and crotonaldehyde, on which no effect was observed. The route involved is glutathione conjugation, which handles reactive organic molecules. Heavy metals, PFAS and microplastics follow other elimination routes and have been the subject of no trial with sulforaphane: we therefore claim nothing about them.

Does sulforaphane replace broccoli consumption?#[ + ]

Can sulforaphane be taken alongside other supplements?#[ + ]

Can sulforaphane be taken long-term?#[ + ]

Discover all our bioactives