What the evidence says. Graded mixed: the most rigorous, best-powered RCTs (a 2025 prediabetes trial, the children's autism trial) missed their primary endpoints, while smaller trials show benefit and a meta-analysis reports large blood-pressure drops driven by tiny studies. The mechanism (Nrf2 activation) is well established, but durable clinical benefit in humans is not. (Mixed evidence: Conflicting results across studies; benefit uncertain.)
What is Sulforaphane?
Sulforaphane is a longevity supplement used for activate nrf2 antioxidant defenses. NutriDex grades the human evidence as Mixed. Sulforaphane is an isothiocyanate formed when you chew or crush broccoli and especially broccoli sprouts, where the precursor glucoraphanin meets the enzyme myrosinase. It is a potent activator of the Nrf2 pathway, which switches on antioxidant and detoxification genes. Human trials are broad but uneven. A meta-analysis of 10 small broccoli-sprout trials reported large blood-pressure reductions (systolic ~11 mmHg), but the best-powered glucose RCT (n=89, 2025) achieved only a 0.2 mmol/L fall in fasting glucose and missed its prespecified target. In autism, an early small trial was positive but the larger replication failed its primary outcome. Sulforaphane lowers gastric oxidative-stress markers but does not reliably eradicate H. pylori, and modestly improves elevated liver enzymes in fatty-liver studies. Effect sizes are inconsistent and bioavailability varies enormously between products, so claims should be read cautiously.
Purported Benefits
✓Activate Nrf2 antioxidant defenses
✓May lower blood pressure
✓May modestly lower fasting glucose
✓Reduce gastric inflammation markers
✓Lower elevated liver enzymes
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
Outcome
Evidence
Effect
Studies
Lower blood pressureMeta-analysis of 10 broccoli-sprout trials shows ~11 mmHg systolic drop, but trials are small and heterogeneous.
Moderate
↑ benefit · moderate
1
Lower fasting glucoseBest-powered prediabetes RCT (n=89) saw only 0.2 mmol/L drop, missing its prespecified primary endpoint.
Roughly 10–40 mg sulforaphane/day (about 100–200 µmol), usually as a stabilized broccoli-sprout extract; bioavailability swings widely with myrosinase content and gut microbiota.
Generally well tolerated; the most common complaints are mild gas, bloating and reflux, and occasionally a transient rise in body temperature reported in autism trials. Because sulforaphane activates Nrf2 and can modestly lower glucose and blood pressure, theoretical additive effects with antidiabetic and antihypertensive drugs warrant monitoring. Concentrated extracts are not established as safe in pregnancy or breastfeeding, and high-dose Nrf2 activation could in theory blunt some chemotherapy agents that rely on oxidative stress, so cancer patients should consult their oncologist. Educational only — always check with your doctor or pharmacist before combining Sulforaphane with any medicine.
Sulforaphane is most often taken for Activate Nrf2 antioxidant defenses, May lower blood pressure, May modestly lower fasting glucose, Reduce gastric inflammation markers. Broccoli-sprout compound that switches on the body's Nrf2 defense genes.
Does Sulforaphane work — what does the evidence say?
Mixed evidence. Conflicting results across studies; benefit uncertain. Sulforaphane is an isothiocyanate formed when you chew or crush broccoli and especially broccoli sprouts, where the precursor glucoraphanin meets the enzyme myrosinase. It is a potent activator of the Nrf2 pathway, which switches on antioxidant and detoxification genes. Human trials are broad but uneven. A meta-analysis of 10 small broccoli-sprout trials reported large blood-pressure reductions (systolic ~11 mmHg), but the best-powered glucose RCT (n=89, 2025) achieved only a 0.2 mmol/L fall in fasting glucose and missed its prespecified target. In autism, an early small trial was positive but the larger replication failed its primary outcome. Sulforaphane lowers gastric oxidative-stress markers but does not reliably eradicate H. pylori, and modestly improves elevated liver enzymes in fatty-liver studies. Effect sizes are inconsistent and bioavailability varies enormously between products, so claims should be read cautiously.
What is the typical dose of Sulforaphane?
Roughly 10–40 mg sulforaphane/day (about 100–200 µmol), usually as a stabilized broccoli-sprout extract; bioavailability swings widely with myrosinase content and gut microbiota.
Is Sulforaphane safe? Any cautions or side effects?
Generally well tolerated; the most common complaints are mild gas, bloating and reflux, and occasionally a transient rise in body temperature reported in autism trials. Because sulforaphane activates Nrf2 and can modestly lower glucose and blood pressure, theoretical additive effects with antidiabetic and antihypertensive drugs warrant monitoring. Concentrated extracts are not established as safe in pregnancy or breastfeeding, and high-dose Nrf2 activation could in theory blunt some chemotherapy agents that rely on oxidative stress, so cancer patients should consult their oncologist.
How many studies support Sulforaphane?
NutriDex cites 9 sources for Sulforaphane, graded "Mixed".
Cite this page
APA
Peh, D. (2026). Sulforaphane: Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 16 Sept 2026, from https://nutridex.info/s/sulforaphane
BibTeX
@misc{nutridex_sulforaphane,
author = {Peh, Daryl},
title = {Sulforaphane: Benefits, Dosage, Side Effects \& Evidence},
year = {2026},
howpublished = {NutriDex --- The Supplement Research Compendium},
url = {https://nutridex.info/s/sulforaphane},
note = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-09-16}
}
For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.