Broccoli (Sulforaphane / Glucoraphanin)
Also known as: sulforaphane, glucoraphanin, Brassica oleracea var. italica, broccoli sprout extract, SGS, sulforaphane glucosinolate
Effective Dosage
No established dose from provided studies
What the Science Says
Sulforaphane is a natural compound found in broccoli and broccoli sprouts. It forms when the plant compound glucoraphanin is broken down by an enzyme called myrosinase — either during chewing or by gut bacteria. Sulforaphane activates a cellular pathway called Nrf2, which helps the body produce its own antioxidant and detoxification enzymes. Early research suggests it may support liver detox processes, reduce oxidative stress, and have anti-inflammatory effects, but most strong evidence comes from lab and animal studies rather than large human trials.
What It Doesn't Do
Not proven to prevent or treat cancer in humans — lab results don't automatically translate to people. Won't detox your body overnight. No solid evidence it boosts athletic performance. Not a substitute for eating actual vegetables. Most supplement forms have not been rigorously tested for real-world effectiveness.
Evidence-Based Benefits
Broccoli contains glucoraphanin, which is converted to sulforaphane (SFN) — an isothiocyanate that activates the Nrf2 antioxidant pathway and has demonstrated anti-inflammatory and neuroprotective properties in preliminary studies (PMID: 41752163). One small RCT found sulforaphane (30 mg/day) as an adjunct to methylphenidate significantly reduced ADHD symptom scores in children compared to placebo, with large effect sizes (Cohen's d >1.0) (PMID: 41604557). Bioavailability of sulforaphane from glucoraphanin is highly variable and depends on gut microbiome composition and the presence of myrosinase enzyme; adding exogenous myrosinase (from mustard seed) roughly doubled sulforaphane bioavailability in a crossover study (PMID: 41692762).
Weak EvidenceEffective at: No established dose from provided studies; sulforaphane doses ranged from 30 mg/day (ADHD trial) to dietary soup interventions
Source: auto-research
Absorption & Bioavailability
Variable — depends heavily on whether the supplement contains active myrosinase enzyme alongside glucoraphanin. Without myrosinase, conversion to active sulforaphane relies on gut bacteria and is inconsistent. Broccoli sprout extracts standardized with myrosinase tend to have better conversion. Cooking broccoli destroys myrosinase, reducing bioavailability from food.
Red Flags to Watch For
- Many supplements contain glucoraphanin without myrosinase, meaning little to no active sulforaphane may actually be produced in your body.
- Standardization varies wildly between brands — 'broccoli extract' on a label tells you almost nothing about actual sulforaphane content.
- High-dose sulforaphane supplements have not been well-studied for long-term safety in humans.
- Marketing often overstates cancer-prevention claims based on cell culture studies, which do not reflect human outcomes.
- People taking blood thinners or thyroid medications should consult a doctor, as high-dose cruciferous compounds may interact.
Research Sources
- General knowledge
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06