Although an ideal dosage is not known, supplementation of 0.1-0.5mg/kg sulforaphane to rats has been noted to be bioactive. This is an estimated human dose of:
7-34 mg for a 150lb person
9-45 mg for a 200lb person
11-57 mg for a 250lb person
These low quantities are likely attainable via raw broccoli or cruciferious vegetable products, while higher doses may be further beneficial. The optimal supplemental dose of sulforaphane is unknown.