This 2022 rodent study investigated sulforaphane’s effects on insulin resistance:

“Insulin resistance is one of the defining clinical traits of metabolic syndrome, which represents a constellation of metabolic disorders, mainly comprising obesity, type 2 diabetes mellitus, atherogenic dyslipidemia, and hypertension. This study aimed to investigate therapeutic effects and potential mechanisms of sulforaphane (SFN) on high-fat diet (HFD)-induced insulin resistance. Control chow diet was 10 kcal% fat, and HFD was 60 kcal% fat.

• SFN was found to effectively reduce body weight, fasting blood glucose, and hyperlipidemia, and improve liver function in HFD-fed mice.
• SFN led to increased expression of antioxidant genes downstream of Nrf2, and decreased accumulation of lipid peroxides MDA and 4-HNE.
• SFN significantly reduced glutathione peroxidase 4 (GPx4) inactivation-mediated oxidative stress by activating the AMPK and Nrf2 signaling pathways.

Data suggested that GPx4 could be a key target through which SFN might activate Nrf2/ARE signaling pathway to decrease the extent of insulin resistance induced in HFD-fed mice. Taken together, SFN ameliorated HFD-induced insulin resistance by activating the AMPK-Nrf2-GPx4 pathway, providing new insights into SFN as a therapeutic compound for alleviation of insulin resistance.”

https://www.sciencedirect.com/science/article/pii/S075333222200662X “Sulforaphane alleviates high fat diet-induced insulin resistance via AMPK/Nrf2/GPx4 axis”

This study’s sulforaphane dose was the same as Eat broccoli sprouts for your heart and Broccoli sprouts activate the AMPK pathway at 0.5 mg / kg. It was administered five times a week for 8 weeks to a subgroup of HFD-fed mice starting after 8 weeks of HFD.

A human equivalent oral dose to these three studies’ subcutaneous doses would be a low (0.5 mg x .081) x 70 kg = ~3 mg sulforaphane. Per Eat broccoli sprouts for your gut, my sulforaphane intake is six times that every day.