Fucosterol is a plant sterol found in algae that has diverse biological activities including antioxidant, anti-inflammatory, anticancer, and antidiabetic properties among others.¹ It decreases markers of oxidative damage and increases antioxidative enzyme activity in vitro.² It reduces the expression of TNF-α and IL-6 following LPS administration by halting NF-κB and p38 MAPK signaling in RAW 264.7 murine macrophages.³ In HEK293, MCF-7, and SiHa cells, fucosterol decreases proliferation (IC50s = 185.4, 43.3, and 34.0 µg/ml, respectively).⁴ It also has anticancer activity in HL-60 leukemia cells, where it inhibits cell growth, halts the cell cycle at the G2/M transition, and induces apoptosis with maximally increased caspase-9, -8, and -3 expression at 68.8 µM.⁵ In a streptozotocin rat model of diabetes, it decreases serum glucose concentrations when administered at 30 mg/kg.⁶