Fucoidan

Liu et al. (Int J Biol Macromol, 2025; PMID 39645105): randomized placebo-controlled trial, 70 Chinese adults with prediabetes, 1,000 mg/day for 12 weeks; a smaller rise in glycated serum protein and lower TNF-alpha, IL-6 and LPS than placebo; no lipid result is reported, so this trial does not support a lipid claim; funding not stated in the indexed record. Negishi et al. (J Nutr, 2013; PMID 24005608): randomized placebo-controlled trial, 70 Japanese adults over 60, 300 mg/day of a mekabu fucoidan for 4 weeks before influenza vaccination; higher antibody titers against all three vaccine strains than placebo; authors declare no conflicts. Against: Wright et al. (J Altern Complement Med, 2019; PMID 30312135): randomized placebo-controlled trial, 72 obese non-diabetic adults, 500 mg twice daily for 90 days, funded by the extract's maker; no difference from placebo in insulin resistance, lipids, HbA1c, fasting glucose or any other measured parameter. Hernández-Corona et al. (J Med Food, 2014; PMID 24611906): 25 overweight or obese adults, 500 mg/day for 3 months; diastolic pressure and LDL fell, but insulin, HOMA beta-cell and HOMA insulin resistance ROSE on fucoidan. Fucoidan preparations differ by seaweed source and molecular weight, so trials of different extracts do not replicate one another. Grade C: small trials of different extracts on surrogate endpoints, with a null and an adverse-direction result beside the positive ones.