Research

Hormonal

Soy isoflavones (specifically genistein and daidzein) reduce adipose tissue and improve lipid profiles in rodents through estrogen receptor (ER) and PPAR-mediated pathways, but these effects are highly dependent on sex, age, and dosage, with high pharmacological doses often required to achieve in vitro-relevant concentrations in vivo.

Soy isoflavones are not a reliable weight-loss tool for humans at typical dietary or supplemental doses. While rodent studies show fat reduction at very high, pharmacological doses, these effects are inconsistent, sex-specific, and sometimes promote fat gain in young males. The concentrations needed to see benefits in cell cultures are far higher than what humans achieve through diet. Focus on whole soy foods for general health, but do not rely on isoflavone supplements for obesity treatment.

ModerateQualifiesMEDIUM confidence
Most animal models used to elucidate the effects of isoflavones on obesity are rodent strains with either genetically or diet-induced obesity... dietary genistein at 1000 mg/kg diet does not affect body weight... dietary isoflavones significantly decrease body weight and adipose tissue... genistein is adipogenic in young, immature (4-wk-old) male mice... pharmacologic doses inhibited adipose deposition in both sexes.
Anne Ørgaard et al. · Experimental Biology and Medicine · 2008

Why this rating

The paper is a review of in vitro and rodent studies; human clinical data is sparse and inconclusive, and in vitro concentrations often exceed physiological levels.

Source

The Effects of Soy Isoflavones on Obesity

Anne Ørgaard et al. · Experimental Biology and Medicine · 2008

DOI 10.3181/0712-mr-347

narrative_reviewCited 221×
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DOI resolved against Crossref · corpus check 2026-06-10

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