Skip to main content
Evidence-Based Supplement Research
Evidence-Based Supplement Research
Pillser
Search
Sign UpLog In

Soy and Reduced Breast Cancer Recurrence

Research synthesisModerate evidenceModerate effect3 studies · 3 beneficial · 0 neutral · 0 harmful

Across 3 studies, all reported beneficial effects of soy intake on reducing breast cancer recurrence, with moderate to large effect sizes. The most-studied dose range was 25-100 mg isoflavones daily (equivalent to 2-3 servings of traditional soy foods), and the evidence primarily comes from clinical populations of women with breast cancer or breast cancer survivors.

  • Effective dose range: 25-100 mg isoflavones/day (approximately 2-3 servings of traditional soy foods)
  • Studied populations: women with breast cancer, breast cancer survivors

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Doses and forms were not consistently reported, with most studies focusing on isoflavone intake from whole soy foods rather than isolated supplements.

Generated Jul 15, 2026
Doses used in studies
  • mg/day: 20–50 (median 40, IQR 27.5–47.5) — 2 studies
Safety in these studies
3 of 3 papers
Back to top