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DIM (Diindolylmethane) Side Effects & Safety

Evidence:Moderate
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This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Mild GI discomfort (nausea, gas)
  • Darkened urine (harmless)
  • Headache at higher doses
  • May alter menstrual cycle timing initially

Drug & Supplement Interactions

  • May alter estrogen-sensitive medication efficacy (tamoxifen, aromatase inhibitors)
  • May affect CYP1A2 enzyme activity — caution with caffeine and theophylline
  • May interact with hormonal contraceptives

Maximum Dose

Do not exceed: 300mg daily (higher doses not well-studied in humans)

Full DIM (Diindolylmethane) Guide

References

  1. Dalessandri KM, Firestone GL, Fitch MD, Bradlow HL, Bjeldanes LF (2004). Pilot study: effect of 3,3'-diindolylmethane supplements on urinary hormone metabolites in postmenopausal women with a history of early-stage breast cancer. Nutrition and Cancer. DOI PubMed
  2. Del Priore G, Gudipudi DK, Montemarano N, Restivo AM, Malanowska-Stega J, Arslan AA (2010). Oral diindolylmethane (DIM): pilot evaluation of a nonsurgical treatment for cervical dysplasia. Gynecologic Oncology. DOI PubMed