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DIM

Supplement cruciferous compound women's healthmen's health
Aka: diindolylmethane
Brands seen in Singapore: NOW Foods, Nutricost, Micro Ingredients, Jarrow Formulas, Nature's Way
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Shifting estrogen metabolism — no clinical outcome shown
Pros & cons
Pros
  • Raises the 2-ohe1:16-ohe1 ratio in both cohorts read
  • Largest look yet at DIM and urinary estrogen profiles
Cons
  • No RCT read: both studies retrospective and exploratory
  • Authors: evidence does not support DIM for 4-ohe1
  • May shift estrogen levels in women on an e2 patch
Sources
  1. Exploring the impact of 3,3'-diindolylmethane on the urinary estrogen profile of premenopausal women (BMC Women's Health / Europe PMC 2024) — results · read 2026-08-27
    what it says
    “the 2-hydroxyestrone:16-hydroxyestrone ratio increased significantly in both the larger group and the smaller subset with results before and after DIM use.”
  2. Europe PMC 2024 DIM premenopausal cohort — conclusion · read 2026-08-27
    what it says
    “The results of this study provide the most comprehensive evaluation to date of DIM's effect on the urinary estrogen profile … suggest the need for additional studies … to fully understand the potential clinical utility of DIM.”
  3. Europe PMC 2024 DIM premenopausal cohort — statistical caveat · read 2026-08-27
    what it says
    “Because this was a data mining study using a convenience sample, no sample size or power calculation was performed a priori, and all comparisons should be considered exploratory and hypothesis generating in nature.”
  4. Europe PMC 2024 DIM premenopausal cohort — 4-hydroxyestrone · read 2026-08-27
    what it says
    “This conclusion may be surprising to some integrative and functional medicine providers who expect DIM to reduce 4-OHE1. The currently available evidence does not support DIM use for this purpose.”
  5. Europe PMC 2024 DIM premenopausal cohort — limitations (no dose recorded) · read 2026-08-27
    what it says
    “We did not collect data regarding dose or formulation of DIM/I3C, frequency of administration, or adherence.”
  6. The impact of 3,3'-diindolylmethane on estradiol and estrogen metabolism in postmenopausal women using a transdermal estradiol patch (Menopause / Europe PMC 2025) — results · read 2026-08-27
    what it says
    “women who were concurrently taking DIM had alterations in their urinary estrogen profile that included lower E1, lower E3, higher 2-OHE1, higher 4-OHE1, lower 16-OHE1, higher 2-OHE2, and lower total estrogens”
  7. Europe PMC 2025 DIM + menopausal hormone therapy — conclusion · read 2026-08-27
    what it says
    “providers treating postmenopausal women with MHT should ask their patients if they are taking a DIM supplement and, if so, consider the potential implications of drug-supplement interactions for MHT dose management and effectiveness.”
  8. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev. No. 001 (Oct 2025) · read 2026-08-27
    what it says
    “The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list”
  9. iHerb Singapore — DIM category (default order, 1 - 48 of 76 results); first 5 distinct brands in page order · read 2026-08-27
    what it says
    “NOW Foods, DIM 200, 90 Veg Capsules … Nutricost, DIM, 300 mg, 120 Capsules … Micro Ingredients, Myo & D-Chiro Inositol, 240 Vegetarian Capsules … Jarrow Formulas, DIM + CDG … Nature's Way, DIM-Plus™”
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Updated 2026-08-29. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.