NutriStack
DIM and Milk Thistle, a caution.
DIM shifts estrogen metabolism toward 2-hydroxylation by inducing CYP1A enzymes, while milk thistle silymarin can mildly inhibit some CYP and glucuronidation enzymes, so co-use may modestly alter estrogen handling and the clearance of other liver-metabolized compounds.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- DIM and Milk Thistle
- Pair type
- Caution
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Caution · Emerging evidence
Caution
What is happening. DIM shifts estrogen metabolism toward 2-hydroxylation by inducing CYP1A enzymes, while milk thistle silymarin can mildly inhibit some CYP and glucuronidation enzymes, so co-use may modestly alter estrogen handling and the clearance of other liver-metabolized compounds.
Mechanism. DIM acts as an aryl hydrocarbon receptor agonist that induces CYP1A1 and CYP1A2, increasing 2-hydroxyestrone formation, whereas silymarin can weakly inhibit CYP3A4, CYP2C9, and UGT-mediated glucuronidation, mainly relevant at higher exposures.
Recommendation. Generally usable together, but be aware milk thistle may modestly modulate the enzymes DIM acts on. If also taking hormone therapy or narrow-margin CYP-metabolized medications, consult a clinician before combining.
Sources (2)
- Sanderson JT, Slobbe L, Lansbergen GW, Safe S, van den Berg M. 2,3,7,8-Tetrachlorodibenzo-p-dioxin and diindolylmethanes differentially induce cytochrome P450 1A1, 1B1, and 19 in H295R human adrenocortical carcinoma cells. Toxicological Sciences. 2001.
- Venkataramanan R, Ramachandran V, Komoroski BJ, Zhang S, Schiff PL, Strom SC. Milk thistle, a herbal supplement, decreases the activity of CYP3A4 and uridine diphosphoglucuronosyl transferase in human hepatocyte cultures. Drug Metabolism and Disposition. 2000.
Stack Score
How this pair moves the number.
Effect on the composite score
If both DIM and Milk Thistle are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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