Cruciferous

Indole-3-Carbinol (I3C)

Also known as: I3C, Indole-3-carbinol, Cruciferous extract

Evidence

Cruciferous compound that converts to DIM and supports estrogen metabolism.

Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.

Add Pure Encapsulations Indole-3-Carbinol 400 mg to your stack — free

The highest-scored Indole-3-Carbinol (I3C) product in our catalog (87/100). Track dose and overlaps in the app.

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Every Indole-3-Carbinol (I3C) product we have scored

#	Product	Score	Per serving
1	Pure Encapsulations Indole-3-Carbinol 400 mg	87 A	$0.97
2	NOW Foods Indole-3-Carbinol	85 A-	$0.33
3	Natural Factors MultiFactors Women's 50+	77 B+	$0.96
4	Natural Factors AndroSense T-Correct	72 B	$1.00

Scored on dose accuracy, form, label transparency and third-party testing. Per-serving cost is list price divided by servings per container. No brand pays to be listed or ranked.

Common questions

How much Indole-3-Carbinol (I3C) should I take?

The typical range is 200-400mg daily. Ongoing for estrogen support

When should I take Indole-3-Carbinol (I3C)?

With meals. Yes.

Which form of Indole-3-Carbinol (I3C) is best?

Capsules — Standard. Other forms in the catalog: With DIM.

Is Indole-3-Carbinol (I3C) safe?

Commonly reported: GI upset, Skin rash (rare). Serious warnings: May affect hormone-sensitive conditions. May affect liver enzymes

Which Indole-3-Carbinol (I3C) supplement scores highest?

Pure Encapsulations Indole-3-Carbinol 400 mg, at 87/100. Scored on dose accuracy, form, label transparency and third-party testing — no brand pays to be listed or ranked.

Primary uses

Estrogen metabolism
Hormone balance
Detoxification

How it works

Converts to DIM in stomach
Modulates estrogen metabolism
From cruciferous vegetables
Supports healthy estrogen balance

Dosage

Typical range: 200-400mg daily
Timing: With meals
With food: Yes
Duration: Ongoing for estrogen support
Special populations: Estrogen metabolism support

Forms

Capsules
With DIM

Safety

Common side effects

GI upset
Skin rash (rare)

Contraindications

Hormone-sensitive cancers (discuss)

Products containing Indole-3-Carbinol (I3C)

Top-scoring supplements in our catalog that list Indole-3-Carbinol (I3C) on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Pure Encapsulations

Indole-3-Carbinol 400 mg

Find on Amazon

NOW Foods

Indole-3-Carbinol

Find on Amazon

Natural Factors

MultiFactors Women's 50+

Natural Factors

Evidence notes

Precursor to DIM, supports estrogen metabolism

Grade B: Some human trials support key claims; further confirmation needed.

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.