A compound the body makes from cruciferous vegetables, sold concentrated to steer estrogen processing and support natural waste-clearing. Its one dependable effect is shifting estrogen breakdown toward a less growth-promoting form; other uses stay unproven. It alters liver enzymes that process medications, so long-term, high-dose use warrants caution. (Full Review)

Protocol

Dose

200–400 mg/day

Standard hormone-metabolism range

With food

Fat-containing meal

Improves absorption of active metabolites

Split dosing

Twice daily

Morning and evening meals for steadier exposure

Time to effect

Estrogen-metabolism shift

A few weeks

Biomarker change with consistent use

Clinical effects

Months

In the studied conditions

Benefits

High: Favorable shift in estrogen metabolism

Medium: Regression of cervical dysplasia; reduction of recurrent respiratory papillomatosis

Low: Hormone-sensitive cancer prevention support; induction of detoxification enzymes; improvement in benign breast conditions and cyclical breast pain

Speculative: Anti-inflammatory and immune modulation; metabolic and weight regulation; longevity and healthspan extension

Contraindications

Pregnancy and breastfeeding

Active hormone-sensitive cancer (unless supervised)

Active liver disease (decompensated, Child-Pugh Class C)

History of blood clots or stroke

Narrow-index CYP1A2/CYP3A4 drugs (clozapine, theophylline)

Key Interactions

CYP1A2 substrates (clozapine, olanzapine, theophylline, tizanidine, duloxetine)

CYP3A4 substrates (statins, calcium-channel blockers, immunosuppressants)

Caffeine and acetaminophen

Estrogen-shifting supplements (DIM, sulforaphane, calcium-D-glucarate, chrysin, flaxseed lignans)

Risk & Side Effects

High: Induction of drug-metabolizing enzymes

Medium: Gastrointestinal upset; tumor promotion at high or chronic doses

Low: Hormonal disruption; neurological effects at high doses; elevated liver enzymes; clotting and stroke reports with DIM

Speculative: Thyroid suppression; reduced efficacy of hormonal therapies

Monitoring

Marker	Target	Why
2-Hydroxyestrone : 16α-hydroxyestrone ratio (urine)	> 2.0	Direct readout of the main estrogen-handling effect
Estradiol (E2)	Sex- and cycle-specific, mid-range	Detects excessive lowering or imbalance of estrogen
ALT	< 25 U/L (women), < 30 U/L (men)	Screens for the uncommon liver-enzyme elevation
TSH	0.5–2.5 mIU/L	Screens for the theoretical goitrogenic effect
Free T4	Mid-to-upper reference range	Confirms thyroid status alongside TSH

Cadence: Baseline before starting; recheck at 6–12 weeks, then every 6–12 months or at any dose change

Qualitative Assessment

Cyclical breast tenderness or fullness
Menstrual regularity and premenstrual symptoms in women
Energy, digestion, and any nausea or bowel changes signaling intolerance
General well-being, with attention to any new balance or neurological symptoms at higher doses

Indole-3-Carbinol for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment