library.onepin.app/i3c Peptide Education Library
Education only, not medical advice 21+ Every dose is an example to finalize with a licensed provider
Hormonal Dietary supplementIndole-3-Carbinol (Cruciferous Phytochemical)

I3C

Indole-3-Carbinol

200-400mg daily – 200 mg Oral 1-2x daily
Estrogen Metabolism ModulatorPolymerizes to DIM in Stomach

I3C (Indole-3-Carbinol) is a phytochemical found in cruciferous vegetables (broccoli, cabbage, cauliflower, Brussels sprouts). Under stomach acid conditions, I3C polymerizes to form DIM (Diindolylmethane) and other indole compounds - the actual bioactive metabolites in vivo. This is why DIM supplementation is often preferred (more direct delivery of the active compound).

Quick Start
Route
Oral capsule
Start low
200-400mg Oral
Frequency
1-2x daily
Timing
With food (acid environment supports DIM conversion)

With meals.

Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.

Tiered Protocols · lowest first
Conservative start
200-400mg daily · Oral capsule · 1-2x daily
conservative starter
200-400mg daily
1-2x daily
Standard
Estrogen Metabolism
200 mg · Oral · 2x Daily
human study · Michnovicz et al. 1997 (J Natl Cancer Inst)
Precursor to DIM. Unstable in stomach acid, converting into DIM and other active metabolites.
200 mg
2x Daily
01

How it works

I3C and its in vivo metabolites act via:

Stomach Acid Polymerization

I3C is unstable in stomach acid - polymerizes to DIM and other indole compounds. DIM is the active form.

CYP1A1 Induction

Shifts estrogen metabolism toward 2-hydroxyestrone (less proliferative) over 16α-hydroxyestrone (more proliferative). Theoretical benefit in estrogen-driven conditions.

Aryl Hydrocarbon Receptor (AhR) Modulation

AhR ligand activity drives Phase 1/2 detox enzyme upregulation.

Anti-Estrogenic at Cellular Level

Modulates estrogen receptor activity beyond simple metabolism shift.

Cervical Dysplasia

Multiple trials show I3C supplementation helps regression of cervical dysplasia (CIN II/III).

02

What to expect

Early
Days 1–7

Days 1-14: subtle effects.

Mid
Weeks 2–4

Weeks 4-12: peak metabolism shift.

Later
Weeks 4–12

Long-term continuous use OK.

03

Evidence

HumanPresent
AnimalStrong
In-vitroPresent

Claims we could not support

No abstract we checked supports these for this molecule at this route. That is not the same as saying they are false — it marks where the evidence is missing.

Dose/route: 200-400mg daily; Oral capsule; 1-2x daily. No checked live PubMed abstract verified this exact displayed dose, route, and frequency for the same molecule/formulation and relevant population.

Mechanism: I3C and its in vivo metabolites act via: 1. Stomach Acid Polymerization: I3C is unstable in stomach acid - polymerizes to DIM and other indole compounds. DIM is the active form. 2. CYP1A1 Induction: Shifts estrogen metabolism toward 2-hydroxyestrone (less proliferative) over 16α-hydroxyestrone (more proliferative). Theoretical benefit in estrogen-driven conditions. 3. Aryl Hydrocarbon Receptor (AhR) Modulation: AhR ligand activity drives Phase 1/2 detox enzyme upregulation. 4. Anti-Estrogenic at Cellular Level: Modulates estrogen receptor activity beyond simple metabolism shift. 5. Cervical Dysplasia: Multiple trials show I3C supplementation helps regression of cervical dysplasia (CIN II/III).. No checked live PubMed abstract provided an exact-molecule/formulation sentence supporting this source-JSON mechanism claim.

Primary safety claim: No primary safety text present in source JSON. No checked live PubMed abstract directly verified this source-JSON safety claim at the displayed formulation, route, and regimen.

04

Side effects & safety

Commonly reported

  • Mild GI
  • Mild headache (rare)

Less common & notes

  • CYP enzyme induction at high doses.
  • Allergic reactions rare.
  • Long-term safety good at standard doses.
05

Pharmacokinetics

Illustrative plasma concentration · 18 h
Half-life

Polymerized DIM ~hours

Peak · Tmax
1-3 hours
Elimination

Cumulative effects over weeks

Bioavailability

Oral moderate (depends on stomach acid for conversion)

Duration of action

Daily dosing for sustained effects

Clearance

Hepatic

Storage. Capsule. Cool dry location.

06

Regulatory status

Dietary supplement (US, DSHEA).

Put it to work

Calculate, log & track

Open I3C straight into OnePin with your vial and dose pre-filled, then let it handle the syringe math and remind you before the vial runs out.

Open I3C in the app →

Go deeper

The guide & community

The complete I3C walkthrough, real protocol discussion and coaching live inside the BlessUp community on Skool.

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Open in app Community

Track it in OnePin. Log vials, draws, and protocols in the app.