A natural compound from watercress and other cabbage-family vegetables, formed when they are chopped or chewed. It helps the body clear harmful chemicals and switches on internal antioxidant defenses, and shifts how tobacco toxins are processed in smokers. Human proof of disease prevention or longevity is lacking; whole-food sources are better supported than high-dose isolates. (Full Review)

Protocol

Whole-Food Source

2–3 oz raw watercress

~1–2 cups daily, raw or lightly handled to preserve yield

Research Dose

~10 mg PEITC, 4×/day

Purified; a supervised research dose, not a validated consumer regimen

Timing

With meals, split 3–4×/day

Short half-life; split dosing sustains exposure and eases gastrointestinal upset

Time to effect

Detoxification

Hours–days

Rapid detox-biomarker shifts in feeding studies

Antioxidant Defense

Hours–days

Antioxidant-gene activation begins soon after intake

Long-Term Health

Months–years

Any disease or longevity effect accrues slowly and is not perceptible

Benefits

Medium: Enhanced detoxification of tobacco and environmental carcinogens; activation of the body's antioxidant and stress-defense system

Low: Anticancer / chemopreventive activity; anti-inflammatory effects; antimicrobial activity

Speculative: Longevity and healthspan extension; metabolic and cardiovascular support; neuroprotection

Contraindications

Pregnancy or breastfeeding

Untreated hypothyroidism or significant iodine deficiency

Active bladder or peptic conditions

Chemotherapy (except under specialist guidance)

Key Interactions

Anticoagulant/antiplatelet drugs (warfarin)

CYP-dependent medications (acetaminophen, chlorzoxazone)

NSAIDs and acetaminophen

N-acetylcysteine, high-dose antioxidants (vitamin C, glutathione)

Other isothiocyanates (sulforaphane, benzyl isothiocyanate)

Risk & Side Effects

Medium: Gastrointestinal irritation; pro-oxidant cytotoxicity

Low: Thyroid suppression; bladder and urinary tract irritation; alteration of drug metabolism

Speculative: Genotoxicity; interference with fertility or reproduction

Monitoring

Marker	Target	Why
TSH	1.0–2.0 mIU/L	Screens for the theoretical thyroid-suppressing effect
Free T4	1.0–1.5 ng/dL	Confirms adequate thyroid output alongside TSH
ALT	≤25 U/L (men), ≤20 U/L (women)	Detects pro-oxidant or metabolic stress on the liver
GGT	<20 U/L	Sensitive marker of oxidative stress and glutathione turnover
eGFR	>90 mL/min/1.73m²	Confirms healthy clearance of urinary metabolites
Complete blood count	Within standard reference range	Baseline safety check for high-dose or leukemia-context use

Cadence: Baseline before concentrated use; re-check thyroid and liver at ~3 months, then every 6–12 months during sustained high-dose use

Qualitative Assessment

Digestive comfort (absence of nausea or heartburn as a tolerability signal)
General energy and sense of wellbeing
Any urinary discomfort with higher doses
Consistency of dietary intake and preparation method

PEITC for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment