Watercress
Solid evidence for peitc source. Not a miracle worker, but genuinely useful for the right person.
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Verdict
6/10 Promising
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Evidence
Grade B / 100+ Studies
Norans Kepals, Independent Researcher & Supplement Expert
March 1, 2026
The No-BS Summary
8 things. 60 seconds. Everything you need.
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WHAT IT DOES
A nutrient-dense cruciferous green packed with PEITC, a compound studied for cellular protection.
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DOES IT WORK?
Watercress is genuinely nutrient-dense and contains PEITC (phenethyl isothiocyanate), which has real anti-cancer research behind it. One small clinical trial showed it reduced DNA damage in smokers. More evidence than most greens used in supplement blends.
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HOW MUCH TO TAKE
500-1500mg extract or 80-100g fresh daily
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COST
Budget-friendly. $20-35/month for quality brands.
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FIRST 24 HOURS
Don't expect miracles on day one. It's building in your system.
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AFTER A FEW WEEKS
Most people notice something by week 2-3.
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SAFETY
Few things to check: may interact with blood thinners (vitamin k), thyroid concerns at very high doses. Worth mentioning to your doc.
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HOW IT FEELS
Effects vary person to person. Give it time.
2The Breakdown
Quick Answers
Dose-Response Curve
How effective is watercress at different doses? Here's what the research shows.
Effectiveness %
0
25
50
75
100
MIN 250mg
SWEET SPOT 1.0g
PLATEAU 3.0g
Dose (mg)
0-23%
Sub-therapeutic
<250mg
23-82%
Effective
250mg-1.0g
~82%
Optimal
1.0g
82%
Diminishing
>3.0g
Moderate confidenceBased on clinical data + estimates
Source: Hecht et al. 1995 PEITC trial; Gill et al. 2007 antioxidant trialBottom line: Most research uses 1.0g daily. Below 250mg, you're probably wasting money. Above 3.0g, you're not getting extra benefit.
Dosing Guide
When
As directed
How
500-1500mg extract or 80-100g fresh daily
Food
With or without food
Onset & Feel
Builds Over Time
Effects vary
Effects vary person to person. Give it time.
Cycle
As needed
How to Take It
Watercress comes in several formats. Pick what fits your lifestyle.
Capsules/Tablets
Pre-measured doses, easy to take.
✓ Convenient✓ No taste✓ Portable✗ More expensive✗ May need multiple
Powder
Mix with water or a shake.
✓ Cheapest✓ Flexible dosing✗ Needs mixing✗ Taste varies
Softgels
Oil-based for fat-soluble nutrients.
✓ Better absorption for fats✓ No taste✗ Larger pills
Pick this:
Capsules for convenience, powder for value.
Skip this:
Check for unnecessary fillers and additives.
Delivery affects convenience and cost, not usually effectiveness.
Did you know?
Many studies and counting.
Heads Up
Generally safe at recommended doses. Talk to your doc if you have concerns. Check with your doc if: May interact with blood thinners (vitamin K), Thyroid concerns at very high doses.
3Deep Dive
The Science, Simplified
For those who want the full picture
Watercress has emerging evidence.
Trust Signals
Grade B
Evidence
50+
Studies
30
Human Trials
0
Meta-analyses
👍 Strong evidence. Most claims hold up under scrutiny.
Mechanism of Action
PEITC inhibits Phase I enzymes (CYP2E1) that activate carcinogens while inducing Phase II detox enzymes. Contains lutein and zeaxanthin for eye health. High in vitamins A, C, K per calorie.
Research Summary
Scientific consensus: undefined/10.
Consensus: /10LIMITED Evidence
Origins & Manufacturing
Where does watercress come from? Let's get nerdy.
How It's Made
Manufacturing process varies by supplier.
What to Look For
✓ Third-party tested✓ GMP certified
Drug & Supplement Interactions
4For You
Is Watercress right for YOU?
Get a personalized verdict based on your health profile.
Products with Watercress
Supplements that contain this ingredient
Medical Disclaimer
This content is for informational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting any supplement regimen, especially if you have medical conditions or take medications. ARE Supplements does not endorse any specific products.