Nasturtium Leaf: Benefits, Dosage & Science

Q: What are the main active compounds in nasturtium leaf?

The primary bioactive compounds include glucosinolates (particularly glucotropaeolin) that break down into benzyl isothiocyanate, phenolic compounds like hydroxycinnamic acid isomers and caffeic acid, and flavonoids including quercetin and kaempferol glycosides. These compounds are responsible for the antimicrobial, antioxidant, and anti-inflammatory properties of nasturtium leaf.

Q: How effective is nasturtium leaf for respiratory conditions?

Animal studies show nasturtium leaf extract significantly increased lung antioxidant enzymes like glutathione peroxidase in allergen-induced inflammation models. The extract also modestly reduced inflammatory markers IL-1β and TNF-α expression, though these reductions were not statistically significant. Human clinical trials are needed to confirm respiratory benefits.

Q: Can nasturtium leaf cause thyroid problems?

Yes, nasturtium leaf contains high levels of glucosinolates that may have goitrogenic effects, potentially inhibiting iodine uptake and leading to hypothyroidism in susceptible individuals. People with existing thyroid conditions or iodine deficiency should avoid nasturtium leaf supplements. The specific dosage thresholds for these effects have not been established.

Q: What's the difference between nasturtium leaf and garden nasturtium?

Nasturtium leaf (Nasturtium officinale) is watercress from the Brassicaceae family, while garden nasturtium (Tropaeolum majus) is a different plant from South America. Both contain similar compounds like glucosinolates and phenolics, but watercress is the species primarily studied for medicinal properties. The terms are often confused, but they refer to distinct botanical species.

Q: How much nasturtium leaf extract was used in studies?

Animal studies used various preparations including hydroalcoholic extracts given twice weekly for 31 days in liver toxicity models, though specific dosages per kilogram body weight were not detailed in available research. In vitro antioxidant testing used concentrations up to 1000 ppm, with active fractions showing effects at IC50 values below 200 μg/mL. Human dosage recommendations cannot be established without clinical trials.

Q: Is nasturtium leaf safe to take with blood pressure or heart medications?

Nasturtium leaf contains potassium and compounds that may have mild blood pressure-lowering effects, so it should be used cautiously alongside antihypertensive or cardiac medications. Consult your healthcare provider before combining nasturtium leaf with medications like ACE inhibitors, beta-blockers, or potassium-sparing diuretics to avoid additive effects or potassium imbalances. Medical supervision is especially important if you have existing cardiovascular conditions or take multiple medications.

Q: What is the most bioavailable form of nasturtium leaf—fresh, dried, extract, or powder?

Fresh nasturtium leaf may provide the highest vitamin C content and some volatile compounds, but dried leaf and standardized extracts offer better stability and consistent dosing for supplementation. Liquid extracts or concentrated powders typically enhance bioavailability of the active isothiocyanates compared to whole dried leaf, though freshness and extraction methods significantly affect potency. For therapeutic use, standardized extracts (often dosed at 300–600 mg daily) are preferred because they deliver predictable amounts of active compounds.

Q: Who should avoid nasturtium leaf supplementation?

Pregnant and nursing women should avoid nasturtium leaf due to limited safety data and its traditional use as a stimulant herb. Individuals with kidney disease or those taking potassium-elevating medications should consult a doctor before use, as nasturtium's potassium content could be problematic. People with iodine deficiency or thyroid sensitivity should exercise caution, and those with bleeding disorders or on anticoagulants should seek medical guidance before supplementing.

Hermetica Superfood Encyclopedia

By Hermetica Editorial Team

Published March 15, 2026Last reviewed March 15, 2026Methodology · Editorial policy · Report an error

The Short Answer

Nasturtium leaf (Nasturtium officinale) contains glucosinolates that break down into benzyl isothiocyanate (BITC), demonstrating antimicrobial activity against E. coli and Salmonella through membrane disruption. The phenolic compounds, including hydroxycinnamic acid isomers and quercetin glycosides, provide antioxidant effects by boosting glutathione peroxidase, superoxide dismutase, and catalase while reducing malondialdehyde levels.

PubMed Studies

Validated Benefits

Synergy Pairings

At a Glance

CategoryLeaf & Herb

GroupLeaf/Green

Evidence LevelModerate

Primary KeywordNasturtium Leaf benefits

Synergy Pairings4

Nasturtium Leaf — botanical close-up

Health Benefits

**Enhances immune defenses**

and combats infections through high vitamin C and benzyl isothiocyanate content.

**Supports cardiovascular health**

and regulates blood pressure via potassium and antioxidants, promoting healthy circulation.

**Alleviates respiratory congestion,**

coughs, and colds, reflecting its traditional use for respiratory support.

**Supports liver detoxification**

pathways and promotes toxin elimination with glucotropaeolin and polyphenols.

**Reduces systemic inflammation**

and protects against oxidative damage due to its rich content of flavonoids and polyphenols.

**Stimulates digestion and**

balances the gut microbiome through its fiber and antimicrobial compounds.

Origin & History

Natural habitat

Nasturtium Leaf (Tropaeolum majus) is a vibrant, peppery plant native to South America, specifically Peru and Bolivia. Thriving in various environments from gardens to coastal areas, it is recognized for its unique flavor and potent functional compounds. This superfood is valued for its immune-boosting, cardiovascular, and detoxifying properties.

“Nasturtium has been revered by South American indigenous cultures, particularly in Peru and Bolivia, for promoting vitality, immune strength, and resilience. European herbalists and sailors also valued it for preventing scurvy and treating respiratory ailments. It was later celebrated in Europe for culinary uses, sometimes called "poor man's capers," bridging traditional medicine with culinary excellence.”Traditional Medicine

Scientific Research

Preliminary research, including in vitro and animal studies, suggests Nasturtium Leaf's potential for antimicrobial, anti-inflammatory, and antioxidant effects, attributed to its unique bioactive compounds. Further human clinical trials are needed to fully elucidate its therapeutic applications and optimal dosages.

Preparation & Dosage

Traditional preparation

Common forms

Fresh leaves (raw), dried powder, standardized extract.

General

Traditionally consumed raw, pickled, or powdered for culinary and medicinal purposes.

General

Modern applications include immune-boosting teas, detox blends, digestive health formulations, and culinary dishes like salads and smoothies.

Dosage

500–1000 mg standardized extract for immune, cardiovascular, and respiratory support

1–2 cups fresh leaves daily, or .

Nutritional Profile

- Vitamins: C - Minerals: Potassium, Iron, Magnesium - Phytochemicals/Bioactives: Glucotropaeolin (sulfur compounds), Flavonoids, Polyphenols, Lutein, Zeaxanthin, Benzyl isothiocyanate - Other: Dietary fiber, Omega-3 fatty acids

How It Works

Mechanism of Action

Nasturtium leaf's glucotropaeolin breaks down into benzyl isothiocyanate (BITC), which disrupts bacterial cell membranes and exhibits antimicrobial effects. The phenolic compounds, including caffeic acid and quercetin/kaempferol glycosides, scavenge free radicals and enhance antioxidant enzyme activity by increasing glutathione peroxidase, superoxide dismutase, and catalase. Additionally, 2-methoxy-4-vinylphenol inhibits PCNA and FAK/AKT phosphorylation pathways, contributing to anticancer effects through S-phase cell cycle arrest.

Clinical Evidence

Current evidence is limited to animal studies and in vitro research, with no human clinical trials reported. In rat models of lung inflammation, hydroalcoholic extract significantly increased lung glutathione peroxidase levels and showed modest increases in superoxide dismutase (p<0.05). CCl4-induced liver toxicity studies demonstrated restoration of glutathione, catalase, and SOD while decreasing malondialdehyde over 31 days of treatment. Antioxidant testing showed ethanolic extract achieved 37.99% DPPH inhibition at 1000 ppm compared to 93.75% for synthetic BHT control, with active fractions showing IC50 values below 200 μg/mL.

Safety & Interactions

Animal studies show no adverse effects and non-genotoxic profiles, though high glucosinolate content may cause goitrogenic effects that could inhibit iodine uptake and potentially lead to hypothyroidism in susceptible individuals. Isothiocyanate compounds may cause gastrointestinal irritation at high doses, though specific thresholds are not established. No documented drug interactions exist, but theoretical concerns include potentiation of anticoagulant or antidiabetic medications due to antioxidant properties. Safety during pregnancy and lactation has not been studied, and use should be avoided in individuals with existing thyroid conditions or iodine deficiency.

Synergy Stack

Hermetica Formulation Heuristic

Polyphenol/antioxidant base

Immune & Inflammation | Cardio & Circulation

Ginger (Zingiber officinale)

Also Known As

Nasturtium officinaleWatercressWater cressYellowcressBrooklime cressRorippa nasturtium-aquaticum

Frequently Asked Questions

What are the main active compounds in nasturtium leaf?

The primary bioactive compounds include glucosinolates (particularly glucotropaeolin) that break down into benzyl isothiocyanate, phenolic compounds like hydroxycinnamic acid isomers and caffeic acid, and flavonoids including quercetin and kaempferol glycosides. These compounds are responsible for the antimicrobial, antioxidant, and anti-inflammatory properties of nasturtium leaf.

How effective is nasturtium leaf for respiratory conditions?

Animal studies show nasturtium leaf extract significantly increased lung antioxidant enzymes like glutathione peroxidase in allergen-induced inflammation models. The extract also modestly reduced inflammatory markers IL-1β and TNF-α expression, though these reductions were not statistically significant. Human clinical trials are needed to confirm respiratory benefits.

Can nasturtium leaf cause thyroid problems?

Yes, nasturtium leaf contains high levels of glucosinolates that may have goitrogenic effects, potentially inhibiting iodine uptake and leading to hypothyroidism in susceptible individuals. People with existing thyroid conditions or iodine deficiency should avoid nasturtium leaf supplements. The specific dosage thresholds for these effects have not been established.

What's the difference between nasturtium leaf and garden nasturtium?

Nasturtium leaf (Nasturtium officinale) is watercress from the Brassicaceae family, while garden nasturtium (Tropaeolum majus) is a different plant from South America. Both contain similar compounds like glucosinolates and phenolics, but watercress is the species primarily studied for medicinal properties. The terms are often confused, but they refer to distinct botanical species.

How much nasturtium leaf extract was used in studies?

Animal studies used various preparations including hydroalcoholic extracts given twice weekly for 31 days in liver toxicity models, though specific dosages per kilogram body weight were not detailed in available research. In vitro antioxidant testing used concentrations up to 1000 ppm, with active fractions showing effects at IC50 values below 200 μg/mL. Human dosage recommendations cannot be established without clinical trials.

Is nasturtium leaf safe to take with blood pressure or heart medications?

Nasturtium leaf contains potassium and compounds that may have mild blood pressure-lowering effects, so it should be used cautiously alongside antihypertensive or cardiac medications. Consult your healthcare provider before combining nasturtium leaf with medications like ACE inhibitors, beta-blockers, or potassium-sparing diuretics to avoid additive effects or potassium imbalances. Medical supervision is especially important if you have existing cardiovascular conditions or take multiple medications.

What is the most bioavailable form of nasturtium leaf—fresh, dried, extract, or powder?

Fresh nasturtium leaf may provide the highest vitamin C content and some volatile compounds, but dried leaf and standardized extracts offer better stability and consistent dosing for supplementation. Liquid extracts or concentrated powders typically enhance bioavailability of the active isothiocyanates compared to whole dried leaf, though freshness and extraction methods significantly affect potency. For therapeutic use, standardized extracts (often dosed at 300–600 mg daily) are preferred because they deliver predictable amounts of active compounds.

Who should avoid nasturtium leaf supplementation?