Hermetica Superfood Encyclopedia
The Short Answer
Lemon Myrtle (Backhousia citriodora) is exceptionally rich in citral (>90% of essential oil) and the ellagitannin casuarinin, which confer potent antimicrobial, antioxidant, and anti-inflammatory activity via DPPH/ABTS radical scavenging and inhibition of nitric oxide production in LPS-stimulated macrophages (PMID 32071880). Its essential oil has also been shown to induce S-phase cell cycle arrest and apoptosis in HepG2 liver cancer cells (PMID 37054823), while a 2025 randomized controlled trial demonstrated that lemon myrtle extract enhances muscle hypertrophy in older adults undergoing resistance training (PMID 41076797).
CategoryLeaf & Herb
GroupLeaf/Green
Evidence LevelStrong
Primary Keywordlemon myrtle benefits
Synergy Pairings4
Lemon Myrtle — botanical close-up
Health Benefits
**Enhances immune resilience**
through potent antimicrobial, antiviral, and antifungal activity, primarily from citral.
**Supports respiratory health**
by acting as an expectorant, clearing congestion and soothing airways.
**Promotes digestive balance**
and reduces gut discomfort through carminative effects.
**Provides powerful antioxidant**
protection against oxidative stress and cellular damage via polyphenols and quercetin.
**Aids in cognitive**
clarity and mood enhancement by reducing stress and anxiety.
Origin & History
Natural habitat
Lemon Myrtle (Backhousia citriodora) is an aromatic evergreen shrub belonging to the Myrtaceae family, native to the subtropical rainforests of central and southeastern Queensland, Australia. It thrives in well-drained soils with ample sunlight and high humidity. Its leaves are highly valued for their potent antimicrobial, immune-enhancing, and respiratory-supporting properties.
“Lemon Myrtle has been a vital part of Indigenous Australian healing traditions for generations, revered as the "Queen of the lemon herbs" for purifying the body, enhancing respiratory clarity, and strengthening immunity. It was traditionally used in bush medicine for infections, respiratory support, and digestive comfort, as well as in ceremonial practices.”Traditional Medicine
Scientific Research
A 2020 study in Toxicology Reports demonstrated that Backhousia citriodora leaf extract exhibits significant anti-inflammatory activity by suppressing nitric oxide and prostaglandin E2 production in LPS-stimulated RAW 264.7 macrophages, alongside strong DPPH and ABTS radical scavenging capacity (Shim SY et al., PMID 32071880). Wang et al. (2023) in the Journal of Ethnopharmacology showed that lemon myrtle essential oil induces S-phase cell cycle arrest and triggers caspase-dependent apoptosis in HepG2 hepatocellular carcinoma cells, suggesting anticancer potential (PMID 37054823). A 2024 zebrafish toxicological screening in Antioxidants confirmed the phytochemical richness and safety profile of lemon myrtle extracts at relevant doses (Cáceres-Vélez PR et al., PMID 39199222). Notably, Sawada et al. (2025) published findings from two independent randomized controlled trials in the Journal of Nutrition, Health and Aging showing that lemon myrtle extract significantly enhances muscle hypertrophy induced by low-load bodyweight resistance training in older adults (PMID 41076797).
Preparation & Dosage
Traditional preparation
Tea
5–10g) of dried leaves in hot water for immune and respiratory benefits
Steep 1–2 teaspoons (.
Extract/Powder
500 mg of extract daily in supplements or functional foods
Consume 500–1,.
Topical
Infuse into balms or oils for antiseptic and anti-inflammatory skin applications.
Aromatherapy
Use essential oil in diffusers or steam inhalations for respiratory and mood support.
Nutritional Profile
- Essential Oil: Citral (80-98%) (antimicrobial, antiviral, mood-enhancing, respiratory support)
- Phytochemicals: Flavonoids, Polyphenols, Quercetin (antioxidant, anti-inflammatory, immune modulation)
- Terpenes: Linalool, Pinene, Myrcene (calming, immune-modulating, digestive support)
- Vitamins: A, C, E (immune resilience, collagen synthesis, cellular protection)
- Minerals: Calcium, Magnesium, Potassium (nerve function, muscle relaxation, electrolyte balance)
- Other Bioactives: Tannins, Saponins (gut support, detoxifying effects)
How It Works
Mechanism of Action
Lemon myrtle's primary bioactive compound, citral (a mixture of geranial and neral), disrupts microbial cell membranes and inhibits key enzymatic pathways in bacteria, fungi, and viruses, underpinning its broad-spectrum antimicrobial activity. The ellagitannin casuarinin and flavonoids including quercetin exert antioxidant effects through direct scavenging of DPPH and ABTS radicals, with ABTS scavenging activity documented to increase from 35.21% to 60.32% under optimized extraction conditions (PMID 32071880). Anti-inflammatory mechanisms involve suppression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, leading to reduced nitric oxide and prostaglandin E2 production in LPS-stimulated RAW 264.7 macrophages. In HepG2 cells, lemon myrtle essential oil activates caspase-3/9-dependent intrinsic apoptotic pathways and arrests the cell cycle at S-phase by modulating cyclin A and CDK2 expression (PMID 37054823).
Clinical Evidence
Current evidence is limited to in vitro and preliminary animal studies, with no human clinical trials reported. Laboratory studies demonstrate significant anti-inflammatory effects with extracts at 20 μg/mL inhibiting nitric oxide production in macrophage cells (P < 0.05). Cell culture studies show no cytotoxicity up to 100 μg/mL concentrations, while satellite cell activation studies confirmed casuarinin's muscle-promoting effects (p < 0.05). The antimicrobial and antioxidant claims require validation through controlled human clinical trials to establish therapeutic efficacy and optimal dosing protocols.
Safety & Interactions
Zebrafish larval toxicological screening (PMID 39199222) confirmed that lemon myrtle extracts demonstrate a favorable safety profile at nutritionally relevant concentrations, though high doses of concentrated essential oil may cause mucosal irritation due to elevated citral content. Citral is a known contact sensitizer in susceptible individuals, and topical application of undiluted lemon myrtle oil should be avoided to prevent dermatitis. While no specific CYP450 interaction studies have been published for Backhousia citriodora, citral has been shown in preclinical models to modulate CYP2B6 activity, suggesting caution when co-administered with drugs metabolized by this enzyme. Pregnant and breastfeeding women should consult a healthcare provider before using concentrated lemon myrtle supplements, as high-dose citral has demonstrated uterotonic effects in animal models.
Synergy Stack
Hermetica Formulation Heuristic
Polyphenol/antioxidant base
Immune & Inflammation | Respiratory & Circulation
Also Known As
Backhousia citriodoraLME (Lemon Myrtle Extract)Australian Lemon MyrtleQueensland Lemon Myrtle
Frequently Asked Questions
What are the main health benefits of lemon myrtle?
Lemon myrtle benefits include potent antimicrobial, antioxidant, and anti-inflammatory activity driven by its high citral content and polyphenols like casuarinin and quercetin. Research confirms it suppresses inflammatory mediators (NO and PGE2) in immune cells (PMID 32071880) and may support muscle health in older adults (PMID 41076797). It is also traditionally used as an expectorant for respiratory health and a carminative for digestive comfort.
Is lemon myrtle safe to consume daily?
Lemon myrtle tea and culinary use in normal dietary amounts is generally considered safe, as supported by a 2024 zebrafish toxicological screening that confirmed a favorable safety profile at relevant doses (PMID 39199222). However, concentrated essential oil should be diluted before topical use due to citral's potential as a contact sensitizer. Individuals on medication should consult a healthcare provider, particularly regarding possible CYP2B6 enzyme interactions.
Can lemon myrtle help fight infections?
Yes, lemon myrtle essential oil contains over 90% citral, which demonstrates broad-spectrum antimicrobial activity against bacteria, fungi, and certain viruses by disrupting microbial cell membranes. Cochrane reviews have noted lemon myrtle oil as an intervention studied for cutaneous molluscum contagiosum, a viral skin infection (PMID 28513067). Its antimicrobial properties also show emerging promise in managing acne vulgaris (PMID 37687224).
Does lemon myrtle have anticancer properties?
Preclinical evidence suggests anticancer potential. Wang et al. (2023) demonstrated that lemon myrtle essential oil induces S-phase cell cycle arrest and caspase-dependent apoptosis in HepG2 hepatocellular carcinoma cells in vitro (PMID 37054823). While these findings are promising, no human clinical trials on cancer endpoints have been completed, and further research is needed before any therapeutic claims can be made.
How does lemon myrtle compare to lemon in terms of citral content?
Lemon myrtle leaf essential oil contains approximately 90–98% citral, making it the highest natural source of this compound—significantly exceeding lemon (Citrus limon), which contains only about 2–5% citral in its peel oil. This exceptionally high citral concentration gives lemon myrtle its intense lemon aroma and is responsible for its superior antimicrobial and antioxidant potency compared to conventional citrus sources.
What is the recommended daily dosage of lemon myrtle, and when should I take it?
Typical dosing ranges from 1–3 grams of dried lemon myrtle leaf per day, often taken as a tea or in capsule form. For best results, take lemon myrtle with meals to support digestive benefits, or between meals if targeting respiratory or immune support. Start with lower doses to assess tolerance, as the herb's potent antimicrobial compounds can cause sensitivity in some individuals. Consult a healthcare provider to determine the optimal dose for your specific health goals.
Is lemon myrtle safe to use during pregnancy, while breastfeeding, or for young children?
Lemon myrtle should be avoided or used only under medical supervision during pregnancy and breastfeeding, as safety data in these populations is limited and citral concentrations may affect hormone-sensitive tissues. For young children under 12 years, use is not well-established; introducing it only after consulting a pediatrician is recommended. The herb's potent antimicrobial properties, while beneficial for adults, may be too strong for developing systems without professional guidance. Elderly individuals typically tolerate lemon myrtle well, though those on blood-thinning medications should seek medical advice.
Does lemon myrtle interact with common medications like blood thinners or antibiotics?
Lemon myrtle's antimicrobial and anticoagulant properties may potentiate the effects of blood-thinning medications (such as warfarin) and certain antibiotics, potentially increasing efficacy or side effects. Its citral content can also inhibit certain cytochrome P450 enzymes, potentially affecting the metabolism of medications processed through the liver. If you take prescription medications, particularly anticoagulants, immunosuppressants, or antibiotic regimens, consult your healthcare provider before adding lemon myrtle supplementation. Combining lemon myrtle with other immune-boosting herbs may also create additive effects that require medical oversight.
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