Frankincense and myrrh essential oils are used primarily in three ways: diluted on the skin, diffused into the air, and incorporated into oral care products. Both oils have been the subject of growing research interest for their antimicrobial and anti-inflammatory properties, and the two appear to work better together than alone for certain applications. Getting practical benefit from them, though, depends on understanding dilution, carrier oil selection, storage, and a handful of safety issues that most casual users overlook.
What You Are Actually Working With
Frankincense essential oil comes from the oleo gum resin of trees in the genus Boswellia. The resin itself contains roughly 5 to 9 percent essential oil, with the rest being alcohol-soluble resin and water-soluble gum.1ResearchGate. Extraction of Essential Oil from Frankincense Using Steam Distillation That volatile fraction is what ends up in the bottle after steam distillation, and it is rich in monoterpene hydrocarbons, with alpha-pinene often making up a quarter to nearly half of a given sample.2PubMed Central. Comparison of Volatile Constituents Present in Commercial and Lab-Distilled Frankincense (Boswellia carteri) Essential Oils for Authentication The exact chemical profile shifts depending on the Boswellia species. An analysis of 46 commercially available gum resins and oils found 216 identifiable compounds across the four main commercial species, and those profiles were distinct enough to tell the species apart statistically.3PubMed. Frankincense Revisited, Part I: Comparative Analysis of Volatiles in Commercially Relevant Boswellia Species Across all species, more than 300 volatile compounds have been documented in the literature.4Flavour and Fragrance Journal. The volatile constituents of frankincense – a review
Myrrh essential oil, from Commiphora myrrh trees, has a different chemical personality. Its key constituents include sesquiterpenoids like curzerene and germacrene B, along with monoterpenes such as limonene.5Saudi Pharmaceutical Journal. Analysis of inorganic and organic constituents of myrrh resin by GC–MS and ICP-MS: An emphasis on medicinal assets The terpenoid profile also features diterpenoids, triterpenoids, and steroids.6PubMed Central. Commiphora myrrh: a phytochemical and pharmacological update This matters practically because the two oils bring different active compounds to the table, which is part of why combining them has attracted research attention.
Topical Use and Dilution
The most common way people use frankincense and myrrh essential oils is on the skin, and the single most important rule is to dilute them in a carrier oil first. Applying undiluted essential oils directly to skin raises the risk of irritation and contact dermatitis.7PubMed. Carrier oils in dermatology A typical starting dilution for adults is around 2 to 3 percent, which works out to roughly 12 to 18 drops of essential oil per ounce of carrier oil. For sensitive skin or facial application, dropping to 1 percent is a reasonable precaution.
Your choice of carrier oil is not just a neutral vehicle. Carrier oils can affect how the essential oil’s compounds penetrate the skin, and some carriers bring their own biological activity. Research on carrier oils combined with essential oils found that jojoba oil and aloe vera were particularly good partners: they did not interfere with antimicrobial activity, and aloe vera reduced the overall cell toxicity of the essential oil combinations by about 85 to 87 percent over 24 to 48 hours.8PubMed Central. The Influence of Carrier Oils on the Antimicrobial Activity and Cytotoxicity of Essential Oils Jojoba oil has also been shown to affect fatty acid levels after transdermal application, meaning the carrier itself is absorbed and biologically active, not just a passive diluter.9Journal of Dermatology and Skin Science. Essential Oils as Skin Permeation Boosters and Their Predicted Effect Mechanisms Other commonly used carriers include sweet almond oil, fractionated coconut oil, and argan oil. Any of these will work, but jojoba and aloe vera have the best documented track record for preserving antimicrobial benefit while improving safety.
What Topical Application Can Do
Frankincense essential oil has shown anti-inflammatory effects in lab studies on human skin cells. When tested on dermal fibroblasts, it reduced levels of two inflammatory biomarkers (IP-10 and ICAM-1), both of which play a role in skin inflammation.10PubMed Central. Biological activities of frankincense essential oil in human dermal fibroblasts In an animal wound model, a frankincense essential oil film applied to full-thickness wounds improved healing, increased collagen deposition, and lowered expression of the inflammatory marker IL-6.11Journal of Drug Delivery Science and Technology. Potential of frankincense essential oil-loaded whey protein nanoparticles embedded in frankincense resin as a wound healing film based on green technology Separate research on topical frankincense for frostbite-damaged skin found similar results, with improvements in wound healing, collagen remodeling, and reduced inflammatory markers.12PubMed. Topical frankincense treatment for frostbite based on microcirculation improvements
Myrrh essential oil leans more toward antimicrobial territory. It has demonstrated activity against a range of pathogens, and its zones of inhibition against gram-negative bacteria were comparable to those of the broad-spectrum antibiotic ciprofloxacin. Against test fungi, myrrh oil was about 79 percent as active as the antifungal drug griseofulvin.13Journal of Integrative Dermatology. Essential Oils in Dermatology – Section: Myrrh Oil In studies screening commercial essential oils against skin-relevant bacteria, myrrh showed noteworthy activity against E. coli and Pseudomonas aeruginosa.14PubMed Central. Commercial Essential Oils as Potential Antimicrobials to Treat Skin Diseases
The practical implication: if you are using these oils topically for general skin care, frankincense is the better pick for calming irritation and supporting skin repair, while myrrh is the stronger antimicrobial. Using both together covers more ground, which leads to a well-studied phenomenon.
Using Frankincense and Myrrh Together
The pairing of frankincense and myrrh is not just tradition. When researchers tested various combinations of frankincense and myrrh oils against bacteria, they found synergistic, additive, and noninteractive effects depending on the specific species combination. No antagonism was observed in any pairing, meaning the oils never interfered with each other’s activity. The most effective antimicrobial combination turned out to be Boswellia papyrifera frankincense paired with Commiphora myrrha.15Letters in Applied Microbiology. The additive and synergistic antimicrobial effects of select frankincense and myrrh oils – a combination from the pharaonic pharmacopoeia
Broader pharmacological reviews have found synergistic effects extending beyond antimicrobial activity to include anti-inflammatory, analgesic, and anticancer properties when the two resins are combined.16PubMed Central. Seeing the Unseen of the Combination of Two Natural Resins, Frankincense and Myrrh: Changes in Chemical Constituents and Pharmacological Activities For home use, this suggests that blending both oils in your carrier at a combined 2 to 3 percent dilution is a reasonable approach for a topical application targeting either skin irritation or minor cuts and scrapes. A common starting ratio is equal parts of each, though the research on optimal ratios is limited to specific bacteria and does not translate directly to a one-size-fits-all skin care recipe.
Oral and Dental Uses
Myrrh has a long history in oral care, and modern research provides some support for it. A systematic review and meta-analysis of randomized trials found that myrrh produced a small but statistically significant reduction in dental plaque, though its effects on gingival inflammation and healing did not reach statistical significance.17PubMed Central. Myrrh in the Management of Periodontal Disease and Gingival Healing: A Systematic Review and Meta-Analysis A pilot clinical study comparing a Commiphora myrrh mouthwash to chlorhexidine (the standard antimicrobial mouthwash) found that the myrrh group showed the largest reduction in gingival index scores and a significant reduction in plaque index after two weeks.18The Open Dentistry Journal. Anti-Inflammatory and Anti-Plaque Effects of Commiphora Myrrh Mouthwash: A Preliminary Pilot Clinical Study
To use myrrh essential oil for oral health at home, people typically add one to two drops to a small glass of water and swish it as a mouthwash, or add a drop to toothpaste on the brush. Frankincense is less studied in this context but is sometimes included in oil-pulling blends. The evidence is stronger for myrrh here, so if oral care is your primary goal, myrrh is the one to prioritize. Do not swallow the mixture, and keep concentrations low; these are potent compounds even in small amounts.
Diffusing and Inhalation
Both frankincense and myrrh are popular choices for ultrasonic and nebulizing diffusers. Frankincense in particular has been studied for stress-related effects. In an animal study, frankincense essential oil at a dilution of 1:1000 significantly reduced corticosterone (the rodent equivalent of cortisol) levels compared to a control. The researchers concluded that inhalation could help relieve sleep debt and maintain antioxidant capacity under stress conditions.19Journal of Oleo Science. The Effects of Frankincense Essential Oil on Stress in Rats Human data on inhaled frankincense and stress reduction is still thin, so take the animal findings as suggestive rather than proven.
If you are diffusing either oil, keep sessions to about 30 to 60 minutes in a well-ventilated room. Research on ultrasonic essential oil diffusers has found that they release volatile organic compounds and particulate matter, with the specific emission profile depending on the oil used. One study measured fine particulate matter (under 1 micrometer) emitted at rates high enough that modeling suggested they could meaningfully affect indoor air quality.20PubMed. Volatile organic compound and particulate matter emissions from an ultrasonic essential oil diffuser Running a diffuser continuously in a closed bedroom, especially while sleeping, is likely not ideal. Intermittent use with good airflow is a more sensible approach, and anyone with asthma or reactive airway disease should be cautious with any form of aerosolized essential oil.
Skin Sensitization and the Oxidation Problem
Both frankincense and myrrh contain terpene compounds that, when fresh, are relatively mild on the skin. The problem starts when those compounds oxidize. Limonene, found in both oils (particularly myrrh), and linalool, found in many essential oil blends, become increasingly irritating and allergenic as they react with air over time. Research on fragrance terpenes showed that non-oxidized versions were non-irritating at all tested concentrations, but after oxidation, both linalool and especially limonene became significantly more irritating.21PubMed. Air oxidation increases skin irritation from fragrance terpenes
Oxidized limonene in particular has been flagged as a frequent cause of allergic contact dermatitis, with enough clinical evidence to classify it as a skin sensitizer in European regulatory frameworks.22Journal of the American Academy of Dermatology. Allergic contact dermatitis from oxidized limonene Oxidized linalool is similarly problematic: patch testing across dermatitis patients found positive reactions in about 7 percent overall, with some clinics seeing rates as high as 13 percent.23PubMed. Air-oxidized linalool: a frequent cause of fragrance contact allergy
The practical takeaway is that storage matters as much as dilution. Keep your essential oils in dark glass bottles, tightly sealed, and away from heat and light. Once a bottle has been open for more than a year, the oxidation of its terpene compounds is well underway, and the risk of skin reactions goes up. If an old bottle smells noticeably different from when you bought it, or if your skin reacts to an oil it previously tolerated, oxidation is the likely culprit. Switching to a fresh bottle and testing a small patch of skin before broader use is the sensible response.
Pregnancy and Uterine Effects
Myrrh essential oil deserves specific caution during pregnancy. A clinical case report documented myrrh acting as a uterine stimulant, causing acute abdominal pain in a pregnant woman.24PubMed Central. Risks of Myrrh usage in pregnancy This uterine-stimulating property has actually been studied in a clinical context: in a randomized, double-blind trial of women with incomplete abortion, an oral myrrh preparation led to successful complete abortion in about 83 percent of participants, compared to about 54 percent in the placebo group.25PubMed Central. Efficacy and safety of myrrh in patients with incomplete abortion: a randomized, double-blind, placebo-controlled clinical study The uterine effect is real and documented, not just a folk precaution. If you are pregnant or trying to conceive, avoid myrrh essential oil entirely, whether topically, orally, or via diffusion.
Drug Interactions
This is an underappreciated risk. Frankincense extracts from all four major commercial Boswellia species have been identified as potent, non-selective inhibitors of major drug-metabolizing enzymes in the liver, including CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4.26PubMed. Analysis of frankincense from various Boswellia species with inhibitory activity on human drug metabolising cytochrome P450 enzymes using liquid chromatography mass spectrometry after automated on-line extraction Those enzyme names may not mean much to you, but collectively they are responsible for metabolizing most prescription drugs. Inhibiting them means medications could stay in your system longer and at higher concentrations than intended.
The research was conducted on resin extracts rather than the distilled essential oil specifically, and topical use at low dilutions poses less systemic risk than oral supplementation with frankincense capsules. Still, if you take prescription medications (particularly blood thinners, immunosuppressants, or drugs with narrow therapeutic windows), it is worth mentioning your use of frankincense products to your prescriber. This is especially true if you are using frankincense resin supplements orally, where systemic absorption is far higher than with a diluted topical application.
Practical Application Recipes
For a general-purpose topical blend, combine roughly 6 drops of frankincense essential oil and 6 drops of myrrh essential oil per ounce (30 mL) of jojoba oil. This lands you at approximately a 2 percent total dilution. Apply a small amount to the inner forearm and wait 24 hours before using it more broadly; this patch test catches most contact sensitivity reactions before they become a full-body problem.
For facial use or sensitive skin, halve that to 3 drops of each per ounce. For a targeted antimicrobial application on minor cuts or scrapes after cleaning the wound, you can go slightly higher, to about 3 percent total, but there is no good reason for a general user to exceed that. More is not better with essential oils; the dose-response curve for skin irritation is steep.
For diffusing, most ultrasonic diffusers call for 3 to 5 drops of essential oil per 100 mL of water. Using 2 drops of frankincense and 2 drops of myrrh gives you a balanced blend. Run the diffuser in 30-minute intervals rather than continuously, and keep a window cracked or the door open so volatile organic compounds do not accumulate. For a mouthwash, add 1 to 2 drops of myrrh oil to about 4 ounces of water, swish for 30 seconds, and spit. Do not add frankincense to oral preparations unless you have confirmed the specific product is food-grade and intended for that purpose.
Why Species and Sourcing Matter
Not all frankincense oils are interchangeable. The four commercially relevant Boswellia species (B. sacra, B. serrata, B. papyrifera, and B. frereana) produce oils with measurably different chemical profiles.3PubMed. Frankincense Revisited, Part I: Comparative Analysis of Volatiles in Commercially Relevant Boswellia Species B. sacra, from Oman and Yemen, is often marketed as the premium variety. B. serrata, from India, is the species most commonly found in supplements. B. carteri, from Somalia, dominates the essential oil market. Each has different ratios of alpha-pinene, alpha-thujene, and other terpenes, which means the anti-inflammatory and antimicrobial punch varies by species.
Adulteration is a real problem. Lab analysis of commercial frankincense oils has revealed samples where the chemical profile did not match the labeled species. Some oils labeled as B. carteri were contaminated with B. serrata, identifiable by unusually high alpha-thujene levels (up to 53 percent in one sample, compared to the normal range for carteri).2PubMed Central. Comparison of Volatile Constituents Present in Commercial and Lab-Distilled Frankincense (Boswellia carteri) Essential Oils for Authentication If you are buying frankincense essential oil for a specific purpose, look for vendors that provide gas chromatography-mass spectrometry (GC-MS) reports for each batch. These test reports are the only reliable way to verify that the species and chemical composition match what is on the label. A reputable supplier will make these available on request or post them on their website.