Ylang Ylang (Cananga odorata): A Comprehensive Reference
1. Identity: Botanical Classification, Names, and Forms
1.1 Botanical and Scientific Identity
Cananga odorata Hook. F. & Thomson is one of the plants exploited at a large scale for its essential oil, which is an important raw material for the fragrance industry. Commonly called ylang ylang, it is a tropical evergreen tree of the family Annonaceae that produces fragrant flowers and is widely cultivated throughout Southeast Asia. The species name odorata refers to its characteristic fragrance. Synonyms recorded in the literature include Canangium odoratum (Lam.) Baill. ex King and Unona odorata (Lam.), among several others reflecting historical reclassifications.
The name "ylang-ylang" is derived from the Malay word "alang-ylang," meaning "flower within a flower." An alternative etymology traces the name to the Tagalog word "ilang," meaning "wild," or from "ilang-ilan," meaning "uncommon," perhaps referring to its intense and unique fragrance.
1.2 Natural Source and Varieties
The plant is natively found in tropical Asia such as Philippines, Malaysia, Indonesia, and some other islands of the Indian Ocean, mainly the Comoro, Nossi Be, and Madagascar islands. The plant has been well-known for its fragrant flower and has been introduced to China, India, Africa, and America.
C. odorata var. fruticosa, or dwarf ylang ylang, is another variety that is popularly grown in Southeast Asia as a small, compact shrub with highly scented flowers. Its essential oil is also used in the perfume industry. The variation in chemical profile between these botanical varieties and between growing regions is well documented. The differences in chemical composition of essential oils may be due to differences in genetic background, geographic location, growth conditions, and extraction methods. For example, Madagascar ylang ylang is described as sunny and airy, whereas Comoro is heady, floral, and slightly smoky.
1.3 Commercial Forms and Grades
Primarily, the ylang ylang essential oil is derived from the flower of the C. odorata plant via water or water and steam distillation. The commercial trade recognizes a graded distillation system: steam-distilled from 100 kg of fresh ylang ylang flowers over approximately 20 hours, the essential oil is classified into four grades based on the distillation process. There are different "pressings" of ylang ylang oil, called "extra" and then 1st, 2nd, and 3rd pressing. The extra is the very first pressing and contains the highest amounts of esters and therefore has the sweetest odor, while the later pressings have a less-sweet odor. Complete is a mixture of all grades from Extra to Third, and is said to have a varying fragrance depending on the manufacturer and the year of distillation.
The chemical constituents that make up ylang ylang essential oil have only been imperfectly defined from a quantitative standpoint, but some reports indicate methyl benzoate, 4-methylanisole, benzyl benzoate, linalool, and dehydrodi-isoeugenol to be present in significant amounts. Ylang ylang oil has been in public use since the 1880s. It is approved as a food additive by the FDA and has been determined to be GRAS by FEMA.
Beyond essential oil, the flower is also used in whole or macerated form. Essential oils obtained by steam distillation from mature fresh ylang ylang flowers are used in the cosmetic industry as major components of perfumes and fragrances, in the food industry as ingredients of aromas and flavours, and in the pharmaceutical industry as active components of antibacterials and in aromatherapy.
2. Traditional and Historical Use
2.1 Southeast Asian Indigenous Traditions
Traditionally, C. odorata is used to treat malaria, stomach ailments, asthma, gout, and rheumatism. These uses are reported across its native range, including the Philippines, Indonesia, and Malaysia.
The use of ylang ylang essential oil dates back to ancient Indonesia, where early inhabitants used it to add volume and shine to their hair. Remarkably, this oil was one of the earliest hairstyling products known to history. Indigenous people in the Philippines utilized ylang ylang to create ointments for treating minor cuts and burns. On other South Pacific islands, it was the main ingredient in Makassar Oil, a popular Victorian-era hair tonic in England.
In the Philippines, bunches of ylang ylang blooms are offered at churches as a fragrant expression of devotion and spirituality. In Polynesia, the flowers are used to make fragrant leis and are infused into coconut oil for skin and hair. In Tonga, the tree is called Mohokoi, where the bark is combined with erythrina bark (ngatae) to create a soothing infusion for abdominal ailments.
Ylang ylang has been used in traditional medicine and spiritual rituals for centuries, particularly in Indonesia and the Philippines. In Indonesia, ylang ylang flowers are often spread on the beds of newlyweds as a symbol of love and fertility.
2.2 Introduction to Europe and Modern Perfumery
In the late 19th century, ylang ylang gained significant attention in Europe after its introduction to France, where it became an essential ingredient in perfumes. Its rich, exotic scent led to its inclusion in some of the world's most famous fragrances. In 1860, Albertus Schwenger, a German sailor, set up the first distillation unit to derive its essence in Manila. During the period from 1860 to 1950, the Philippines enjoyed a golden age of oil production for around 50 years.
2.3 Aromatherapeutic Tradition
The essential oil, or ylang ylang oil, is used in aromatherapy and is believed to be effective in treating depression, high blood pressure, and anxiety. Within the Ayurvedic tradition, the oil has been ascribed calming, cooling, uplifting, and moisturizing properties, though this represents traditional attribution rather than established clinical evidence.
3. Key Constituents and Chemical Composition
3.1 Major Chemical Classes
A wide range of chemical compounds including monoterpenes, sesquiterpenes, and phenylpropanoids have been isolated from this plant. The essential oil is notably complex in its composition. Researchers have identified over 160 individual chemical compounds in the oil, far more than most synthetic fragrances contain.
The oil is broadly divided into an oxygenated fraction and a hydrocarbon fraction. The main components identified from the oxygenated fraction of ylang ylang essential oil include p-methylanisole, methyl benzoate, benzyl benzoate, benzyl acetate, geranyl acetate, cinnamyl acetate, (E,E)-farnesyl acetate, linalool, geraniol, and benzyl salicylate. Linalool was shown to be the main component present in the oxygenated fraction (28%) and is responsible for the floral smell of ylang ylang.
The hydrocarbon fraction of ylang ylang oil consists mainly of sesquiterpenes and monoterpenes, whereby both germacrene D and β-caryophyllene represented 63% of the total hydrocarbon fraction. γ-Muurolene and (E,E)-farnesyl acetate were both sesquiterpenes identified for the first time in ylang ylang oil in an earlier study.
3.2 Quantitative Profile from Representative Studies
A gas chromatography–mass spectrometry (GC-MS) study of ylang ylang essential oil from flowers harvested in Grande Comore identified the following major components: benzyl acetate (18.21%), linalool (15.23%), benzyl benzoate (11.39%), geranyl acetate (9.46%), methyl benzoate (7.64%), p-methyl anisole (7.38%), trans-caryophyllene (5.42%), germacrene D (4.61%), and benzyl salicylate (4.47%).
An earlier study of Colombian ylang ylang using steam distillation found the main constituents to be linalool (20.7%), germacrene-D (10.1%), benzyl benzoate (14.1%), benzyl acetate (9.6%), caryophyllene (3.1%), and p-methylanisole (6.8%). Quantitative differences across studies reflect the influence of geographic origin, harvest time, and extraction method.
In the dwarf variety (C. odorata var. fruticosa) studied in Singapore, a dominance of α-farnesene (31.50%) and α-bergamotene (26.79%) was found, with α-farnesene absent from Madagascar ylang ylang. This underscores the importance of variety and provenance in characterizing any specific ylang ylang oil.
3.3 Bioactive Molecule Summary
The constituents such as O-methylmoschatoline, liriodenine, 3,4-dihydroxybenzoic acid, germacrene D, and β-caryophyllene have been recognized as bioactive molecules that possess antimicrobial activities. Linalool is another compound that has been shown to exhibit insecticidal and anti-inflammatory activities.
All qualities of the ylang ylang oil contain the following components in varying ratios: d-α-pinene, l-linalool, geraniol, benzyl alcohol and esters, p-cresol, p-cresyl acetate, eugenol, methyl benzoate, methyl salicylate, and several acids (formic, valeric, acetic, benzoic, salicylic).
4. Scientific Evidence by Area of Use
4.1 Cardiovascular Effects: Blood Pressure and Heart Rate
This is one of the better-studied areas of ylang ylang's physiological effects in humans, though the evidence remains preliminary.
A clinical study by Hongratanaworakit and Buchbauer (2006) investigated transdermal absorption. The aim was to investigate the effects of ylang ylang oil on human physiological parameters and self-evaluation after transdermal absorption. Forty healthy volunteers participated. Physiological parameters recorded were skin temperature, pulse rate, breathing rate, and blood pressure. Self-evaluation was assessed by means of visual analog scales (VAS). The ylang ylang oil caused a significant decrease of blood pressure and a significant increase of skin temperature. At the behavioral level, subjects in the ylang ylang oil group rated themselves more calm and more relaxed than subjects in the control group. These results provide some evidence for the usage of ylang ylang oil in aromatherapy such as causing a relief of depression and stress in humans.
A randomized controlled trial by Jung et al. (2013) on healthy men examined inhalation of ylang ylang aroma (YYA). The results demonstrated that inhalation of YYA significantly decreased systolic and diastolic blood pressure. Inhalation of YYA also significantly decreased heart rates in 10 leads, except in lead I and aVR.
A further study examined a blend of lavender, ylang ylang, and bergamot. There were 52 subjects divided into an essential oil group, placebo group, and control group by random assignment. The application of aromatherapy was inhalation of blended oils with lavender, ylang ylang, and bergamot once daily for 4 weeks. Blood pressure and pulse were measured twice a week and serum cortisol levels, catecholamine levels, subjective stress, and state anxiety were measured before and after treatment. The blood pressure, pulse, subjective stress, state anxiety, and serum cortisol levels among the three groups were significantly statistically different. Differences in catecholamine among the three groups were not significant statistically. However, this study used a multi-component blend, making it impossible to attribute effects to ylang ylang alone.
A phase I/II clinical trial assessed a sticker pad releasing a combination of lavender and ylang ylang oil in high blood pressure volunteers. The safety of the pad was investigated in healthy volunteers (clinical trial phase I). The results showed there were no significant adverse reactions of the respiratory tract, skin, gastrointestinal tract, eye, or central nervous system, and the pad did not induce any irritation or blood pressure change in healthy volunteers.
Evidence assessment: The human trials in this area are small (typically fewer than 60 participants), short-term, and several use combination products rather than ylang ylang alone. Blinding is difficult to achieve in aroma studies. Evidence is therefore characterized as preliminary and exploratory; results are consistent in direction but not sufficient to support clinical recommendations.
4.2 Anxiolytic and Psychological Effects
A pilot study involving 34 nurses explored ylang ylang for anxiety and self-esteem. The aim was to verify whether use of ylang ylang essential oil by cutaneous application or inhalation alters anxiety and self-esteem perception and physiological parameters including blood pressure and temperature. A pilot study with 34 nursing professionals was randomized into three groups: cutaneous application, inhalation, and a placebo (ylang ylang essence cutaneous). Assessment was by Anxiety Inventory (IDATE) and the Dela Coleta self-esteem scale at baseline, after 30, 60, and 90 days, and at 15-day follow-up. In the pre- and post-intervention intergroup analysis, there was a significant difference in self-esteem for all three groups. There were no differences in the analysis between groups for anxiety or for physiological parameters.
A 2023 randomized controlled trial assessed ylang ylang aromatherapy specifically in patients facing a high-anxiety medical context. Hospitalization and the unfamiliar experiences of patients in interventional radiology procedures cause moderate to high levels of anxiety. The study was aimed to evaluate the anxiolytic effect of Cananga odorata essential oil aromatherapy in unexperienced patients hospitalized for interventional neuroradiology (INR) procedures. Forty-four patients admitted for their first INR procedure were randomly divided into COE and placebo control groups. The oil was demonstrated to exhibit an anxiolytic effect in animal models and had a sedative effect on healthy volunteers, though the scientific evidence of aromatherapy with COE on the reduction of anxiety remains limited.
A pediatric dental anxiety study compared ylang ylang, lavender, and placebo in 60 children aged 6–10. Sixty children were randomly assigned to one of three groups: ylang ylang, lavender, or a placebo control, with anxiety measured by pulse rate and the Frankl Behaviour Rating Scale. Both aromatherapy groups showed a significant reduction in anxiety compared to the placebo, and ylang ylang specifically led to the greatest physiological calming effect as indicated by a larger decrease in pulse rate. Aromatherapy with either essential oil is a safe and effective non-pharmacological method for managing paediatric dental anxiety.
At the preclinical level, ICR mice were subjected to three anxiety models including open field, elevated plus maze and light-dark box tests after acute and chronic YYO exposure. Main constituents of YYO were defined using GC/MS. These compounds were then tested on the male mice separately on three anxiety models. The monoamine neurotransmitters and their metabolites were analyzed after acute odor exposure and elevated plus maze test. YYO exposure only showed significant anxiolytic effect on the male mice. YYO and the three main constituents (benzyl benzoate, linalool, and benzyl alcohol) increased the time that mice visited the open arms and a lightbox area in the elevated plus-maze and light-dark box tests after acute and chronic YYO exposures. YYO and its major constituent benzyl benzoate might act on the serotonergic and dopaminergic pathways.
Evidence assessment: Human evidence consists of small, mostly unblinded pilot trials with heterogeneous populations and outcomes. Animal studies consistently point to anxiolytic activity and involvement of monoamine neurotransmitter pathways. Overall human evidence is weak to moderate and no large RCT has confirmed therapeutic efficacy for any anxiety disorder as a standalone intervention.
4.3 Cognitive Performance and Mood Modulation
A controlled human study by Moss et al. (2008), published in the International Journal of Neuroscience, specifically examined cognitive and mood effects of ylang ylang aroma. This study provides evidence for the impact of the aromas of plant essential oils on aspects of cognition and mood in healthy participants. One hundred and forty-four volunteers were randomly assigned to conditions of ylang ylang aroma, peppermint aroma, or no aroma control. Cognitive performance was assessed using the Cognitive Drug Research computerized assessment battery, with mood scales completed before and after cognitive testing. Peppermint was found to enhance memory whereas ylang ylang impaired it and lengthened processing speed. In terms of subjective mood, peppermint increased alertness and ylang ylang decreased it, but significantly increased calmness. These results provide support for the contention that the aromas of essential oils can produce significant and idiosyncratic effects on both subjective and objective assessments of aspects of human behavior.
A subsequent study investigating brainwave activity referenced the same work and noted that ylang ylang aroma might not affect information processing resources in patients with temporal lobe epilepsy, while information processing resources could be preserved under the aroma in healthy subjects.
Evidence assessment: The Moss et al. (2008) study is the principal human controlled trial in this area. Its finding that ylang ylang impaired memory performance while increasing calmness is an important pharmacological observation suggesting a trade-off between sedation and cognitive function. Evidence in this domain is based on a single adequately powered human study and several smaller investigations.
4.4 Antimicrobial Activity
Studies have shown that ylang ylang essential oil exhibits antimicrobial activity against various microorganisms, including bacteria like Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, as well as fungi such as Candida albicans and Aspergillus niger. The antimicrobial properties of the oil are primarily due to its ability to disrupt microbial cell membranes, inhibit the synthesis of essential enzymes and proteins, and interfere with microbial biofilm formation.
Quantitative in vitro testing showed that the antimicrobial activity of the essential oil of C. odorata showed a high inhibitory effect with MIC90% values at 0.23 mg/mL against S. aureus ATCC 25923 and clinical strains of S. aureus. However, both E. coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 showed high resistance towards the essential oils of C. odorata, which did not show inhibitory capacity up to the maximum concentration (27.12 mg/mL) tested.
The antimicrobial activity is enhanced by synergistic combinations. A study has proven that combinations of ylang ylang oil and thyme oil were significantly more effective against S. aureus ATCC 25923, with a synergistic effect observed in which the inhibition zone was increased by 38.4% compared to thyme oil alone. However, a slight antagonism effect was observed when ylang ylang oil was used together with thyme oil against Escherichia coli ATCC 25922, with the inhibition zone reduced by 48.9% when compared to thyme oil alone.
In vitro work examining multidrug-resistant pathogens found that the antimicrobial activity of ylang ylang essential oil was screened against twelve multidrug-resistant pathogens. The oil was effective up to 536 ÎĽg/mL, with the highest inhibition zone in the case of S. aureus MMCC21 and Escherichia coli MMCC24. The least effect was on both Bacillus cereus MMCC11 and Klebsiella pneumoniae MMCC16.
Overall, ylang ylang oil and different extracts of C. odorata show better antibacterial activities against Gram-positive bacteria than Gram-negative bacteria. S. aureus showed high susceptibility to the essential oils and extracts of C. odorata as compared to other tested Gram-negative bacteria.
Regarding the proposed mechanism of antifungal action: the antifungal mode of action involving cytoplasmic membrane lesions caused by the disruption of sterol biosynthesis was documented in Candida, Aspergillus flavus, and Botrytis cinerea cells.
Evidence assessment: All evidence is in vitro (laboratory-based) or animal; no human clinical trials have tested ylang ylang as an antimicrobial therapeutic agent. Evidence is mechanistically plausible but cannot be translated to clinical use without further research.
4.5 Anti-Inflammatory Activity
A 2022 peer-reviewed study in PMC evaluated the anti-inflammatory properties of ylang ylang essential oil in preclinical models. For in vitro tests, YEO was assessed using cytotoxicity, neutrophil chemotaxis induced by N-formyl methionyl leucyl phenylalanine (fMLP), and phagocytic activity tests. YEO was orally administered in zymosan-induced peritonitis, carrageenan-induced leukocyte rolling and adhesion events in the in situ microcirculation model, and in carrageenan-induced paw edema models. YEO did not present in vitro cytotoxicity. YEO reduced in vitro neutrophil chemotaxis induced by fMLP and reduced phagocytic activity. Oral treatment with YEO reduced leukocyte recruitment and nitric oxide production in the zymosan-induced peritonitis model, reduced rolling and adherent leukocyte number induced by carrageenan in the in situ microcirculation model, and reduced carrageenan-induced edema and mechanical hyperalgesia. YEO did not present signs of toxicity in the acute toxicity test. In conclusion, YEO affected leukocyte activation and presented antiedematogenic, anti-hyperalgesic, and anti-inflammatory properties.
Evidence assessment: Anti-inflammatory data are preclinical (in vitro and rodent models). No human clinical studies have investigated ylang ylang as an anti-inflammatory intervention.
4.6 Antioxidant Activity
Gas chromatographic analysis of ylang ylang oil identified a complex mixture of compounds, including linalool, geranyl acetate, and benzyl benzoate. Antioxidant activity was assessed using DPPH, FRAP, TAC, and beta-carotene bleaching inhibition assays, revealing significant radical scavenging capabilities, with DPPH IC50 varying between 1.57 and 3.5 mg/mL. Ylang ylang extracts and essential oil have demonstrated antioxidant activities, among other bioactivities, in laboratory settings. All antioxidant evidence is in vitro; clinical relevance has not been established.
4.7 Additional Preclinical Bioactivities
Besides antimicrobial and anti-inflammatory activities, it has been experimentally proven that C. odorata also possesses antibiofilm, antioxidant, antidiabetic, antifertility, antimelanogenesis, insect-repellent, antihyperglycemic, sedative, and relaxing properties. All of these activities are supported by laboratory or animal evidence only; none has been confirmed in adequately powered human clinical trials.
Ylang ylang extracts and essential oil have also demonstrated antiviral activities in experimental settings, though this also remains at a preclinical stage.
5. Mechanisms of Action
5.1 Central Nervous System Pathways
YYO and the three main constituents — benzyl benzoate, linalool, and benzyl alcohol — increased the time that mice visited the open arms and a lightbox area in the elevated plus-maze and light-dark box tests. YYO and its major constituent benzyl benzoate might act on the serotonergic and dopaminergic pathways.
The compound linalool, one of the major constituents, has been implicated in GABAergic modulation in broader essential oil research; specifically, compounds including benzyl acetate are believed to interact with the gamma-aminobutyric acid (GABA) neurotransmitter system, contributing to calming effects.
5.2 Autonomic Nervous System and Cardiovascular Effects
The hypotensive and bradycardic effects observed in human subjects following inhalation or transdermal application are believed to be mediated via the autonomic nervous system. Inhalation of volatile compounds may activate olfactory pathways with downstream effects on the autonomic nervous system, producing the observed reductions in blood pressure and heart rate. The precise molecular mechanism linking odorant receptor activation to autonomic cardiovascular responses remains incompletely characterized.
5.3 Antimicrobial Mechanisms
The antimicrobial properties of the oil are primarily due to its ability to disrupt microbial cell membranes, inhibit the synthesis of essential enzymes and proteins, and interfere with microbial biofilm formation. For antifungal effects, linalool treatment effectively inhibited bacterial growth, with complete destruction of the cell wall and membrane structure and function, promoting the leakage of intracellular substances and dysfunction of energy and metabolism.
6. Body Systems and Health Areas
- Cardiovascular system: Reduction of systolic and diastolic blood pressure and heart rate have been demonstrated in multiple small human trials following inhalation and transdermal application.
- Central nervous system / mood: Sedative and anxiolytic effects demonstrated in preclinical animal models; preliminary human studies show increased calmness but impaired memory and processing speed.
- Immune / inflammatory system: Anti-inflammatory and antiedematogenic activity demonstrated in rodent models via modulation of neutrophil chemotaxis, leukocyte recruitment, and nitric oxide production.
- Dermatology / skin: Active compounds (linalool, geraniol, eugenol, caryophyllene, benzyl acetate, α-farnesene, benzyl benzoate, β-amyrin, germacrene D) contribute to aromatic qualities and biological activities, including antimicrobial effects, suggesting potential applications in skin infection management at a preclinical stage.
- Antimicrobial / anti-infective: Broad-spectrum in vitro antimicrobial activity against Gram-positive bacteria, selected Gram-negative organisms, and fungi; greater potency observed against Gram-positive species.
- Traditional / gastrointestinal and respiratory: Traditionally used for malaria, stomach ailments, asthma, gout, and rheumatism, though none of these traditional indications has been evaluated in human clinical trials.
7. Dosage Forms and Reported Dosages
Ylang ylang does not have a standardized therapeutic dose established by any regulatory body. The following dosage forms and amounts have been specifically reported in published studies:
- Inhalation (aromatherapy): Jung et al. (2013) used inhalation of ylang ylang aroma under controlled conditions to examine cardiovascular effects in healthy men. The specific concentration was not separately published in available abstracts. Another blended-oil study used the inhalation method of blending oils with lavender, ylang ylang, and bergamot once daily for 4 weeks.
- Transdermal (massage / topical): The Hongratanaworakit and Buchbauer (2006) study investigated the effects of ylang ylang oil after transdermal absorption in 40 healthy volunteers. No specific percentage dilution was reported in publicly available summaries.
- Combined lavender/ylang ylang patch: The safety of sticker pads containing lavender and ylang ylang oil in healthy volunteers (clinical phase I) and the efficacy in high blood pressure volunteers (clinical phase II) were assessed.
- Preclinical oral acute toxicity: YEO at 2000 mg/kg was tested in an acute toxicity test in Swiss mice, and no signs of toxicity were observed at this dose in the animal model.
- Food flavoring: Ylang ylang oil has a long history of fragrance and food flavoring use, with no indication that its estimated consumption from food flavoring use (0.0001 mg/kg/day) has led to any adverse human health effects.
8. Safety Considerations
8.1 Regulatory Status
Ylang ylang oil has been approved to be Generally Recognized as Safe (GRAS) by the Flavor and Extract Manufacturers Association. It is approved as a food additive by the FDA. At the current level of intake as a food ingredient, estimated at 0.0001 mg/kg/day, ylang ylang oil does not pose a health risk to humans.
8.2 Dermal Sensitization and Allergic Contact Dermatitis
Skin sensitization is the most clinically significant and well-documented safety concern with ylang ylang essential oil.
Ylang ylang oil has been reported to cause dermal sensitization reactions in animals and humans, but it is unclear what constituent(s) within the essential oil comprise the offending agent(s) and whether some ylang ylang oils that have had certain constituents removed are any less prone to cause such allergic reactions. There is no indication in the literature that food exposure to ylang ylang oil has caused allergic reactions.
A large German retrospective dataset (IVDK, 2010–2019) examining 10,930 dermatitis patients found that 908 (8.3%) reacted to at least one essential oil. Among six essential oils eliciting more than 1% positive patch test reactions, ylang ylang (I + II) oil had the highest rate at 3.9%. Concomitant reactions among essential oils or between essential oils and fragrances were frequent. Among essential-oil-positive patients, women, leg dermatitis patients, patients aged 40 years or more, masseurs, and cosmeticians were over-represented.
There are multiple cases of ylang ylang oil–induced contact dermatitis and resultant hyperpigmentation. Sensitivity to ylang ylang essential oil determined via patch testing was shown to be the highest in comparison to all other essential oils tested. The Scientific Community on Consumer Safety found ylang ylang oil to be a contact allergen with an "alarming" prevalence of sensitization, defined by 100–1000 reported cases.
Allergic contact dermatitis (ACD) is a delayed hypersensitivity reaction (type 4) occurring 24–72 hours after exposure to an allergen. The mechanism involves recognition of the allergen by sensitized T lymphocytes releasing inflammatory cytokines. Essential oils, which are highly concentrated plant extracts, have been widely described as possible contact allergens in susceptible individuals. Common essential oils that can cause ACD include lavender, tea tree, peppermint, and ylang ylang oils.
The risk of sensitization is dose-dependent: dilution and risk are directly related. The more dilute an essential oil is, the lower the risk, and the more concentrated an essential oil is, the greater the risk.
8.3 Heat Sensitization
Ylang ylang essential oil has been shown to cause heat sensitization reactions in both humans and animals. Though ylang ylang oil was reported to cause thermal sensitization reactions in animals and humans, it is not clear which of the components of the oil cause these reactions.
8.4 Dermal Absorption and Interaction Potential
When applied to the skin, ylang ylang oil also has the potential to alter the absorption of other substances. This pharmacokinetic interaction potential, while documented, has not been characterized in detail in terms of specific drug classes or clinical magnitude.
8.5 Subchronic Inhalation Toxicity
One subchronic inhalation toxicity study, involving ylang ylang oil as part of a larger fragrance raw materials mixture, gave no indication of causing adverse effects, but the relevance to risk assessment of oral food flavoring use exposures is likely minimal. No further toxicity data for ylang ylang oil have been reported.
8.6 Occupational Exposure
Occupational allergic contact dermatitis caused by ylang ylang oil has been documented in the literature, particularly among cosmeticians, masseurs, and fragrance industry workers, as reflected in the over-representation of these professions in patch-test studies.
8.7 Cognitive Trade-Off with Sedative Use
The Moss et al. (2008) human study provides direct evidence that ylang ylang aroma, while increasing subjective calmness, simultaneously impairs memory performance and lengthens processing speed. Peppermint was found to enhance memory whereas ylang ylang impaired it and lengthened processing speed. In terms of subjective mood, ylang ylang decreased alertness, but significantly increased calmness. This finding is relevant to any application where cognitive performance is required concurrently with ylang ylang exposure (e.g., workplace diffusion).
References
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