AUSTRALIAN LEMON-SCENTED TEA TREE OIL
Leptospermum petersonii
Australian Lemon Scented Tea Tree Essential Oil is a different species from Tea Tree Oil. It's rich in citral, a chemical compound that provides a fresh and uplifting aroma. This essential oil has antibacterial, anti-fungal, anti-inflammatory and antiseptic properties and is a natural head lice deterrent. Its fresh scent makes it ideal to mask the odor of Tea Tree Oil while conveying synergistic benefits.
Action on the microbiome: head lice treatment
This oil is effective against head lice, particularly when paired with Eucalyptus Oil. A randomized controlled trial showed that a blend of Lemon Scented Tea Tree Oil (0.5%) and Eucalyptus Oil (9%) was significantly more effective (p<0.0001) than a pyrethrin/piperonyl butoxide commercial preparation for curing head lice infestation, with no sensitization or irritation.15
Immune system activity
Lemon Scented Tea Tree Oil is effective against a variety of microorganisms, and it boosts the antimicrobial activity of Tea Tree Oil. One study showed that a combination of Lemon Scented and Tea Tree Oil in a 1:5 ratio, respectively, was four times more potent against S. aureus than Tea Tree Oil alone.16
It is theorized that the high citral content of Lemon Scented Tea Tree Oil helps the Tea Tree Oil to penetrate the bacteria's phospholipid cell wall.
Lemon Scented Tea Tree Oil is a potent antioxidant,17 which is important for scalp care, since oxidation releases free radicals that stimulate inflammatory processes affecting the skin.
Formulation tip
Lemon Scented Tea Tree Oil is a powerful partner to boost the efficacy of products containing Eucalyptus Oil or Tea Tree Oil.
At a 1:7 ratio, Lemon Scented Tea Tree Oil can be used to mask the herbaceous odor of classic Tea Tree with a more appealing fresh lemon scent.
AUSTRALIAN EUCALYPTUS OIL
Eucalyptus kochii
Australian Eucalyptus Oil offers therapeutic benefits for an inflamed and dry scalp, including antiseptic and anti-inflammatory properties.
Antibacterial action supports the microbiome
Eucalyptus Oil is effective against the organisms implicated in scalp folliculitis, Staph aureus and Cutibacterium acnes.18
Biochemical effects
Eucalyptus Oil improves the condition of the scalp because it contains macrocarpal A, a compound that appears to stimulate ceramide production. A 4-week study of people with seborrheic dermatitis or dandruff showed that Eucalyptus decreased scalp redness, itchiness, dryness, and scaliness, with symptoms improving from week 2.19
Immune system activity
Eucalyptus Oil may support the scalp's immune system by increasing circulation, a critical element for healthy hair and hair loss prevention.20
Formulation tip
Australian Eucalyptus Kochii Oil has a natural 1,8-cineole level of over 90% with one distillation, making it an effective ingredient for natural scalp care and anti-dandruff products – and it retains more natural aromatic characteristics beyond cineole.
MANUKA OIL
Leptospermum Scoparium
Manuka Oil kills gram-positive bacteria and fungi, even at low concentrations. Its actions make it the perfect partner to Tea Tree Oil.
Microbiome support
Manuka Oil is highly effective in haircare formulations as it can kill bacteria and fungi that cause or worsen dandruff. The secret to its efficacy is its high level of β-Triketone which means that only a small percentage of oil is needed for maximum antimicrobial efficacy – only a 0.091% concentration is needed for a 99% kill rate against S. aureus, for example.21
Manuka Oil vs dandruff-related microbials
Organism |
MIC % |
S.aureus |
0.078-0.125 |
S.capitis |
0.05 |
C.acnes |
0.055-0.07 |
S.epidermidis |
0.05-0.078 |
Malassezia furfur |
1.56 |
Sources: Plant & Food Research, Mathew et al. (2020)21 |
MIC: the lowest concentration of a substance that prevents visible in vitro growth of bacteria or fungi.
Immune support
Studies have shown that 0.1–10% Manuka Oil significantly reduced the release of TNF-α, an inflammatory mediator, so it could combat scalp irritation.22
Formulation tip
Manuka Oil and Tea Tree Oil are a dynamic duo. They're powerful antimicrobials when used individually but when used together their potency increases.
Adding a very small amount of Manuka to Tea Tree Oil will increase its activity against S. aureus by 73%, for example.23
Manuka Oil has had substantial growth in Europe and Asia in the last two years, so there is a huge potential for growth in North America.2
AUSTRALIAN SANDALWOOD SEED OIL
Sandalwood spicatum
Sandalwood Seed Oil is naturally high in ximenynic acid, a natural anti-inflammatory, which helps to increase blood circulation and promote scalp health and hair growth.
Biochemical activity supports healthy oil balance
The ximenynic acid in Sandalwood Seed Oil blocks the arachidonic LOX (and COX) inflammation pathways, which helps increase blood circulation to the skin.
It has the potential to reduce hair loss through enhanced blood flow to hair follicles, in a similar action to the hair-loss treatment minoxidil.
Immune effects
The structure of ximenynic acid is similar to enzymes that catalyze arachidonic acid and block inflammation pathways, making it useful to combat an itchy and inflamed scalp. An in-vitro study showed it to be clinically active at a 7% dilution ratio.24
Formulation tip
Sandalwood Seed Oil can be used just like any other fatty carrier oil like jojoba or argan oil. It contains no cosmetic allergens and is suitable for sensitive skin.
ADDITIONAL FORMULATION TIP
Hydrosols: Not essential oils, but essential to product success
Hydrosols are low-cost, natural and sustainable, all attributes that consumers are seeking.
They can be used as a water replacement at up to 100% in formulas and are naturally lathering and softening, which may reduce the amount of surfactant needed and potentially reduce costs.
Australian hydrosols are available in a range of aroma profiles, including Tea Tree, Lemon Myrtle, Fragonia, Sandalwood and Lavender.
Not all natural ingredients are reliable
When working with natural botanicals, it's crucial to understand that they can vary in quality and potency based on growing conditions, harvest timing, and processing methods. Brand owners and manufacturers need to collaborate with credentialed experts specializing in the practice.
"When using botanicals, it is so important to have a trustworthy source," emphasizes Dee-Ann Prather. "Product manufacturers should ensure they are womustrking with experts taking care of the plants with the proper credentials and in a sustainable way to get the long-term benefits of nature."
References:
- NielsenIQ Label Insight Trending Attributes, 3 months ending Jan 2024.
- Mintel, September 2024.
- Hammer KA et al. In vitro activities of ketoconazole, econazole, miconazole, and Melaleuca alternifolia (Tea Tree) Oil against Malassezia species. American Society for Microbiology 2000;44(2):467–469.
- Satchell AC et al. Treatment of dandruff with 5% tea tree oil shampoo. J Am Acad Dermatol 2002;47(6):852–5.
- Naldi L, Diphoorn J. Seborrhoeic dermatitis of the scalp. BMJ Clin Evid 2015;1713.
- Kostrzębska A et al. Effect of hydrogel substrate components on the stability of tetracycline hydrochloride and swelling activity against model skin sebum. Int J Mol Sci 2023;24:2678.
- Kostrzębska A, Musiał W.The Influence of increasing concentrations of AMPD on the efficacy of its penetration into a model skin sebum layer. Pharmaceutics 2020; 12:1228.
- Biju SS et al. Tea Tree Oil concentration in follicular casts after topical delivery: determination by high-performance thin layer chromatography using a perfused bovine udder model. J Pharm Sci 2005;94(2):240–5.
- Carson C, Riley T. Antimicrobial activity of the essential oil of Melaleuca alternifolia. Lett Appl Microbiol 1993; 16: 49–55.
- Carson C, Riley T. Antimicrobial activity of the major components of the essential oil of Melaleuca alternifolia. J Appl Bacteriol 1995; 78:264–269.
- Hammer K, Carson C, Riley T. In vitro activity of Melaleuca alternifolia (tea tree) oil against dermatophytes and other filamentous fungi. J Antimicrob Chemother 2002; 50: 195–199.
- Pazyar N et al. A review of applications of tea tree oil in dermatology. Int J Dermatol 2013;52(7):784-790.
- Ninomiya K et al. Suppression of inflammatory reactions by terpinen-4-ol, a main constituent of tea tree oil, in a murine model of oral candidiasis and its suppressive activity to cytokine production of macrophages in vitro. Biol Pharm Bull 2013; 36(5):838–44.
- Sakr FM et al. Preparation and evaluation of a multimodal minoxidil microemulsion versus minoxidil alone in the treatment of androgenic alopecia of mixed etiology: a pilot study. Drug Des Devel Ther 2013;7:413-23.
- Grieve KA, Barnes TM. The efficacy of Australian essential oils for the treatment of head lice infestation in children: A randomised controlled trial. Australas J Dermatol 2018;59(2):e99–e105.
- Stockley JK et al. The antimicrobial activity of cloned tea tree oils. PharmQuest Research Institute, 2011.
- Afolabi WO et al. Leptospermum petersonii as a potential natural food preservative. Molecules 2020;25(23):5487.
- Bhatt D et al. Studies on inhibitory effect of Eucalyptus Oil on sebaceous glands for the management of acne. IJNPR 2011; 2(3):345–349.
- Takagi Y et al. The efficacy of a pseudo-ceramide and eucalyptus extract containing lotion on dry scalp skin. Clin Cosmet Investig Dermatol 2018;11:141–48.
- Ishikawa J et al. Eucalyptus increases ceramide levels in keratinocytes and improves stratum corneum function. Int J Cosmet Sci 2012;34(1):17–22.
- Mathew C et al. Manuka Oil – A review of antimicrobial and other medicinal properties. Pharmaceuticals 2020;13(11):343.
- Chen CC et al. Investigations of kanuka and manuka essential oils for in vitro treatment of disease and cellular inflammation caused by infectious microorganisms. J Microbiol Immunol Infect 2016;49:104–11.
- Christoph F et al.In vitro evaluation of the antibacterial activity of β-triketones admixed to melaleuca oils. Planta Med 2001;67:768–771.
- Hettiarachchi D. Pharmaceutical Evaluation of Western Australia Sandalwood Seed Oil. University of Curtin 2014.
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