Essential Oil Research – Tea Tree Oil

Continuing my series of articles about the benefits of essential oils, this week I’m focusing on the benefits of tea tree oil, especially as it relates to breast cancer.

Melaleuca alternifolia (“MA”), the particular type of tea tree oil on which I will be focusing, is native to Australia. It has been researched since the 1920s and used by the Aboriginal people for millennia, mostly as a remedy for the skin.

MA is well known for its antiseptic, anti-inflammatory, and anti-bacterial properties. Indeed, research shows that MA is powerfully antibacterial, antiviral, antifungal, antiseptic, antiparasitic and anti-inflammatory.

But what about its anticancer properties – are there any? It has not been extensively studied, because after all, who would fund that study? Studies are expensive and frequently only carried out by pharmaceutical companies, especially if there will be a monetary gain from the information.

Here’s what I did find, and I think it’s worthy of a mention. I have added tea tree oil/Melaleuca alternifolia to my page listing the essential oils to consider: Essential Oils for Overall Health and Specific Health Problems. https://marnieclark.com/breast-health/essential-oils-for-overall-health-and-specific-health-problems/

If you look up tea tree oil online (or indeed, lavender) you’ll no doubt meet up with the warning that it may cause breast cancer. I dealt with that ugly accusation in this post a number of years ago: Are Lavender and Tea Tree Oils Safe to Use if You Have Breast Cancer https://marnieclark.com/are-lavender-and-tea-tree-essential-oils-safe-to-use-if-you-have-breast-cancer/

Research on Tea Tree Oil and Breast Cancer

A 2010 Australian study [1] investigating the effect of MA on aggressive murine (mouse) cancer cell lines (mesothelioma and melanoma) found that MA induced apoptosis and necrotic cell death.

A 2018 Brazilian in vitro (test tube) study [2] found that the phytochemicals (natural plant-based chemicals) within tea tree oil exhibited “a remarkable anti-tumor activity” (to quote the study) against MCF-7 (ER+ PR+ breast cancer cells) and 4T1 (stage IV triple negative breast cancer cells from mice). The constituents stopped the rapid growth of the cells and decreased cell viability.

A 2018 Indian in vitro study [3] with triple negative breast cancer cells found that MA did have anticancer activity against this cell line.

A 2021 study [4] performed by Australian researchers had similar findings. The in vitro study with prostate cancer and MCF-7 breast cancer cells found that the MA induced apoptosis (programmed cell death), reduced cell viability, and in higher doses initiated cell cycle arrest and autophagy (self-eating). They then tested MA on mice by injecting it directly into tumors and found that it significantly suppressed tumor progression and promoted immune cells to migrate to the area, with cytotoxic (toxic to the cancer cells) activity. They were also able to replicate the apoptosis and cell viability reduction seen in the in vitro experiments.

A 2025 Mexican study [5] examined MA, along with quercetin and rosmarinic acid from rosemary in a nanoemulsion. They tested each one individually and also the three together in a test tube study with triple negative breast cancer cells. They found that the trio exhibited “significant antiproliferative activity” and induced apoptosis.

While there clearly aren’t a lot of studies on MA – and none with actual humans that I could find – it certainly won’t hurt to utilize this beautiful oil. I use essential oils daily – I massage two different oils (for instance frankincense with lemon) into my breast tissue every single day, paired with prayer and affirmations, and after three days I change to a different pair of oils. I’ve done this ever since my diagnosis in 2004. To see a list of which oils pair nicely together, see this page: Awesome Essential Oil Combos. https://marnieclark.com/breast-health/essential-oils-for-overall-health-and-specific-health-problems/awesome-essential-oil-combos/

Disclaimer:
I am not telling you that you can cure breast cancer using essential oils. I would certainly not rely upon essential oils alone to do that job. But in combination with a holistic regimen of nutrition and other lifestyle changes, together with what conventional medicine you decide to choose, I believe that essential oils can be an extremely beneficial healing tool.

References:
[1] Induction of necrosis and cell cycle arrest in murine cancer cell lines by Melaleuca alternifolia (tea tree) oil and terpinen-4-ol – https://pubmed.ncbi.nlm.nih.gov/19680653/
[2] Tea tree oil presents in vitro antitumor activity on breast cancer cells without cytotoxic effects on fibroblasts and on peripheral blood mononuclear cells – https://pubmed.ncbi.nlm.nih.gov/29864906/
[3] Evaluation of anticancer activity of Melaleuka Alternifolia. (i. e. tea tree oil) on Breast cancer cell line (MDA MB)- An invitro study – https://ijmmtd.org/archive/volume/4/issue/3/article/8531/pdf
[4] Tea tree oil extract causes mitochondrial superoxide production and apoptosis as an anticancer agent, promoting tumor infiltrating neutrophils cytotoxic for breast cancer to induce tumor regression https://www.sciencedirect.com/science/article/pii/S0753332221005722#:~:text=Malaleuca%20Alternifolia%20concentrate%20(MAC)%20has,transmembrane%20potential%2C%20leading%20to%20apoptosis.
[5] Anti-proliferative and Pro-apoptotic Activity of a Novel Oil-in-Water Nanoemulsion Containing Tea Tree Oil, Quercetin, and Rosmarinic Acid in Breast Cancer Cells – https://link.springer.com/article/10.1007/s12668-024-01795-1