Essential oils with anticancer activity

Several essential oils contain bioactive compounds that show anticancer activity in lab and animal studies. This means there has been observed cell death, reduced proliferation and reduced tumor growth. A few compounds are repeatedly singled out in the literature and we will highlight these in the specific oils we look at below. Here are the compounds to be on the lookout for: d-limonene, eugenol, carvacrol, thymol, linalool, terpinen-4-ol, and α-pinene/incensole. The oils which we will discuss do all contain one or more of these compounds which lends the oil its anticancer properties.

Most evidence of the anticancer activity is in vitro or in animals, a few early human studies do exist, but you should always discuss any complementary therapies with your oncologist before use. Dr. Erik Zielinski, in his book “The Truth about essential oils and cancer” points out that: “Essential oils for cancer research suggests that oils can help prevent and treat cancer at the cellular level. Additionally, and oftentimes overlooked, essential oils have been shown to be exceptionally effective at managing the side effects related to cancer itself and the side effects people suffer at the hands of medical interventions.”  It is also important to note that you can safely use essential oils during your chemo treatment should you wish to go that route.

Essential oils with anticancer activity

1. Frankincense (Boswellia sacra, B. carterii, B. frereana, and B. serrata)

Main compounds: α-pinene, incensole/insensole acetate. (Note: boswellic acid is an anti-inflammatory/anticancer compound found in Frankincense resin extracts rather than the volatile essential oil; it’s often discussed with frankincense but is not a major volatile oil constituent.)

Studies show that Frankincense essential oil and Frankincense extracts have shown antiproliferative and pro-apoptotic effects in a range of cancer cell lines and some animal models. Recent work continues to explore frankincense essential oil formulations with anti-tumor activity.

In Dr. Zielinski’s book he also points out that the boswellic acids in Frankincense have been proven to be “cytotoxic to ovarian cancer cells at pharmacologically achievable concentrations. These acids are too large and heavy to be present in the essential oil which is volatile. In other words, boswellic acids are not volatile and are thus not part of the essential oil itself. He makes the point that Frankincense essential oil is effective never-the-less because studies continue to emerge that demonstrate the oil’s effectiveness on bladder, breast and skin cancers. If you choose to use Frankincense essential oil and want to ensure these boswellic acids are present, just incorporate Frankincense extract or the resin into your daily regime.

The most common and supportive use for Frankincense is via diffusion for stress relief. Add 3 drops to your diffuser – this can run day and night for constant inhalation. When it is diluted for topical application, do so with a 1–2% in a carrier oil (such as Castor oil) – use it topically you’re your chest/ abdomen for calming/ skin support. You can even rub it in regularly over the area where the cancer is presenting. It can be used as a supportive practice and always check with clinicians. Frankincense essential oil can be taken internally when diluted with a carrier oil or emulsified in honey.

2. Clove Bud (Syzygium aromaticum

Main compound: eugenol

Studies show that eugenol demonstrates cytotoxicity against multiple cancer cell lines. It can induce apoptosis via ROS and mitochondrial pathways, and has been combined with conventional agents in laboratory studies to increase cancer cell sensitivity. Most evidence is preclinical (in vitro/in vivo).

For a topical dilution, dilute in a carrier oil such as Castor or Fractionated Coconut oil and regularly rub into areas affected. Clove bud is a topical analgesic, so be aware of the numbing effect it might have on your skin. For inhalation just add a drop to your diffuser along with perhaps some Sweet Orange essential oil to support mood. This oil is safe to take internally as well. Add one drop to a capsule, fill with a carrier oil and use daily.

3. Oreganum (Origanum vulgare L.) and Thyme (Thymus vulgaris L.)

Main compounds: carvacrol and thymol (monoterpenoid phenols)

Studies show that both carvacrol and thymol have been shown to be cytotoxic to several cancer cell lines and to induce apoptosis and cell-cycle arrest; animal studies and systematic reviews identify promising antiproliferative effects.

In Dr. Zielinski’s book he points out that in a study that was published in the journal Molecules in 2010 the 10 most powerful essential oils against cancer was evaluated, in which Thyme stood out as the most beneficial against prostate, lung carcinoma and breast cancers.

It is noteworthy that Thyme is one of the top essential oils that facilitate estrogen binding. Since some types of cancers often holds receptors for estrogen and can be fed by any compound that is estrogenic, people at risk of developing cancer are often advised to avoid estrogen. This might be the very reason why Thyme is such an effective oil against cancer. It binds to the estrogen molecules and inhibits feeding of these cancer cells.

Oreganum and Thyme essential oils are both extremely potent and are usually used in aromatherapy blends or in topical applications at very low dilutions. At OilGrow we really do love these two oils – they are in our Boost blend to help boost the immune system.  They are sometimes included in targeted topical blends for localized antimicrobial/ anti-inflammatory use too. For cancer support, we would suggest getting these oils into your body alongside inhaling it regularly. Add 1 drop of each to a capsule with Fractionated Coconut Oil. Take this once a day – preferably in the mornings.

4. Citrus oils

(Grapefruit (Citrus x paradisi Macfad.), Lemon (Citrus limon (L.)Burm.F.), Sweet Orange (Citrus × sinensis (L.) Osbeck.), Lime (Citrus × aurantifolia (Christm.) Swingle.), Bergamot (Citrus bergamia Risso.)

Main compound: d-limonene (a major monoterpene in citrus oils)

We noted that d-limonene has been extensively studied for anticancer activity; mechanisms includes apoptosis induction, interference with cell signaling and membrane effects. There have been early-phase clinical investigations of limonene in breast cancer patients to examine tissue distribution and possible biological activity, and limonene is generally considered well tolerated in clinical context at tested doses.

The U.S. National Library of Medicine indicates that d-limonene is an oral supplement that contains natural cyclic monoterpenes with potential chemopreventive and antitumor activities. They indicate that it may inhibit tumor growth. One study said the following: “D-limonene has well-established chemopreventive activity against many types of cancer. Evidence from a phase I clinical trial demonstrated a partial response in a patient with breast cancer and stable disease for more than six months in three patients with colorectal cancer.”

The most common way to use it is by way of diffusion for uplifting the mood, topical (diluted) for direct skin uses, and – in clinical trials – oral limonene (as an isolated compound, not as an essential oil) has been studied under medical supervision. At OilGrow we are extremely cautious about taking essential oils orally. However, there are safe ways to do so – always refer to our Responsible Usage Guide, or speak to us directly. Citrus oils can safely be ingested when emulsified first. Add a drop to a teaspoon of honey, mix well, then add to your greentea. It has a pleasant taste and flavour.

5. Clary Sage (Salvia sclarea L.)

Main Compound: Sclareol

Dr. Zielinski mentions that there are studies that shows that Sclareol has an impact on the way that cancer cells proliferate. It literally kills cancer cells through a process known as apoptosis. Apoptosis is the programming of a cell to die or commit suicide. He mentions that this could mean that Clary Sage can be profound in the prevention and treatment of cancer. One thing to note is that this oil is considered to be estrogenic – this means it might increase estrogen in the body, so avoid this one if the cancer being treated is due to estrogen-dominance.

Clary Sage is a herb and therefore can be taken orally, always diluted or emulsified in a carrier oil first. So you can use it in a capsule alongside a carrier oil. You can emulsify it in honey and take half a teaspoon every day. Diffuse in your diffuser during the day.

6. Lavender (Lavandula angustifolia Mill.)

Main compounds: linalool and linalyl acetate

There are several studies that report that lavender oil and its main constituents suppress tumor growth in cell culture and some mouse models (for example prostate cancer models showed reduced tumor growth). Linalool itself has shown antiproliferative and pro-apoptotic effects in preclinical work. Due to Lavender’s amazing anti-oxidant and anti-inflammatory properties, it is considered a wonderful support for fighting cancer, since cancer is considered a free-radical build-up in the cells. It is considered a neuroprotector against oxidative stress which means it will assist in fighting cancer.

Lavender is commonly used for stress, sleep and diluted topical calming. As an adjunctive supportive measure for people with cancer, diffusing lavender is widely used to reduce anxiety and improve sleep — studies support its calming benefit, which can be valuable during cancer treatment. Lavender can also be diluted and regularly worked into the affected area.

7. Tea tree (Melaleuca alternifolia)

Main compound: terpinen-4-ol primarily.

Studies done on terpinen-4-ol have shown antitumor and pro-apoptotic activity in a range of cancer models (in vitro and some in vivo models, e.g., colorectal, melanoma). Again, most data are preclinical. You can use it as a topical dilution for antimicrobial uses (acne, minor fungal infections), and sometimes included in compresses or washes. Caution: tea tree oil is toxic if swallowed and can cause dermatitis in sensitive people — dilute and patch test.

8. Lemongrass (Cymbopogon citratus (DC.) Stapf.)

Main compounds: citral (a mixture of geranial and neral) and other aldehydes.

Studies show that lemongrass essential oil and citral have shown cytotoxicity in many cancer cell lines and antitumor effects in animal studies. Some studies report apoptosis induction and inhibition of tumor growth. Dr. Zielinski mentions a 2009 study of Lemongrass against 12 human cancer cell lines where it was discovered that this oil has a promising anti-cancer activity that causes loss in tumor cell viability by activating the apoptotic process.

You can use it by diffusing Lemongrass regularly in around the house. A topical in low dilution for massage blends can also regularly be used. Lemongrass is a powerful anti-biotic and can be used in a capsule or in honey. However, only use it in a cycle of 5 days used in the mornings, then rest for 2 days.

9. A note on Myrrh (Commiphora molmol Engler.) and other resin combinations

Myrrh and other resin oils have been studied alongside Frankincense in some laboratory studies; some combinations show additive effects in vitro. Resin extracts that include non-volatile constituents (like boswellic acids from frankincense resin) are chemically different from the essential oil and are sometimes the focus of clinical or preclinical work.

10. A note on Peppermint (Mentha piperita L.)  & Spearmint (Mentha spicata L.)

Dr. Zielinski mentions that a study published in the BioMed Research International Journal proved that peppermint and spearmint is effective at managing common side effects of people that suffer due to medical cancer treatment. This is especially true for vomiting, nausea and pain due to the effect of chemo. One way to use mint oils to counter these side effects is to diffuse it around the home during the day. Apply topically at the nape of the neck and over the chest. Inhaling it by adding one drop to the palm of your hand and cupping your hands over your nose is also a fast relief. Obviously these oils can also be taken orally as suggested with previous oils.

A Summary Table

Compound	Main Essential Oil Sources	Known / Proposed Anticancer Mechanisms	Common Supportive Uses (Aromatherapy / Topical)
d-Limonene	Citrus oils – Orange, Lemon, Grapefruit	• Induces apoptosis in cancer cells • Inhibits Ras and PI3K/Akt signaling (tumor growth pathways) • Reduces oxidative stress and inflammation • Clinical studies show accumulation in breast tissue and potential tumor suppression	Diffuse for mood uplift Topical (diluted) for skincare and lymph support
Eugenol	Clove, Cinnamon Leaf, Bay Leaf, Basil	• Induces apoptosis via caspase activation • Suppresses NF-κB and COX-2 (anti-inflammatory) • Scavenges free radicals (antioxidant) • Inhibits angiogenesis (VEGF downregulation) • Enhances chemo sensitivity	Diffuse for stress relief Topical in very low dilution (0.5–1%) for localized blends Strong sensitizer — always patch test
Carvacrol	Oregano, Thyme	• Induces apoptosis via mitochondrial dysfunction • Arrests cell cycle • Disrupts cancer cell membranes • Suppresses tumor-promoting genes	Diffuse for immune and respiratory support Topical (≤1%) for antimicrobial blends — avoid long-term use on skin
Thymol	Thyme, Oregano	• Promotes apoptosis • Inhibits proliferation in breast, colon, and prostate cancer cells • Antioxidant and anti-inflammatory actions	Diffusion for respiratory or purifying purposes Topical in very low dilutions due to skin sensitivity
Linalool	Lavender, Coriander, Basil	• Induces apoptosis and cell cycle arrest • Reduces metastasis-related proteins • Antioxidant and neuroprotective • Supports immune modulation	Diffuse for calm and sleep Topical (1–3%) for relaxation, skin recovery, and tension relief
Terpinen-4-ol	Tea Tree (Melaleuca alternifolia)	• Induces apoptosis in melanoma and colon cancer cell lines • Inhibits tumor growth in animal models • Antioxidant and anti-inflammatory	Topical (1–2%) for skin and immune support Diffuse for purifying air Toxic if swallowed
α-Pinene / Incensole	Frankincense (Boswellia species)	• Promotes apoptosis and inhibits metastasis • Downregulates inflammatory cytokines • May inhibit angiogenesis • Incensole acetate shows neuroprotective and anti-anxiety effects (supportive during cancer care)	Diffuse for grounding and stress relief Topical (1–2%) in blends for skin and emotional balance

Notes for Integrative Understanding

• All these compounds target multiple pathways which means that they’re multimodal, meaning they can influence inflammation, oxidative stress, apoptosis, and tumor signaling simultaneously.
• Most evidence is preclinical (cell culture or animal studies), except for d-limonene and boswellic acids (related to frankincense resin) which have some early human data.
• Synergy matters: these compounds are often more effective in their natural combinations within whole essential oils, rather than as isolated chemicals. Also, combining a few of these essential oils brings a synergistic effect which means that together they are a hundred times more effective.
• Safety first: Always dilute topically, avoid ingestion unless under professional supervision, and consult your oncologist or an integrative medicine practitioner before use by presenting them with the evidence.

Safety first — very important

• Do not ingest essential oils unless a qualified clinician explicitly prescribes a pharmaceutical-grade, evidence-based protocol such as suggested by Dr. Zielinski.
• Patch test topicals (small area, 24 hours) before extended use. Many of the oils above (oregano, thyme, clove, citrus) can irritate skin or increase sun sensitivity (phototoxicity — especially citrus like bergamot).
• Pregnancy, breastfeeding, small children, and some medications (blood thinners, chemo agents) require special caution. Ask your oncologist or a qualified aromatherapist.
• Always consult our Responsible Usage Guide for internal use.

How to use these oils safely as supportive care

• Aromatherapy / diffusion is a low risk, widely used method: 30–60 minutes of diffusion in a well-ventilated room to reduce anxiety (lavender, frankincense), help sleep or uplift mood (citrus).
• Inhalation (steam or hands cupped) is another fast and popular method. Use 1–2 drops on a tissue or in a bowl of hot water for short, supervised inhalation sessions.
• Topical application is typically safe – dilutions for adults are 1–3% (that is ~6–18 drops essential oil per 30 ml carrier oil) depending on the oil; use lower concentrations for sensitive skin.
• Compresses are also an effective way to use essential oils. Use a cool or warm compress with 1–2 drops of your chosen essential oil in a carrier oil such as Castor oil (deeply penetrating).

Mainstream integrative experts

Dr. Eric Zielinski (Dr. Z) and Dr. Josh Axe have published and discussed essential oils and their supportive uses in cancer (books, podcasts and online articles). They promote evidence-informed, careful use of oils for symptom management and support, and often cite lab/ clinical literature while stressing safety and integration with conventional care. If you’re following integrative guidance, their resources can be a starting point — but always cross-check claims against primary studies and your oncology team.

A realistic, healthy-lifestyle

No single plant compound is a magic bullet. Evidence consistently shows that lifestyle matters hugely for cancer prevention and for supporting patients during and after treatment. Key elements of a healthy lifestyle include:

• a predominantly whole-food,
• plant-rich diet with
• adequate protein and
• healthy fats,
• regular physical activity suited to the person’s abilities,
• great sleep,
• tobacco & alcohol avoidance,
• a strict no sugar policy,
• stress management and
• maintaining a healthy body weight.

Complementary supportive tools such as aromatherapy can improve quality of life and fight the cancerous cells but they work best when combined with nutrition, movement and psychosocial support. Above all else, a mind focused the promise that is found in scripture – that His plan towards us is one of hope and a future. There is always Hope in Him and all the natural health He provided.