Frankincense contains compounds that kill cancer cells in laboratory studies, and one small human trial in breast cancer showed promising early results. But there’s a critical distinction most sources gloss over: the steam-distilled essential oil you’d buy in a store is chemically different from the resin extracts used in research, and it likely doesn’t contain therapeutic levels of the compounds doing the heavy lifting. Understanding this difference is essential before deciding how to use frankincense in any form.
What Actually Fights Cancer in Frankincense
The anticancer activity in frankincense comes primarily from a group of compounds called boswellic acids, particularly one known as AKBA. These are heavy, large molecules classified as triterpenes. In lab studies, boswellic acids trigger cancer cell death through several pathways: they interfere with enzymes cancer cells need to replicate, cut off blood supply to tumors, and activate the self-destruct sequence (apoptosis) that cancer cells normally disable. They’ve shown activity against prostate, colon, melanoma, liver, leukemia, brain, and bladder cancer cell lines.
One especially notable finding: when researchers tested frankincense essential oil from Boswellia sacra on several types of human breast cancer cells alongside normal breast cells, the oil triggered cancer cell death while normal breast tissue was highly resistant to its effects. This selectivity is unusual and part of what makes the research interesting.
The Essential Oil vs. Extract Problem
Here’s the part that matters most for anyone trying to use frankincense oil at home. Steam-distilled frankincense essential oil, the kind sold in small bottles at health stores, is composed mainly of lighter volatile compounds called monoterpenes and sesquiterpenes. When researchers analyzed the chemical makeup of steam-distilled frankincense oil using gas chromatography, they identified over 90 compounds but detected no diterpenes in any sample. Boswellic acids are triterpenes, even heavier than diterpenes, meaning they are too large and heavy to evaporate during the steam distillation process.
The studies showing anticancer activity use either the whole oleo-gum resin, solvent-based resin extracts, or isolated boswellic acid compounds. These are not the same product as essential oil. Some essential oil research does show activity against cancer cells, likely from other compounds in the oil, but the most robust and well-studied anticancer mechanisms involve boswellic acids that standard essential oils contain in negligible amounts, if at all.
If you’re looking for boswellic acid content specifically, standardized Boswellia serrata resin extracts sold as supplements are a closer match to what researchers actually use. These are typically capsules or tablets with a known percentage of boswellic acids listed on the label.
What Human Studies Actually Show
Nearly all frankincense cancer research has been done in petri dishes or animals. The most significant human data comes from a small trial at MUSC Hollings Cancer Center, where 20 breast cancer patients took a Boswellia extract daily during the days between diagnosis and scheduled surgery. Researchers compared tumor growth rates before and after treatment and found a statistically significant reduction in tumor proliferation compared to women who didn’t take the extract. Side effects were minimal.
The lead researcher, surgical oncologist Nancy Klauber-DeMore, was direct about the limitations: the study was designed only to detect whether any anticancer effect existed in humans, not to measure survival or recurrence. She emphasized that patients should not replace standard breast cancer treatment with Boswellia. Larger trials would be needed before it could be considered part of a treatment plan.
In animal studies, AKBA at modest doses suppressed tumor growth in prostate cancer models. And boswellic acids have been studied more extensively for brain swelling around tumors, where the European Medicines Agency approved boswellic acid as an orphan drug for treating brain edema.
Absorption Is a Major Barrier
Even when you take a standardized boswellic acid extract by mouth, your body struggles to absorb it. AKBA has poor oral bioavailability, which is a well-documented limitation for clinical use. Researchers are working on advanced delivery systems like nanoemulsions to improve absorption. In one study, a nanoemulsion formulation nearly quadrupled peak blood levels of AKBA compared to the standard form. But these formulations aren’t commercially available yet.
Taking boswellic acid supplements with fatty foods may help somewhat, since these compounds are fat-soluble. Some supplement manufacturers use lipid-based formulations or pair boswellic acids with other ingredients to improve uptake, though the evidence for most of these approaches is limited.
Forms and How People Use Them
People use frankincense in three main ways in the context of cancer, each with different evidence behind it.
- Standardized Boswellia resin extract (oral capsules): This is closest to what researchers use in studies. Products typically list the percentage of boswellic acids, often 30% to 65%. This form delivers measurable amounts of the active compounds to your bloodstream, though absorption remains limited.
- Steam-distilled essential oil (topical): Applied to skin after diluting with a carrier oil. People commonly use a ratio of about 1:1 with coconut, almond, or similar oil, as undiluted application can cause burning. No human cancer trials have tested topical essential oil application, and the skin is an effective barrier against absorbing most compounds into deeper tissue or the bloodstream.
- Steam-distilled essential oil (inhaled or diffused): Used primarily for relaxation, stress relief, or nausea management during cancer treatment. This is a supportive wellness practice, not an anticancer intervention.
Safety and Drug Interactions
Frankincense resin is on the FDA’s Generally Recognized As Safe (GRAS) list, which allows its use as a food additive. Multiple clinical trials have found no long-term irreversible adverse effects. The most common side effects from oral use are nausea and digestive upset.
Drug interactions are a real concern, though. The MUSC clinical trial specifically excluded patients taking medications known to interact with boswellic acid. Boswellic acids can affect how your liver processes certain drugs, potentially changing blood levels of chemotherapy agents or other medications. If you’re undergoing cancer treatment, the compounds in Boswellia could theoretically either reduce the effectiveness of your medications or amplify their toxicity.
For topical essential oil use, the primary risk is skin irritation. Diluting with a carrier oil and testing on a small patch of skin first is standard practice. Frankincense essential oil is considered non-toxic, and allergic reactions are uncommon but possible.
What This Means in Practical Terms
The research on frankincense and cancer is genuinely interesting but firmly in the early stages. Lab studies show clear anticancer mechanisms. One small human trial demonstrated a real biological effect in breast cancer patients. But no study has shown that frankincense in any form improves cancer survival, prevents recurrence, or can replace surgery, chemotherapy, or radiation.
If you want to use frankincense alongside conventional treatment, a standardized Boswellia resin extract gives you the best chance of actually getting boswellic acids into your system. Steam-distilled essential oil lacks the key compounds in meaningful quantities, regardless of what many wellness websites claim. And because boswellic acids can interact with other drugs, anyone on cancer treatment should have that conversation with their oncologist before adding it. The U.S. FDA recognizes boswellic acid as a dietary supplement, not an approved cancer treatment, so no product can legally claim to treat or cure cancer.