Manuka oil

What is manuka oil?

Manuka oil is an essential oil distilled from the leaves and branches of Leptospermum scoparium, a shrub native to New Zealand and southeastern Australia. Manuka is one of three Myrtaceae plants commonly called “tea tree,” along with Australian tea tree (Melaleuca alternifolia) and kanuka (Kunzea ericoides) (Lis-Balchin et al., 2000). The same plant is the source of manuka honey, but the oil is a different product with a different chemistry.

What the research says

Evidence for manuka oil comes from laboratory studies. A study comparing the three “tea tree” oils found that manuka had stronger antifungal activity than kanuka but was not as potent as Australian tea tree oil. It also found that manuka samples varied considerably in their antimicrobial activity, and that, unlike Australian tea tree oil, manuka and kanuka oils had not been tested for toxicity, which the authors said called for caution (Lis-Balchin et al., 2000).

A later lab study of six essential oils found that manuka oil was among those active against several Candida yeast species (Elisa et al., 2021). We found no human clinical trials of manuka oil for skin or nail fungus. Marketing claims that manuka oil is “more powerful than tea tree oil” against nail fungus are not supported by the comparative lab data we found. Lab tests also say little about how an oil behaves once it is diluted in a carrier, exposed to air and applied to a thick, hard nail. Until human studies are done, manuka oil should be treated as an unproven ingredient for nail problems.

How it’s used in products

Manuka oil is used in skin care, aromatherapy and natural antiseptic products, and in some nail oils as one of several essential oils. Concentrations are rarely disclosed, and the oil’s composition can vary by where and how the plant was grown.

Because manuka oil has not been well studied for safety, use it cautiously. Dilute it before applying to skin, keep it away from the eyes and do not swallow it. Stop using it if redness, itching or a rash appears, and test a small area first if you are sensitive to tea tree or other essential oils. The 2000 comparative study found that all three “tea tree” oils reduced uterine contractions in animal tissue, and the authors advised caution around childbirth (Lis-Balchin et al., 2000); if you are pregnant, talk to your doctor before using it. For nail problems, have a clinician confirm the cause, especially if you have diabetes or poor circulation.