Trustworthy sources on aromatherapy, and how to judge the rest

Search for almost any essential oil and the first page of results mixes three kinds of writing: careful safety information, sincere enthusiasm, and selling. They can look much alike. A brand's blog may be beautifully designed and dotted with references, while a plain government page may be dull to read and far more useful. Here are the questions we ask before trusting a source, followed by the ones we keep coming back to.

Six questions to ask of any website or book

Who wrote it?

Look for a named author and a reason to trust them on this subject: training in aromatherapy, pharmacy, nursing, dermatology or research, and a willingness to say what they do not know. An anonymous page is not automatically wrong. It just gives you nothing to check.

Are they selling oils?

Many of the most visible aromatherapy pages belong to oil brands, or to independent distributors who earn commission on what they sell. Some are excellent. Still, anyone who profits from each bottle has a reason to suggest more drops, more oils and more uses. Look for affiliate links, discount codes and buy buttons. Phrases such as "therapeutic grade" and "clinical grade" are marketing language; no official body defines them.

Do they cite research, and what kind?

A good source ties its claims to studies and says what sort they were. A lab test showing that an oil kills bacteria in a dish tells you little about rubbing it on a person. Animal studies come next. Small trials in people are better, and reviews that pool many trials are better again. Be wary of one small study quoted as if it settled the question.

Do they talk about safety, with numbers?

Trustworthy writing gives dilutions as percentages and drops, mentions patch testing, and flags the people who need extra care: pregnancy, babies and children, pets, epilepsy, asthma. If a page recommends putting oils on neat as a matter of routine, or adding drops to a glass of water to drink, close the tab.

Do they claim to cure anything?

Essential oils do not cure cancer, infections, depression or diabetes. A source that suggests they do, or hints that you could use them instead of medicine you have been prescribed, has told you all you need to know about it.

When was it last checked?

Advice has moved on. Older books often suggested dabbing neat lavender on a burn, for instance, where current first aid from bodies such as the NHS is simply cool running water. A visible update date and signs of revision are good signs.

Sources we rely on

Public health bodies

The US National Center for Complementary and Integrative Health (NCCIH) has a plain-language page on aromatherapy and essential oils that summarises the research and its limits. It is a good first stop when a claim sounds too good. The NHS website covers complementary and alternative medicine in general, including how these therapies are regulated in the UK and what to ask a practitioner. The US National Cancer Institute's PDQ summary on aromatherapy and essential oils was written with cancer care in mind, but it is one of the most thorough free overviews of the studies. In Japan, the health ministry supports an information site on integrative medicine called eJIM, with pages for the public on a range of complementary therapies.

Systematic reviews

Cochrane reviews gather every trial they can find on one question and grade how reliable the evidence is. Reviews touching on aromatherapy, such as those on agitation in dementia and nausea after surgery, have generally found the evidence weak or low in quality. That is not a reason to give up on scent. It is a reason to be suspicious of anyone who sounds certain. For a quick sense of what research exists on a particular oil, search the free PubMed index for the oil's name plus "systematic review".

Safety references

Essential Oil Safety by Robert Tisserand and Rodney Young (second edition, 2014) is the reference most careful writers reach for on dilution limits, oil chemistry, interactions with medicines and which oils need special care. It is technical and costly, but libraries can often order it. For accidental swallowing, national poison services, such as the Japan Poison Information Center, give advice that is more reliable than any aromatherapy forum. And the International Fragrance Association's published standards show how industry limits materials such as phototoxic citrus oils in leave-on products, which helps when judging home recipes.

Professional bodies

The National Association for Holistic Aromatherapy (NAHA) in the US publishes safety information and educational standards. "Holistic" here means attending to the whole person, mind and body together, rather than one symptom. The International Federation of Aromatherapists (IFA) in the UK is a professional body with a code of conduct for members and safety guidance for the public. Also in the UK, the Complementary and Natural Healthcare Council keeps a voluntary register of practitioners, including aromatherapists.

These groups exist to support aromatherapy, so read them for safety and standards rather than as neutral judges of whether it works. The same goes for the many private associations in Japan that publish guides and run certificate exams: often helpful on safety basics, but not disinterested.

Using these sources alongside our guides

We try to hold our own pages to the same six questions, and how we write about essential oils sets out the rules. For a worked example of reading the research on one oil, see what the research does and does not show about lavender.

We link to the sources above freely and receive nothing from any of them. You are equally welcome to link to any page in this corner without asking first. If you spot something here that one of these sources contradicts, please let us know through the contact page.

No book or website, ours included, knows your health. If you are pregnant, caring for a baby, living with epilepsy or asthma, or taking regular medicines, ask a doctor or pharmacist before using essential oils. And if an oil causes a spreading rash or breathing trouble, or someone swallows it, get medical help straight away rather than reading up on it.