How to Use Tea Tree Oil for Hair Health, Straight from an Expert

Like many other essential oils, tea tree has been used for medicinal purposes in the Eastern world for hundreds of years. Also known as melaleuca oil, it was originally used by the aboriginal people of Australia who derived it from the leaves of the (quite pretty) flowering Australian tea tree via steaming, according to the Mayo Clinic. But you probably know it as that intriguing, trendy ingredient popping up in all of your favorite hair care products.

While the Mayo Clinic points out that tea tree oil may be effective at treating acne, relieving symptoms of athlete’s foot and getting rid of lice (yikes), we’re here for its more general, everyday hair care benefits.

“Its main property is that [tea tree oil] effectively helps to fight bacteria and fungus,” says Dr. Jenelle Kim, an expert in Chinese medicine and the founder and formulator of JBK Wellness Labs in San Diego. “It is a strong, natural ingredient that is great for sensitive skin and scalp. The scalp is very sensitive and is vulnerable to skin imbalances, itchiness and dandruff—which are usually caused by minor fungal infections.”

Dr. Kim says that tea tree oil is most beneficial when used in shampoos since this step in our hair care routine is the “cleansing phase” where we “focus on massaging the scalp,” but adds that it can also be used as a leave-in conditioning treatment.

When using a shampoo that contained only 5 percent tea tree oil, volunteers in a study published in the Journal of the American Academy of Dermatology who used it for at least four weeks said that it significantly reduced their dandruff—giving us visions of busting out our favorite black sweaters this winter. It can also help clean your hair and keep it strong and healthy, as Dr. Kim explains.

“Dandruff usually clogs your hair follicles, which directly affects the growth and health of your scalp,” she says. “When using tea tree oil, it will facilitate hair growth and also help to moisturize the scalp while preventing excess oil buildup. It will rebalance the scalp and assist in overall hair health.”

“Usually you can see the difference quickly,” she says. “After one or two washes, you will see a noticeable difference. If you have dandruff, a dry scalp or psoriasis, you should use tea tree oil daily.”

This all sounds like music to our ears and even borderline magic for our dry winter scalp (so long, flakes!). But there are, inevitably, some possible side effects to watch out for when using tea tree oil. It’s important to note that the following is considered the exception, not the rule since tea tree oil is considered to be a generally safe essential oil when used topically.

The Mayo Clinic says to keep an eye out for any skin irritation or rashes, itching, burning, stinging, scaling, redness or dryness, and advises that those with eczema refrain from use altogether. Keep in mind that tea tree oil is not meant to be ingested and is toxic when swallowed, so please make sure it’s always out of your children’s reach. If anyone in your household does swallow some, get them medical attention immediately, especially if they start acting confused or lose muscle control, coordination or consciousness.

To help avoid these adverse effects—which will likely only occur if you have a (highly unlikely) allergic reaction to tea tree oil—Dr. Kim says to check the labels on the products you’re considering to see if “all-natural” tea tree oil is “one of the main active ingredients,” and if it’s complemented by others like “nettle, sea buckthorn and hibiscus.”

“You want to make sure that the product is free of parabens and harsh chemicals,” Dr. Kim says. “Avoid toxic preservatives, sulfates and artificial fragrances since, in the long run, they will further create an imbalance in the health of your skin and scalp. If for any reason a person experiences an allergic reaction, they should discontinue use and consult with a physician.”

If you’re still wary about using a product that might not be up to your all-natural standards, Dr. Kim is pro-DIY but says that we should always reach for fresh tea tree oil when mixing it into our favorite shampoos ourselves. Add 5 to 10 drops of tea tree oil into your shampoo bottle, shake it to mix together before applying it to your hair. 

“Fresh tea tree oil should always be used, especially on the scalp and skin,” she says. “[Because] when tea tree oil oxidizes, there’s a greater chance of skin reactions. Fresh tea tree oil will smell green and clean. When it has oxidized, it will have a harsh smell and should not be used.”

When in doubt, grab a tester and dab a little bit on the inside of your forearm. No reaction? Great. Get your healthy hair on.