Tea tree oil is an oil that comes from comes from one species of Melaleuca alternifolia tree. It's made by steam distilling the leaves of this native Australian tree. There are hundreds of types of Malelaleuca alternifolia tree but only one produces tea tree oil. The clear oil produced from the Melaleuca alternifolia tree has the scent of camphor and has been used as an antiseptic in Australia and for other medicinal purposes for decades. Studies show that tea tree oil has activity against bacteria, fungi and viruses, including the herpes simplex virus that causes cold sores and genital warts.
Because tea tree oil has anti-bacterial properties, it may be beneficial for treating acne, the most common skin problem among adolescents, teens and young adults. Acne is a skin disease characterized by overproduction of sebum and abnormal shedding of skin cells inside hair follicles. The excess sebum and dead skin cells block the opening of the hair follicle called the pore. Bacteria then feed on the dead skin cells, leading to inflammation. Tea tree oil appears to kill the bacteria that cause these inflamed acne lesions. This leads to a reduction in their number.
How well does it work? One study compared the effects of 5% topical tea tree oil with 5% benzoyl peroxide for the treatment of acne. Both benzoyl peroxide and tea tree oil reduced the number of inflamed acne lesions, although benzoyl peroxide was faster. On the other hand, tea tree oil users experienced less skin irritation than those that used benzoyl peroxide. The benefit of tea tree oil for treating acne was confirmed by a second study carried out in Iran. It may be more beneficial as an acne treatment when combined with a beta-hydroxy acid such as salicylic acid to promote shedding of dead skin cells that clog and congest pores.
Tea tree oil may also be effective for treating other skin conditions including head lice, scabies and some forms of dandruff. It helps to block the transmission and spread of methicillin-resistant Staph, a hardy form of bacteria that resists treatment with most antibiotics. Methicillin-resistant Staph, also known as MRSA, can cause serious skin infections or even death when it enters the bloodstream.
Tea tree oil also has anti-inflammatory properties that make it effective for treating itching and skin inflammation. Because of its anti-bacterial, anti-viral and anti-fungal properties, it's sought after by makers of cosmetic and personal care products as an antiseptic and as an ingredient for treating acne. That's why you can find it in some acne treatment products, facial cleansers, toners, astringents, facial moisturizers, shampoos and hair conditioners.
Is it safe? Tea tree oil appears to be safe as long as it isn't taken by mouth. Used orally, tea tree oil can be toxic causing depression of the central nervous system and blood abnormalities. It can also cause skin irritation, especially at higher concentrations. A small number of people experience allergic reactions to tea tree oil and can develop an allergic contact dermatitis after using it. It's also toxic to some animals, especially dogs and cats and shouldn't be applied to the skin of a pet or used around animals. Even small quantities have been known to be fatal to pets. It doesn't seem to have the same impact on fish since dilute tea tree oil formulations are used to treat bacterial and fungal infections in aquarium fish. Humans are unlikely to experience any serious side effects from tea tree oil as long as they avoid taking it by mouth.
All in all, tea tree oil is an ingredient that's growing in popularity because of its ability to fight bacteria, viruses and fungi that cause skin problems like acne, head lice and dandruff. It can be used as an alternative to benzoyl peroxide for treating acne. It may cause skin irritation and allergic reactions in some people, and people with eczema or sensitive skin should use tea tree oil with caution.