Tea Tree Essential Oil - A Deep Dive

tea tree field

This is a deep dive into tea tree essential oil which has been found an effective topical antimicrobial agent that is active against a wide range of organisms. As we use this in our conditioning natural hand sanitisers we wanted to explain why.

Tea tree oil has clinical potential in hospitals and the wider community for the clearance of methicillin-resistant Staphylococcus aureus (MRSA). According to the “Time–kill studies of tea tree oils on clinical isolates” published in the Journal of Antimicrobial Chemotherapy that determined the kill rate of tea tree oil against several multidrug-resistant organisms, including MRSA, glycopeptide-resistant enterococci, aminoglycoside-resistant klebsiellae, Pseudomonas aeruginosa and Stenotrophomonas maltophilia, and also against sensitive microorganisms. 

They tested two types of tea tree oil. Standard oil had a 34.8% terpinen-4-ol and 5.5% cineole content, whereas a new second oil had a 43.1% terpinen-4-ol and a 1% cineole content.

The results confirmed that the second oil had increased antimicrobial activity when compared with the standard oil. But a rapid killing time (less than 60 min) was achieved with both tea tree oils with most isolates, however MRSA was killed more slowly than other organisms.

Measurements of time of killing by the two oils were made for each isolate and the activity of the standard oil was compared with that of the second oil. Repeat experiments gave similar results for all isolates and the growth controls showed at least a 103 increase in bacterial numbers by 6 h. The second oil “Clone 88” showed greater or the same activity against all isolates when compared to standard oil.

The two tea tree oils were more active against methicillin-sensitive S. aureus (MSSA) than against MRSA. Both isolates of MSSA were killed within 30 min by both oils. The standard oil killed the MRSA by 6 h. The second oil killed one of the two isolates of MRSA by 1.5 h but the other isolate was not killed until 3.5 h.

Tea tree is also used for infections such as acne, fungal infections of the nail (onychomycosis), lice, scabies, athlete's foot (tinea pedis), and ringworm and is why we made it one of the main ingredients in our alcohol free natural hand sanitisers.

The full research report