Peppermint oil - for itchy scalps, fungus and bacteria!
Jam_Noire asks,' I know people who use peppermint oil in their hair to reduce itchy/dry scalp. Can you discuss this?'
Peppermint oil is known to contain menthol (the pretty crystals to the right) which is responsible for many of its active effects. Here is the research I found:
1. Anti itching effect
Menthol is recognised by the FDA as an anti-itching agent (itching in medicine is known as pruritus). The concentration required is around 1.5% (Fed Regist, 72(43):9849-52, 2007). It is not approved or effective as a dandruff medication however.It is effective in alleviating itchiness.
2. Cooling effect
The tingling and cooling effect associated with peppermint oil happens because menthol stimulates the same nerves that react to cold (these nerves are actually identified by scientists as menthol receptors). (Nature, pp 204-208, 2007 and Cell, pp. 705–715, 2002). It is called a cooling sensation because while the area feels cool, it is actually not being cooled at all.
3. Aromatherapy and brain effect
There are quite a few books describing aromatherapy related effects of peppermint oil and menthol. I have not quoted any because I did not see scientific research in these texts.
I did however find that using shampoo with menthol has been shown to increase some aspects brain activity (The double effect of l-menthol on the brain activity, Yoshida et al, CABI abstracts). Interesting non?
4. Antibacterial and Antifungal effect
Menthol has antibacterial and antifungal properties. In this particular article, the authors reviewed and quoted several papers which indicated that indeed menthol can kill several types of bacteria and fungi (Journal of the American Academy of Dermatology, pp 873-878,2007)
Are you a fan of peppermint oil? If so, how do you use it?