The study was performed on mice, so the results may not directly correlate to results on humans. However, I still believe this study to be highly beneficial.
According to the study, "This study investigated the effect of peppermint oil on hair growth in C57BL/6 mice. The animals were randomized into 4 groups based on different topical applications: saline (SA), jojoba oil (JO), 3% minoxidil (MXD), and 3% peppermint oil (PEO). The hair growth effects of the 4-week topical applications were evaluated in terms of hair growth, histological analysis, enzymatic activity of alkaline phosphatase (ALP), and gene expression of insulin-like growth factor-1 (IGF-1), known bio-markers for the enhanced hair growth. Of the 4 experimental groups, PEO group showed the most prominent hair growth effects; a significant increase in dermal thickness, follicle number, and follicle depth."
The mice group that I concentrated on while reading was the peppermint oil group. The mice were shaved and then the compound was applied to the shaved area once a day, six days a week, for 4 weeks. The group that used peppermint had a more significant increase in hair growth than the other groups. By the 4th week, this group had 92% hair growth while the Minoxidil, a product used to fight hair loss, group experienced approximately 55% hair growth. By week two, the peppermint oil group had 95% and 66% more increased dermal thickness than the other groups. Additionally, by the 4th week, it had 120% and 81% more dermal thickness. The rapid increase of hair growth and the increase of thickness started from week two. In addition to proving that peppermint oil caused rapid hair growth and increase in hair thickness, the study also revealed that "the number of hair follicles increased as the hair regrew." At week four, the mice group using peppermint oil had 740% and 307% more hair follicles than the other two groups.
|Taken from here|
In order to understand this study, you need to understand the phases of hair growth. These mice's hair growth was in the telogen stage and the peppermint oil induced a rapid anagen hair growth. The oil actually forced the hair to grow while it was supposed to be at its resting stage!
More on these two phases according to Avanti Electrolysis's article:
During the telogen, or resting, phase the hair and follicle remain dormant anywhere from 1–4 months. Ten to fifteen percent of the hairs on one's head are in this phase of growth in any given time. The anagen phase begins again once the telogen phase is complete. The preceding hair strand is pushed up and out by the new, growing strand. The process causes the normal hair loss known as shedding.
The anagen phase is known as the growth phase. It begins in the papilla and can last up to eight years. The span at which the hair remains in this stage of growth is determined by genetics. The longer the hair stays in the anagen phase, the faster and longer it will grow. During this phase, the cells in the papilla divide to produce new hair fibers, and the follicle buries itself into the dermal layer of the skin to nourish the strand. About 85% of the hairs on one's head are in the anagen phase at any given time."
Screenshots taken from the study are below. Please read more on the actual study's website here.
I've been applying a homemade scalp oil as often as possible. This is wash day (after I wash and style my hair. I style in 8 braids for a braidout, apply the mix to my scalp, and massage for a minimum of five minutes), prepoo day (I section my hair in four and apply coconut oil to my hair. While my hair is sectioned, I apply the mix to my scalp and massage for a minimum of five minutes), and 1-2 days in between.
My oil mix consists of Mielle Organics Mint Almond Oil, olive oil, castor oil, peppermint oil, and jojoba oil. These oils are great for the scalp and jojoba oil mimic our scalp's natural sebum.
I recommend just using MO Mint Almond Oil because it already has peppermint oil in it. Pour it in an applicator bottle (the basis for my scalp oil mix is this oil. I poured it into the applicator oil above and then put in a few drops of the other oils and shook to mix) and apply it to your scalp a few times per week.
See you Wednesday for #TheWashDayExperience!
Oh, Ji Young, Min Ah Park, and Young Chul Kim. “Peppermint Oil Promotes Hair Growth without Toxic Signs.” Toxicological Research 30.4 (2014): 297–304. PMC. Web. 28 June 2016.