The use of peppermint oil for hair growth is not new at all to the natural hair community. Search the archives of hair care forums and blogs, and you will find at least one thread or article devoted to it. Nonetheless, there has not been a concrete study on peppermint oil for hair growth … until now.

1. Let’s talk about previous research of peppermint oil
Over the years, the benefits of peppermint oil have been evidenced in other regards.

“… peppermint has been reported to show anti-inflammatory, antimicrobial, and antifungal activities as well as strong antioxidant activity, and antiallergenic and antitumor actions. Several clinical trials examining the effects of peppermint oil (PEO) on irritable bowel syndrome have been reported. However, experimental trial of PEO in its hair growth activity has not been fully reported.”

In December 2014, a thorough study on the growth benefits of peppermint oil was finally published.

2. The study: methodology and experiment

“The aim of this study was to address the therapeutic potential of peppermint oil (PEO) for hair loss via the comparative analysis between PEO and minoxidil.”

Some of us are already familiar with minoxidil for hair growth, whether first-hand or through hearing the experiences of others. Research also supports this use and doctors widely recommend topical minoxidil (Rogaine®) to treat some forms of alopecia.

This particular study was aimed at analyzing the effectiveness of peppermint oil versus the widely used and researched treatment for hair loss, minoxidil. For the experiment, 100% pure peppermint essential oil was diluted in jojoba oil (a carrier oil). The mixture was then applied topically once a day, six days a week, for approximately a month.

The experimental design was as follows:

“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.”

3. The findings
The results of the study showed that peppermint oil had the most pronounced effect on hair growth compared to the other three compounds. Additionally, the oil showed significant increases in follicle count, or hair density. Here is a snapshot of the results:

- “At week 4, PEO showed hair growth at about 92%, whereas MXD about 55%”- “The depth, size, and number of hair follicles were also markedly increased in PEO treated skin.”- "PEO showed remarkably increased IGF-1 mRNA expression at week 2, whereas MXD at week 4.” (NOTE: IGF-1 supports cell growth and survival while also playing a role to increase hair thickness).

4. So what does this mean?
For those of you who use peppermint oil for hair regrowth, you might actually be onto something!

“In conclusion, our experimental data suggest that 3% PEO facilitates hair growth by promoting the conservation of vascularization of hair dermal papilla, which may contribute to the induction of early anagen stage. In addition, PEO effectively stimulated hair growth in an animal model via several mechanisms and thus could be used as a therapeutic or preventive alternative medicine for hair loss in humans.”

SOURCE:
Ji Young Oh, Min Ah Park, and Young Chul Kim. "Peppermint Oil Promotes Hair Growth without Toxic Signs". Toxicology Research, Volume 30, Issue 4 Dec. 2014, pp. 297–304.