Peppermint essential oil to accelerate hair growth?

The skin naturally has hair follicles. The head contains approximately 1 million hair follicles, capable of producing up to 150,000 hairs depending on the individual. Originating from a hair follicle, the life of a hair alternates through different phases:

• The anagen phase (2 - 6 years): This is the hair growth phase during which there is proliferation of matrix cells that form the inner sheath of the root, the cortex, and the medulla of the hair shaft. The synthesis and pigmentation of the hair shaft only occur during this phase. Its duration determines the length of the hair, generally 1 cm per month.

• The catagen phase (2 - 3 weeks): The first sign of the catagen phase is the cessation of melanin production, the pigment responsible for the colour of our hair, in the hair bulb. The hair stops growing but remains attached to its hair follicle.

• The telogen phase (2 - 3 months): After the catagen phase, the follicles rest in a dormant phase, the telogen phase. The hair shaft eventually detaches from its follicle, which is already starting to produce a new hair beneath the skin.

Thus, within a head of hair, not all hairs are necessarily in the same phase as they each have their own life cycle. Some may be in a growth phase, while others are on the verge of falling out. This is why we lose approximately 50 to 100 hairs per day. This hair loss is normal and does not impact the appearance and density of the hair. The number of hair renewal cycles during an individual's lifetime ranges between 12 and 30. However, their life cycles are influenced by hormonal or nutritional variations. Peppermint essential oil is believed to stimulate hair growth. But is this really the case?

Thepeppermint essential oil is a natural oil extracted from the variety of mint known as mentha x piperita. It is obtained from the leaves of the plant through steam distillation, allowing for the production of a pure oil highly concentrated in active compounds. Already used in antiquity for its medicinal virtues and pleasant fragrance, this oil emits a fresh and herbaceous scent reminiscent of mint. It is often said that its use could stimulate hair growth, which has been the subject of studies on this matter.

A study has shown that the topical application of peppermint essential oil for 4 weeks at a concentration of 3% resulted in the induction of thick and long hair. Furthermore, an elongation of hair follicles from the epidermis to the subcutis was observed. The increase in the length of the hair follicle is associated with an increase in the length of the keratinised hair shaft. When these follicles elongate, it means that the hair grows longer, which is generally considered a sign of healthy hair growth.

Rosemary essential oil stimulates both the activity of the dermal papilla and alkaline phosphatase, which promotes blood circulation by relaxing vascular smooth muscles as well as the transition to the anagen phase. The dermal papilla, in turn, nourishes the hair follicles, ensuring healthy hair growth. The study also mentioned that peppermint essential oil remarkably increased the mRNA expression of the IGF-1 gene. This is a mitogen that promotes cell growth and survival, and contributes to hair thickening.

Thus, peppermint essential oil at a concentration of 3% has been found to promote the preservation of the vascularisation of the hair dermal papilla, which can contribute to the induction of the early anagen phase and therefore to hair growth.

How to use peppermint essential oil?

The essential oil of mint has a relatively high concentration. Using it in its pure form can cause irritations and allergic reactions. To avoid this, it is recommended to dilute it in a so-called "carrier" vegetable oil such as jojoba oil, sweet almond oil, coconut oil or olive oil.

ALANKAR S. A Review on peppermint oil. Asian Journal of Pharmaceutical and Clinical Research (2009).

OH J. Y. & al. Peppermint Oil Promotes Hair Growth without Toxic Signs. Toxicological Research (2014).

ABELAN U. S. & al. Potential use of essential oils in cosmetic and dermatological hair products: A review. Journal of Cosmetic Dermatology (2020).