Encyclopedia · botanical
Peppermint oil
In a 2014 mouse study 3% peppermint oil grew more hair than 3% minoxidil, but no human trial of peppermint oil for hair has been found.
What it is
Peppermint oil is the steam-distilled oil of Mentha piperita, rich in menthol. It is sold diluted in scalp oils, often blended with rosemary.
How it works
In mice, peppermint oil raised skin thickness, follicle number and depth, and IGF-1 expression, with no change in body weight (Oh 2014). Menthol also causes a cooling, tingling sensation that users may read as the product "working".
What the studies show
- In C57BL/6 mice over 4 weeks, 3% peppermint oil in jojoba oil showed the most prominent growth compared with saline, jojoba oil and 3% minoxidil. Oh 2014
- Mouse regrowth after shaving uses young animals and does not translate directly to male pattern loss. No human trial of peppermint oil alone was found.
How it's used in studies
3% peppermint oil in jojoba oil, applied daily for 4 weeks in mice.
Side effects and safety
Essential oils can cause allergic contact dermatitis, and peppermint oil hypersensitivity is documented in case reports (Dooms-Goossens 1977). Dilute it and patch-test.
Bottom line
Weak evidence. It is cheap and pleasant to use, but the data are from mice only. Never replace minoxidil with it.
Fun facts
A mouse study found peppermint oil outperformed 3% minoxidil head to head, which is much of why it went viral (Oh 2014).
Studies 2
Oh JY et al. Peppermint oil promotes hair growth without toxic signs. Toxicol Res. 2014
Tested: 3% peppermint oil vs saline, jojoba oil and 3% minoxidil
Result: The peppermint group showed the most prominent growth, with higher dermal thickness, follicle number and IGF-1 expression.
Read the study ↗Dooms-Goossens A et al. Turpentine-induced hypersensitivity to peppermint oil. Contact Dermatitis. 1977
Tested: peppermint oil exposure
Result: Documents allergic hypersensitivity to peppermint oil.
Read the study ↗Related
- Rosemary oilRosemary oil became the internet's "natural minoxidil" from one small 2015 trial that had no placebo group and has never been replicated.
- Lavender oilLavender oil thickened skin and increased follicle numbers in mice in 2016; there is no human hair trial, and a debated hormone-disruption concern exists in young children.
- Castor oilCastor oil is a thick sealant that suits dry hair, but no controlled human trial shows it grows hair, and in rare cases it has matted a whole head of hair irreversibly.