Peppermint Oil for Hair Loss – Study Review

Peppermint oil surrounded by peppermint leaves

There are many causes of hair loss and, as such, many viable treatment options.

Some options have better results than others, and some even have less side effects than the more conventional treatments – including Propecia and Rogaine.

One such possible option for treatment? Peppermint Essential Oil (PEO).

This article will discuss the leading cause of hair loss – Androgenetic Alopecia (AGA), and how peppermint oil may be useful in treating and, perhaps even reversing, its effects.

It will also introduce the scientific proof behind these claims and provide a look at some more conventional treatment options.

What Is Peppermint Oil?

A cross between spearmint and watermint, peppermint is a hybrid plant within the Lamiaceae family (1). It’s used often in food (in flavoring tea, gum, mints, and ice cream), but it has also begun to find its place in the cosmetics and health industry.

Can It Treat Hair Loss?

To understand the ways that peppermint oil may be useful in treating thinning and balding, it’s important to know why hair loss occurs.

While there are many causes of balding – from illness and injury to hormonal changes to stress – the main cause is Androgenetic Alopecia (AGA) (2). This occurs in both men and women, and it’s also known as pattern hair loss.

But what’s the cause?

The exact cause has yet to be pinpointed by scientists. Though, there are a few factors which are believed to play a role. These include:

  • Genetics
  • Lifestyle
  • Androgen (DHT) sensitivity

But the last one, in particular, is of interest to researchers.

Dihydrotestosterone (DHT) is an androgen hormone that’s a by-product of the interaction between testosterone (the male sex hormone) and 5-alpha-reductase (5AR), an enzyme (3).

It’s produced mainly in the testes, though free testosterone (fT) which travels throughout the body can also be converted to DHT.

Where does fT travel?

The hair follicle is one such place where fT dwells and is converted to DHT, which is of importance to hair loss sufferers.

In many people, this conversion causes no harm. However, men and women with AGA will experience a process called follicle miniaturization (2).

Of course, the process of hair loss isn’t quite so straightforward. There are many other factors which contribute to hair loss, including poor blood flow and lack of oxygen, both of which are side effects of miniaturization (4, 5).

So, what role can peppermint oil play?

As shown by research, quite a few. For example, it may be able to (6, 7, 8, 9):

  • Stimulate the anagen growth phase
  • Improve blood supply
  • Treat antifungal and antibacterial infections
  • Prevent and treat inflammation

When combined, these abilities make peppermint oil an intriguing option.

The Scientific Proof

Let’s look closely at a few studies which seem to support PEO’s use in treating hair fall. This will include a breakdown of the participants, methods, and results, as well as a look at possible study limitations.

Study: Peppermint oil promotes hair growth without toxic signs

The most promising study, which showed the direct results of PEO use on balding, was performed in 2014 on mice (6).

The mice – 20 in total – were shaved on the dorsal area and then split into four groups. The groups received different topical treatments, which were:

  1. Saline (SA)
  2. Jojoba Oil (JO)
  3. 3% minoxidil (MXD)
  4. 3% Peppermint Essential Oil (PEO)

The treatment was applied to the dorsal area six days per week for four weeks.

Hair growth was measured by two methods. The first were photographs, which were taken at regular intervals throughout the four-week study. They were each categorized as follows:

  • 0: no hair growth
  • 1: less than 20% growth
  • 2: 20% to less than 40% growth
  • 3: 40% to less than 60% growth
  • 4: 60% to less than 80% growth
  • 5: 80% to 100% growth.

The second method involved skin biopsies, which were taken at the end of the study.

The groups that received either saline or jojoba saw minimal hair growth throughout the study. On the other hand, both the minoxidil and the PEO groups saw significant hair growth from week two.

This growth continued for both groups, even at the end of the study, which indicates a prolonged anagen phase of hair growth.

But what about the biopsy results?

First, the biopsies show elongation of the hair follicles and shaft in the minoxidil and PEO groups.

Second, the PEO group had seven times and three times more hair follicles than the saline and jojoba groups, respectively.

And, researchers even found that blood circulation to the scalp was increased via monitoring of Alkaline Phosphatase (AP) activity.

In conclusion, researchers determined that:

“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.”

Study Limitations and Considerations

While the above results seem promising, there are a few things to consider.

Foremost, the study was carried out on mice.

Mice and rats are used often in scientific studies and while their hair growth cycle is quite similar to that of humans, it’s not the perfect model for comparison. This is especially true when you consider that the mice in this study were not suffering from alopecia, but they were instead shaved.

The study was also only four weeks long, which is a very short amount of time to consider peppermint oil to be the treatment for hair loss.

Study: Antibacterial and antifungal activity of ten essential oils in vitro

While the above study highlighted the direct effects of PEO on hair growth, there are other studies which indicate PEO’s many other beneficial properties.

One such study was performed in 1996, and it indicated PEO as an effective antibacterial and antifungal agent (8). The study compared the effects of 10 different essential oils against 22 bacterial and 12 fungal strains.

Peppermint oil performed well, inhibiting all 22 of the bacterial strains and 11 out of twelve of the fungal strains.

What do these results mean for hair loss sufferers?

AGA is the most common cause of thinning and balding in men (and one of the leading causes of hair fall in women). But it’s not the only cause.

Bacterial and fungal overgrowth, which can occur on the scalp, may also contribute to balding (10).

Infections, like tinea capitis and dandruff, can cause inflammation, itching, and general irritation. The act of scratching can dislodge hairs and the infections themselves can disrupt the hair growth cycle.

By treating infections on the scalp, you make it possible to improve the overall environment. This is beneficial for hair follicle health and may result in hair growth.

Study: Anti-Inflammatory properties of menthol and menthone in schistosoma mansoni infection

Bacterial and fungal infections aren’t the only conditions that can cause inflammation of the scalp.

Parasites can also contribute. And while parasites may not be a common cause of balding, this next study does shed some light on how peppermint oil may be helpful in reducing inflammation.

The study, performed in 2016, focused on two components of peppermint oil – menthol and methone (9).

The mice used in the study were split into five groups. They were:

  1. Negative control, which was not infected with the parasite
  2. Positive control, which was infected with the parasite, but not treated
  3. Mentha 15, which were treated for 15 consecutive days with 50mg/day
  4. Mentha 60, which were treated for 60 consecutive days with 50mg/day
  5. Praziquantel, a drug commonly used in the treatment of the infection

The only group not infected with the parasite was the negative control.

NOTE: The menthol in this study was derived from a pharmaceutical source – Mentaliv, which is commonly used to treat Irritable Bowel Syndrome (IBS). Its components include up to 55% menthol and up to 32% menthone.

To determine the effects of the parasitic infection and the efficacy of the treatments used, researchers monitored cytokine levels (11). These are pro-inflammatory proteins and, as such, will be present in larger numbers when infection is present.

After 61 days of infection, the cytokine levels were taken.

The Mentha 60 experimental group exhibited the best results when compared with the positive control. More specifically, IL-4 levels were reduced by 53.5%, and IL-10 levels were reduced by 62%.

These reductions were even better than those in the Praziquantel treatment group.

But does this mean that peppermint oil, of which menthol and menthone are major components, can also help to fight infection and accompanying symptoms (12)?

Study Limitations and Considerations

As mentioned, menthol and methone are both major components of peppermint oil. This means that their properties very likely contribute to the essential oil’s properties, but we can not be sure by how much.

The formulation used in this study contained up to 55 percent menthol and up to 32 percent menthone. This is almost 15 percent more menthol and almost 9 percent more menthone than is found in most formulations of peppermint oil.

The study was also carried out on mice and as another factor, the parasite, was introduced there is likely to be quite a difference of results between mice and humans and their reaction to – and treatment of – the parasite.

Study: Topical menthol increases cutaneous blood flow

Menthol, the same ingredient mentioned in the previous study, may provide another benefit to men and women with thinning and balding – it increases circulation to the scalp (7).

What exactly does this mean, and how is it helpful?

As follicle miniaturization sets in, the surrounding area becomes inflamed and irritated (2). This inflammation affects every part of the hair follicle, including the bulb.

The bulb is located at the base of the follicle. It’s connected to the scalp’s blood vessels which, in turn, makes it the source of all nutrients and oxygen within the hair follicle.

When miniaturization occurs, the connection between the bulb and the blood vessels is slowly strangled. It can eventually become cut off entirely, which will result in irreversible balding.

A diagram of the hair follicle

So, by increasing blood flow to the scalp the chances of nutrient and oxygen delivery are improved. This is critical if hair is to regrow and thrive in its environment.

In fact, oxygen plays a more important role in hair loss (and growth) than was once thought. Here’s how.

As mentioned above, DHT is produced from the interaction between testosterone and 5AR. This occurs in various parts of the body, but we’ll focus on the scalp and hair follicles specifically.

When this interaction occurs, more than just testosterone and 5AR are needed. Oxygen is also a critical component of the process (13).

However, the interaction doesn’t need much oxygen to be completed. So, even low-oxygen environments (such as the scalps of people with AGA) can still produce DHT.

By increasing oxygen levels to the scalp, you reduce the levels of DHT being produced. Here’s why.

There’s another by-product of testosterone and 5AR that’s often overlooked – estradiol (14, 15). And interestingly, its production also requires oxygen (13).

This means that a high-oxygen environment will produce both DHT and estradiol. And why is that good? Because this estrogen hormone has actually been shown to induce hair growth (16).

So, how can peppermint oil help?

In 2016, researchers from the United States showed that menthol increases cutaneous blood flow when applied topically (7). This was measured by Cutaneous Vascular Conductance (CVC), and the higher the concentration the more blood flow to the area.

As such, it would make sense that menthol-containing extracts (such as peppermint oil) would induce blood flow and improve the environment for hair. This is similar to one of minoxidil’s suggested mechanisms.

Side Effects and Contraindications of Peppermint Oil Supplementation

As with any ingredient, there are certain risk factors which must be considered before using.

Peppermint oil should be avoided by women who are pregnant or breastfeeding, as little evidence is available on its use in such populations (17).

Use on children isn’t recommended, and use near the eyes, mouth, or nose should be avoided.

While rare, adverse effects can occur when PEO is applied to the skin. These are typically minor, and they include (18):

  • Rash
  • Burning
  • Irritation
  • Redness
  • Flushing of the surrounding skin

If you’re allergic to peppermint oil’s components, including menthol and menthone, use should be avoided. The signs of an allergic reaction include (19, 20):

  • Itching
  • Hives
  • Redness
  • Coughing and/or wheezing
  • Difficulty breathing
  • Nausea/vomiting/diarrhea

If you suspect an allergic reaction, seek emergency medical attention. In severe cases, the reaction can progress and result in anaphylaxis which, if left untreated, is fatal.

How to Use Peppermint Oil

While the jury is still out on the true efficacy of peppermint oil for hair growth, you may still be interested in giving it a try.

There are many ways you can benefit from the supplementation of peppermint oil.

Dilute Your Essential Oils

First, a note: As an essential oil, PEO must be diluted before it’s applied to the skin. PEO should NOT be taken orally unless it’s designated for oral consumption, and it should be heavily diluted or taken in capsule form.

When using essential oils, it’s important to combine them with a carrier oil.

These help to deliver the essential oils more efficiently, and they also prevent burns/irritations that can be caused by undiluted essential oils.

As a general rule of thumb, the dilution rate should be 5mL of carrier oil for every drop of essential oil.

Apply to the Scalp

The most direct method of use is to apply peppermint oil to the scalp with the use of a carrier oil. You can take your pick from the many options, including:

  • Coconut oil
  • Magnesium oil
  • Almond oil
  • Sunflower oil
  • Jojoba oil

For best results, apply your mixture of oils to the scalp each evening. You can boost results by massaging the scalp during your session.

In fact, scalp massage alone has been shown to play a part in increasing hair thickness (21). This occurs via stretching forces applied to the dermal papilla cells which then may result in favorable gene expression.

How to Massage the Scalp

Place your thumbs and index fingers on either side of your head above the ears. Use a gentle, circular motion to massage the oil into the scalp.

You’ll begin at the sides, then move to the crown, temples, and finally to the base of the skull.

This will improve circulation to the scalp and soften the tissues (21). It will also ensure proper application of the oils.

Use a Dermastamp

While massage has beneficial effects on the scalp, there is another way to increase blood flow and even stimulate the production of new cells – microneedling (22).

Microneedling is a therapeutic technique that uses tiny needles to wound the skin (23). As the wounds heal, a three-step process takes place that stimulates collagen production and new cells:

  • Inflammation
  • Proliferation
  • Maturation (Remodeling)

And while the technique may seem counterintuitive, there are studies that show its use is effective for hair growth. One study even showed it to improve the efficacy of minoxidil (24).

There are two tools that are popularly used for microneedling – the dermaroller and the dermastamp. Both will provide similar results, though the stamp can be easier to target areas of hair loss and to manipulate on the scalp.

The increase in blood circulation to the scalp can also aid in delivering any topical applications, such as PEO, more effectively.

IMPORTANT! Be sure to wait 12 hours following the microneedling session before applying the oil mixture. Otherwise, there will be discomfort such as stinging/burning.

Can Peppermint Oil Treat Hair Loss?

While the studies outlined above may offer some promise, the fact of the matter is that peppermint oil is not one of the mainstream treatments that offers hair loss sufferers a chance at regrowth.

While the oil may contribute to scalp health and even hair growth, it’s not the only treatment option that’s available.

Actually, there other treatments which have been proven to be successful time and again on human subjects. What are they?

Minoxidil

Minoxidil, also known by the brand name of Rogaine, is a topical formulation that was first developed as a treatment for high blood pressure (25). When taken orally, however, the side effects are quite severe and, as such, it’s not recommend as a first line treatment.

But one unexpected side effect that made itself known during trials was that of hair growth.

While the exact mechanism by which minoxidil promotes hair growth is not known, there are a few theories.

First, the drug is a known potassium channel opener, which means it causes hyperpolarization of the cell membranes (26). This may theoretically widen the blood vessels and open the potassium channels to let more blood, oxygen, and nutrients reach the hair follicles.

Another theory is that minoxidil upregulates various genes, including vascular endothelial growth factor (VEGF), to support vasculature and hair growth (27).

And because minoxidil has been FDA approved for use in hair loss sufferers, there are various human studies that highlight its positive effects.

Study: Five-year follow-up of men with androgenetic alopecia treated with topical minoxidil

One such study was performed at Duke University in 1990 (28). It followed a group of 31 men with AGA as they completed four-and-a-half to five years of treatment with 2 percent and 3 percent minoxidil.

The hair growth seen in the men peaked at one year. At this time, it then began to slow. However, the growth results were still significantly improved over the results from the beginning.

Study: Effect of minoxidil topical foam on frontotemporal and vertex androgenetic alopecia in men: a 104-week open-label clinical trial

A more recent study, performed in Germany in 2016, examined the long-term effects of minoxidil foam (29).

The study began with a 24-week period that included randomized, double-blind controls. The second period was 80 weeks in length and all participants received the 5% minoxidil foam formulation.

Hair growth was assessed by researchers at 24, 52, 76, and 104 weeks.

Hair counts and width showed a significant increase between weeks 52 and 76, respectively.

As concluded by the researchers:

5% MTF is effective in stabilizing hair density, hair width and scalp coverage in both frontotemporal and vertex areas over an application period of 104 weeks, while showing a good safety and tolerability profile with a low rate of irritant contact dermatitis.

Minoxidil is available over-the-counter in both topical and foam formulations, and there are also formulations available for women.

Finasteride

The next drug to gain FDA approval in the treatment of hair loss was finasteride, also known by the brand name of Propecia.

Unlike minoxidil, the way in which finasteride induces hair growth is clear: finasteride is a 5-alpha-reductase type II inhibitor which means it reduces DHT levels in the scalp (30). This is beneficial for men with AGA, as sensitivity to DHT is believed to be one of the main causes of pattern hair loss.

In fact, it’s been shown to reduce scalp DHT by 60 – 75 percent as evidenced by scalp biopsies (31).

And similar to minoxidil, there are plenty of human studies that prove positive effects.

Study: Finasteride in the treatment of men with androgenetic alopecia

The results of two one-year studies were published in 1998 that showed the exact effects of finasteride in men with AGA (32).

A total of 1553 men from the ages of 18 to 41 with male pattern hair loss received oral finasteride 1 mg/d or placebo. 1215 of the men then went on to continue in blinded extension studies for a second year.

The men to receive finasteride saw a significant increase in hair count at year 1 (107 hairs), and this continued at 2 years for the men who continued (138 hairs).

On the other hand, the men who received placebo continued to experience progressive hair loss throughout the one-year study.

As concluded by researchers:

In men with male pattern hair loss, finasteride 1 mg/d slowed the progression of hair loss and increased hair growth in clinical trials over 2 years.

Study: Finasteride increases anagen hair in men with androgenetic alopecia

Another study, published in 2001, highlights the effects that the drug has on anagen hair (33).

Hair growth happens cyclically, and there are three stages within in (34). They are:

  1. Anagen – The stage of active growth that lasts anywhere from two to five years.
  2. Catagen – The transitional stage where hair changes from anagen to telogen.
  3. Telogen – The resting stage where the majority of hair shedding occurs.

Drugs such as minoxidil and finasteride work to transition follicles from the telogen to anagen phase so as to promote hair growth.

In the study mentioned above, 212 men between the ages of 18 and 40 received either a 1mg dosage of finasteride daily, or a placebo pill. This continued for 48 weeks.

The number of hairs in anagen phase within a 1cm2 area were counted at baseline, 24 weeks, and 48 weeks.

The baseline counts in the finasteride group showed a total of 196 hairs with 119 hairs in anagen phase (a measure of 62 percent).

As shown by the study, finasteride resulted in a net improvement in the anagen to telogen ratio of 47%. Even further, the researchers stated:

These data support that finasteride treatment results in favourable effects on hair quality that contribute to the visible improvements in hair growth observed in treated patients.

Finasteride is available by prescription only, and there is a higher risk of side effects with finasteride than with minoxidil.

Anti-androgen drugs have been known to contribute to sexual dysfunction, including the inability to get or maintain an erection and loss of ejaculatory volume (35).

The exact rate at which these side effects occur isn’t entirely known, and it’s a bit of a hot button issue (36, 37). But there are ways to reduce the effects if they do occur.

One way is to reduce the dosage of finasteride from the typical 1mg to 0.5mg per day.

Other adverse effects, including a higher incidence of prostate cancer and depression may occur but they have not been definitely linked (38).

Conclusion

Peppermint oil seems to have many benefits, both for general health and hair. This has been shown with a variety of scientific studies, though none of them have been proven on humans at this point in time.

Does this mean that peppermint oil alone can treat hair loss? No.

However, its use alongside other treatments – such as massage and microneedling – may aid in the regrowth process and improve your odds of hair loss reversal. Its many other health benefits, too, may prove beneficial whether you’re looking to regrow your hair or just create a healthier scalp environment.

But that’s not to say that peppermint oil should be used instead of more mainstream options, including minoxidil and finasteride. The truth is there is still very little known about peppermint oil’s ability to aid in hair growth, and it shouldn’t be relied on entirely.