28 Day Study Of Olive Oil For Hair Growth: A Scientific Review

  • Medically reviewed by: Debra Rose Wilson, PhD MSN RN IBCLC AHN-BC CHT
  • Written by: William Slator
  • Last updated: 25/01/2024

Between genetic hair loss and the ill effects of daily living, the hair (and scalp) can take quite a beating. But whether you are looking to prevent breakage and hair loss, or treat and reverse its effects, olive oil could be the answer you are looking for.

This article will discuss the possible benefits of olive oil for hair growth and maintenance.

You are going to learn about the scientific study carried out on oleuropein (found in olive oil) which showed it was more effective than minoxidil at regrowing hair. You will also understand the mechanisms that are likely behind these results, and how you might be able to get the same benefits.

Olive oil DIY hair recipes

Olive Oil as a Food & Medicine

Olive oil is a staple food in most of the world. It is derived from pressing olives. About 70% of worldwide production originates from Mediterranean countries like Greece, Italy, Spain, and Turkey.

Beyond its use in the kitchen, olive oil is important in the cosmetics industry and has been used medicinally for thousands of years (1,2).

This is partly because it is rich in fatty acids and antioxidants. Its antioxidant properties, in particular, might be partly responsible for its putative hair growth effects.

Nowadays, an ever-increasing number of people are turning to olive oil as part of their hair care routine. From its ability to moisturize the scalp to its use as a hair growth stimulator, is this reputation justified (3)?

Olive Oil and Hair Growth

To understand what follows, we first need a brief overview of the hair growth cycle. This has three phases (4).

The Hair Growth Cycle

Anagen – This is the phase of active growth and rapid cell division. Hair only grows out during anagen.

Catagen – This phase is brief and signals the end of active hair growth.

Telogen – This phase is the resting phase, where shedding typically occurs. Healthy individuals will typically lose 25 – 100 telogen hairs per day.

Hair growth phase is important to understand the reasons behind hair loss

In individuals who suffer from androgenetic alopecia (pattern baldness), the anagen phase of the hair growth cycle significantly shortens.

As the length of the hair shaft is proportional to the length of the anagen phase, the briefer this phase, the shorter the hair shaft. Eventually, balding men are left with hair that is too short to poke through the scalp.

Oleuropein vs Minoxidil

Oleuropein is a polyphenolic compound found in the leaves of the olive tree, as well as in olive oil. Recently, a team of Korean researchers found that it induces anagen hair growth in telogen mouse follicles (5).

The researchers split 24 mice into three groups of eight. The backs of the mice were shaved at 8 weeks of age, which had the effect of synchronizing all their hairs into telogen.

For 28 days, each mouse received a 200 μL topical application of either control solution, control plus 0.4mg of oleuropein, or control plus 3mg of minoxidil.

The researchers photographed the mice on days 0, 7, 14, 21, and 28. They also measured 10 random hairs from each mouse on the same schedule.

Mice hair growth results using olive oil constituent
A comparison of hair growth in mice being treated with either A. a control; B. oleuropein; or C. minoxidil. Source.
Oleuropein hair length mice
A comparison of the hair length (in cm) of mice treated with a control, oleuropein, or minoxidil. Source.

Unsurprisingly, the hairs in the oleuropein-treated group were longer than those in the control group. More surprising was the finding that the oleuropein-treated group also had better results than the mice in the minoxidil-treated group.

These results were likely due to oleuropein increasing the expression of various growth factors. Oleuropein also led to the modulation of the Wnt10b/β-catenin pathway.

This pathway, proven to prolong the anagen phase, is largely responsible for the significant hair growth seen in the mice (6).


Effects on the Hair Shaft

While the above study showed very interesting results, it is important to emphasize it was on mice, not humans. Results from animal studies are often notoriously difficult to replicate in humans.

Most people who use olive oil on their hair do not even apply it to the scalp. Instead, they use it to treat the hair shafts only. When used like this, olive oil has several benefits.

1. Moisturizes Hair & Reduces Breakage

According to experts, massaging your hair with olive oil can help seal the moisture into the hair shafts. This will lead to more volume, less breakage, and frizz. It will also keep your hair more soft and pliable. Another important benefit is that it will reduce breakage.

2. Prevents Split Ends

For those with longer hair, as well as those who want to grow out their hair as quickly as possible, split ends can be a major problem. One of the most common benefits users of olive oil report is that it prevents split ends.

Celebrities & Olive Oil

Many celebrities swear by olive oil for their hair. For example, former model Jerry Hall has used olive oil once a week for decades. She credits it with keeping her hair soft and supple and allowing her to wear it long well into her 60s.

Julia Roberts has also publicly stated that she uses olive oil on her hair (as well as her skin and nails). Miranda Kerr also applies an olive oil mask once a week, and she credits it for leaving her hair “extremely shiny”.

Side Effects & Other Considerations

Olive oil is very safe for humans, and when applied topically it has virtually no side effects. Like with any other substance, a very small percentage of people will be allergic to olive oil. Those with allergies may develop a skin rash similar to eczema and should cease use immediately.

If you have problems with dandruff, you might also want to consider other treatments for your hair. Olive oil can directly feed Malassezia, the fungus scientists believe is responsible for most cases of dandruff.

In that case, applying it to your scalp will likely lead to itching and eventually full-blown dandruff.

Topical olive can also be very messy. Especially if you have long hair, it will take some time to massage the oil into your hair shaft, and then even longer to rinse it back out.

How to Use It  for Hair Loss

The easiest way to use olive oil is to apply it directly to your scalp.

  • Pour a quarter-sized amount of olive oil into your palm.
  • Rub your palms together to distribute the oil.
  • Using your fingertips, begin to massage the oil into your scalp.
  • As you work, slowly massage the oil down the hair strands from root to tip.
  • Continue until the oil is evenly distributed throughout the scalp and hair.

You can also combine olive oil with other oils, like castor and almond oils, for even further benefit.

A traditional hair mask involves combining olive oil with egg yolk, which is especially rich in proteins. To prepare this mask, you can whip 2 egg yokes into four tablespoons of extra virgin olive oil. Massage it into your scalp as above.

If you don’t want to apply olive oil on your scalp, you can simply oil your hands and run them through the hair shafts. Pay special attention to the edges, as this is the part of the hair shaft that will get the most benefit from the treatment.

The Best Kind of Olive Oil for Your Hair

Before you start treatment, you want to be sure you are using the right kind of olive oil. There are many different kinds of olive oil on the market.

For the highest quality, you should use unrefined, cold-pressed extra virgin olive oil.

Refined Versus Unrefined

When shopping for olive oil, you will see one of three processing methods on the label: refined, unrefined, and cold-pressed (7).

The refining process uses chemicals and/or heat to remove impurities after extraction. This may also introduce other oils, like canola and vegetable oil, into the finished product.

Alternatively, unrefined oils are produced without chemicals or heat. The oil is simply filtered and decanted. This results in clean, higher-quality oil.

Cold-pressed oils are also a type of unrefined oil, where the temperature during the extraction process never climbs above 27.2 degrees Celsius. This ensures it preserves all its compounds and aromas. Olive oil dressing

Light Versus Virgin Versus Extra Virgin

If you look closely at the various olive oils at the supermarket, you will notice significant color differences. This all comes down to whether they are a light, virgin, or extra virgin. These are just another name for refined versus unrefined.

Light olive oil is refined. Its light yellow color is a result of the extensive refining process. These oils have the least amount of nutrients due to the heat and chemicals involved.

Virgin and extra virgin olive oils are types of unrefined oils. The distinction between the two comes from the level of impurities and overall quality.

These oils are both processed the same way, with expeller and/or cold-pressing methods. Once the sediment settles to the bottom of the oil, the rest of the oil is processed into batches.

Extra virgin olive oils must meet specific industry standards to earn this label. These include numerous chemical and sensory (aroma, flavor) standards. As such, extra virgin olive oil is the highest quality of the two.

Whether due to the quality of the olives or a relaxed processing method, virgin olive oil will fall short of the industry standards required of extra virgin olive oil. The aroma and flavor may be slightly flawed.

Is Olive Oil the Treatment You Are Looking For?

There are a few studies that suggest olive oil may play a role in hair and scalp health, and possibly even promote hair growth.

Topical application of olive oil may certainly have its benefits, but it is unlikely to treat your hair loss condition by itself. To do this, you will need to fix the underlying cause of your thinning and loss. Only once you are addressing the problem directly will you see favorable results from such treatments as olive oil.

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