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

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Between genetic hair loss conditions 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, you may be interested to know that olive oil could be the answer you are looking for.

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

You are going to learn about the scientific study carried out on oleuropein (found in olive oil) which showed it was more effective than the leading topical hair loss product at regrowing hair. You will also learn why these results likely occurred, and how you might be able to receive the same benefits.

What is Olive Oil?

Commonly used in the culinary arts as a frying oil or salad dressing, olive oil is an oil obtained from the olive crop. This highly-valued tree crop, originating from the Mediterranean Basin, is made into oil through the process of pressing.

Beyond its use in the kitchen, olive oil has made a name for itself in the cosmetics industry and has been used medicinally for thousands of years (1).

From the banks of the Nile to the birthplace of democracy, olive oil has enjoyed a high status and widespread usage (2).

And now, as more individuals are turning to natural and organic cures for their ills, olive oil is being celebrated as a miracle of sorts — from its ability to moisturize the scalp to its use as a hair growth stimulator (3).

Olive Oil and Its Direct Impact on the Hair Growth Cycle

A recent study performed by Tong, Kim, and Park shows that oleuropein, a component found in the leaves of the olive tree, induces anagen hair growth in telogen mouse skin (4).

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There are three phases within the hair growth cycle (5).

Phase 1, Anagen – This is the phase of active growth and rapid cell division.

Phase 2, Catagen – This phase is transitional and allows for the newly-grown hair sheath to properly attach to its root.

Phase 3, Telogen – This phase is known as the resting phase, where shedding typically occurs. During this phase of the cycle, healthy individuals will lose 25 – 100 hairs per day, on average.

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

In individuals who suffer from alopecia, the anagen phase of the hair growth cycle significantly shortens over time.

As the length of the hair is proportional to the length of the anagen phase, the shorter the phase becomes, the shorter the hair which is produced. Eventually, those with alopecia are left with hair which is too short to poke through the hair follicle, leading to thinning and baldness.

In this particular study, 24 mice were split into three groups of eight. The backs of the mice were shaved at 8 weeks of age, and the telogen phase of the hair growth cycle was confirmed.

For 28 days, each mouse received a 200 μL application of either control, control plus 0.4mg concentration of oleuropein, or control plus 3mg concentration of minoxidil. The control consisted of 50 percent ethanol, 30 percent water, and 20 percent propylene glycol.

The mice were photographed on days 0, 7, 14, 21, and 28, and 10 random hairs from each mouse were measured 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.

It is no surprise that the hairs in the oleuropein-treated group were longer than those in the control group. However, it is surprising that the oleuropein-treated group also had better results than the mice in the minoxidil-treated group.

Upregulation of Growth Factor Gene Expression

At the end of the 28-day study, skin samples of the mice were examined.

In the oleuropein-treated group, the mice had a significant increase in the mRNA levels of four separate growth factors (insulin-like growth factor – 1, hepatocyte growth factor, vascular endothelial growth factor, and keratocyte growth factor). In fact, compared to mice treated with only the control, the mice in the oleuropein-treated group saw a 71 percent increase in dermal IGF-1 levels.

Each of the mentioned growth factors plays its own role in the growth and development of hair follicles. IGF-1, for example, is known to regulate cell proliferation which occurs rapidly during hair follicle formation (6).

There is no doubt that the upregulation of growth factor gene expression played a significant role in the study’s results, but there is another reason that treatment for hair growth proved to be so effective in the oleuropein-treated group of mice.

Stimulation of Wnt10b/β-Catenin Signaling Pathway

In a 2010 research study published in Developmental Cell, it was discovered that deletion of the β-catenin gene in dermal papilla cells of fully developed hair follicles led to the premature induction of the catagen phase in mice (7).

Further, the Wnt10b/β-catenin signaling pathway seems to play a role in the maintenance of the anagen phase.

In the oleuropein-treated group of mice mentioned in the previous study, researchers found that not only was there an increase in the mRNA levels of different growth factors, but 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 (8).

Scalp Inflammation and Olive Oil

Certain forms of alopecia are caused by inflammation of the scalp. This inflammation can be caused by a weakened immune system, allergies, or any other number of circumstances (9). Whatever the source of the inflammation, the fact remains that chronic inflammation can be damaging to the hair follicles and induce premature hair thinning and loss (10).

The daily ingestion of virgin olive oil leads to a decrease in circulating concentrations of interleukin-6, a known pro-inflammatory, and C-reactive protein, a responsive protein that indicates inflammation within the body (11, 12, 13).

Oleocanthal, a phenolic compound within virgin olive oil, seems to be the underlying reason for olive oil’s effective treatment of inflammation and inflammatory diseases (14).

Phenolic compounds can be found within a number of plant-based foods, such as chili peppers, oregano, and sesame seeds. Oleocanthal, however, is unique to virgin olive oil, and its various components are present within its very name (oleo – olive; canth – sting; and al – aldehyde). This unique compound is responsible for the irritating sensation felt by most individuals in the back of the throat when olive oil is directly consumed.

Interestingly, this very attribute is believed to be felt most strongly in individuals who are particularly sensitive to the positive effects of oleocanthal.

And, while this phenolic compound is structurally dissimilar to Ibuprofen, the non-steroidal anti-inflammatory drug, both compounds inhibit the very same enzymes in the prostaglandin-biosynthesis pathway which triggers inflammation (15).

As a natural inhibitor of cyclooxygenase enzymes, there is no wonder that oleocanthal plays such a large role in the reduction of inflammation.

As previously discussed, oleocanthal reduces the circulating concentrations of interleukin-6 and other inflammation-causing enzymes. This means that the anti-inflammatory effects are seen throughout the body, which makes oleocanthal a viable option for individuals looking to reduce scalp inflammation and irritation.

Are There Side Effects Associated with Olive Oil Supplementation?

While side effects associated with olive oil supplementation are few and far between, there are those individuals who may need to consult with their doctor prior to supplementation.

Such individuals include those with hypo/hyperglycemia, low blood pressure, and those currently taking high blood pressure medications. The consumption of olive oil can lower both blood sugar and blood pressure, and even with the consent of your physician, individuals low blood pressure should monitor their levels closely (16, 17).

Contact dermatitis, or an allergic skin reaction, is rare. However, those with allergies may develop a skin rash similar to eczema and should cease supplementation immediately (18).

As always, women who are pregnant or nursing should consult with their obstetrician to ensure the safety of supplementation.

How to Use Olive Oil for the Treatment of 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.

The Best Kind of Olive Oil for Your Hair

If you will be going the topical route, you will 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 an unrefined, cold-pressed extra virgin olive oil.

Refined versus Unrefined

There are three processing methods for oils, including olive oil. They are refined, unrefined, and cold-pressed.

The refining process involves the use of 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 during this process, which results in clean, higher-quality oil.

Cold-pressed oils are also a type of unrefined oil, as they are processed without chemicals or heat. Once the oil is extracted from the olive, the olive oil will be set to cool so the sediment settles at the bottom. Thus the impurities are removed with very minimal processing.

Light versus Virgin versus Extra Virgin

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

Light olive oil is refined. The name refers to its light yellow color which is a result of the extensive refining process. These oils have the least amount of nutrients due to the heat/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 — using 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 be labeled as such. 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 which suggest olive oil may play a role in hair and scalp health, and possibly even promote hair growth.

Olive oil supplementation may certainly have its benefits, but it is very 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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