Evening Primrose Oil for Hair Growth: Uses And Benefits

  • Medically reviewed by: Dr. Anil Simhadri
  • Written by: William Hartfield
  • Last updated: 07/02/2024

In this article, you’re going to learn about the latest scientific discoveries on using evening primrose oil for hair loss, so you can determine whether it’s the right addition to your hair care routine.

Firstly, I’ll explain what evening primrose oil is, its origins, and its historical uses.

Secondly, I’ll dive into all of the studies that have investigated how effective the oil may be for hair growth.

Thirdly, I’ll outline some potential side effects of use as well as the two main ways you can begin to use the oil yourself.

Let’s get started!

What Is Evening Primrose?

Evening primrose, or Oenothera biennis, is a yellow flower that is found primarily in North America, Central America, and Europe.

Each flower has a short blooming period, and only opens up for one evening (hence the name) before withering and dying the following day. It is said to light up in the dark.

The oil, which is extracted from the seed, is considered to have therapeutic properties. In addition to the evening primrose’s leaves and roots, the Native Americans have used the oil for a wide array of ailments, from minor wounds and bruises to gastrointestinal disorders and hemorrhoids (1).

Evening primrose oil has a primary composition of essential fatty acids such as linoleic acid, gamma-linoleic, and glutamine (2). Linoleic acid is considered an essential omega-6 fatty acid, as our body cannot produce this fatty acid itself.

Omega-6 is necessary for human health. It plays a crucial role in cerebral and nerve functioning, as well as the growth and development of cells. In addition, omega-6 maintains bone health, supports the reproductive system, regulates metabolism, and contributes to healthy hair.

While there is currently limited evidence, evening primrose oil may show promise in counteracting different subtypes of alopecia such as alopecia areata and effluvium telogen. It may also be effective in treating hair loss as a result of hyperthyroidism, or overactive thyroid.

Evening primrose oil, in addition to stimulating healthy skin and hair, has strong anti-inflammatory and antioxidative properties that will nourish the scalp and deliver essential nutrients to promote growth (3, 4).

The Hair Growth Benefits of Evening Primrose Oil

Now let’s look more closely at how the use of evening primrose may be able to slow hair loss, and even contribute to regrowth.

1. Evening Primrose Oil For Hair Growth Phases

Hair growth has three main phases – anagen, catagen, and telogen (5).

  • The anagen phase is the active stage where the cells are rapidly dividing as new hair is forming.
  • The catagen phase is the transitional stage that allows the attachment of the hair sheath to its respective hair root.
  • The telogen phase is the resting stage, where there are no activities in motion. This is the phase when the hairs are naturally shedding. Healthy individuals lose about 25 to 100 hair strands a day.

Recent studies have indicated that evening primrose oil can indeed have a direct effect on hair follicles.

In a study by Munkhbayar et al, the researchers took hair strands from healthy human volunteers between the ages of 20 to 50 years old and measured the effect of arachidonic acid on the elongation of the hair shaft, expression of growth and survival in-vitro, or using isolated human cells (6).

Meanwhile, the researchers applied a mixture of either a placebo, arachidonic acid, or minoxidil every day for four weeks on the shaved backs of female mice.

These mice had just ended the telogen phase and undergoing the anagen phase of growth. The anagen hairs were then examined 28 days later.

Multiple results showed to be very positive. The cells in the dermal papilla were more viable for up to 2 µM of arachidonic acid before decreasing significantly with increased dosage.

There was an increase in fibroblast growth factors and other molecules that stimulate hair production and survival. In addition, the hair shaft resulted in significant elongation at a moderate dose of arachidonic acid.

Meanwhile, the mice that had the arachidonic acid application on their back grew more hair at a faster rate than the mice in placebo or minoxidil groups.

Hair growth in mice using evening primrose oil
Source. A comparison of hair growth in mice between a control, minoxidil and arachidonic acid. (Linoleic acid found in evening primrose oil is a precursor to arachidonic acid.)

The dermal papilla, which is located in the hair follicle’s bulb, is composed of cells that help regulate keratin. Keratin is a protein commonly known for building healthy hair and skin.

The researchers postulated that the arachidonic acid-activated special growth factors encouraged the multiplication and maintenance of these keratin cells during the anagen phase of growth. Arachidonic acid also appears to trigger multiple signals that affect a variety of cell functions (7).

Specifically, important molecular factors for preventing cell death (aka apoptosis or necrosis) are triggered and activated to help promote the survival of growing and existing hair cells.

In addition, arachidonic acid appears to also induce anagen phase. It also extends the duration of the stage, resulting in more cell division before it settles into the catagen phase.

All this not only contributes to ample growth of hair but also stronger and thicker hair strands.

But where does evening primrose oil come in?

Linoleic acid in evening primrose oil is a precursor to arachidonic acid. Your body can take linoleic acid and synthesize it in the liver to eventually become arachidonic acid.

However, it is important to note that based on the results of this study, mild to moderate amount of arachidonic acid will reap the most benefit. Too much will be counterproductive and may induce adverse inflammatory responses.

2. Benefits of Evening Primrose Oil on Scalp Inflammation

Inflammation is a natural defense response of our body to harmful stimuli such as injury to the tissues or allergies (9).

However, uncontrolled inflammatory response is the source of a vast continuum of crippling disorders related to metabolic syndromes and autoimmune.

In individuals with chronic hair loss, unnatural accumulation of substances such as free radicals, DHT, and bacteria in the scalp region ignites an inflammatory response from the body. The symptoms of inflammation, such as itchiness and dryness, will damage the follicles and their respective strands. This will ultimately lead to chronic hair loss, which may become irreversible.

Evening primrose oil can reduce scalp inflammation and itching
Evening primrose oil can help to reduce inflammation, itchiness and flaking which can be a cause of hair loss.

Early studies have postulated that the polyunsaturated fatty acids in the evening primrose oil could be the main derivatives for inflammatory relief.

In this one study, Senapati and his team of dermatologists enlisted young patients with atopic dermatitis and separated them into two groups – one taking 500mg of evening primrose oil and the other taking 300mg of sunflower oil.

After 5 months of continual usage, the researchers compared the results and found that 96 percent of the evening primrose oil users showed substantial improvements, in contrast to only 32 percent of the sunflower oil users.

Like earlier studies, the researchers support the theory that lack of omega-6 fatty acids plays a role in inducing inflammation.

However, they further refine this theory by suggesting that it is not necessarily the lack of linoleic acid (aka omega-6 essential fatty acid) that is the source of inflammatory aggravation, but more likely the reduced conversion to gamma-linolenic acid (GLA) that is the more likely culprit.

While the scientific community has conflicting views, the reduced production of gamma-linolenic acid may be contributing to an increased likelihood of inflammation.

This is primarily because gamma-linolenic acid can convert to dihomo-gamma-linolenic acid (DGLA), which has been shown to fight against specific proinflammatory mediators (11).

Another suggestion for the evening primrose’s anti-inflammatory effects could be related to its sterol qualities. Sterol is a subtype of lipid –cholesterol and sex hormones (estrogen and testosterone) falls into this category.

Evening primrose oil has a high composition of phytosterol or plant sterol. This sterol is naturally found in many plant-based foods such as grains, vegetables, fruits, and nuts.

Plant sterol is well known for its cholesterol-lowering effects, which are correlated with reduced inflammation (12).

A common belief for this phenomenon is due to the similar chemical composition of plant sterol and cholesterol. When there is too much LDL, or bad cholesterol, it will seep into the walls of the artery and damage the lining by forming plaque.

This will instigate an inflammatory response, which only worsens as an accumulation of cholesterol further aggravates the site.

Because plant sterol has a similar structure to LDL, it will act to directly block LDL’s absorption. In fact, a study where people drank sterol-fortified juice found that in two weeks alone, their LDL cholesterol level dropped an average of 12.4 percent.

Paz et al suggested an additional theory for plant sterols’ effect on inflammation by focusing on the mediators (13). In their study, the largest composition of plant sterol from the evening primrose oil, beta-sitosterol, and campesterol, were extracted and cultured with mice cells.

The researchers took several inflammatory markers, such as macrophages, nitric oxide, and prostaglandins, and tested each of them with 25, 50, and 100 g/ml of sterol in the cell culture.

The results found that a number of inflammatory markers were notably reduced, with many of them to a significant degree.

For example, the reduction of nitric oxide (NO), which plays a key role in inflammatory and immune reaction activities, was at its greatest in the 100 g/ml plant sterol culture.

In addition, the researchers postulate that the plant sterol helped prevent linoleic acid from converting into the polyunsaturated omega-6 chemical arachidonic acid.

Though we mentioned above that it could directly help with hair growth, an excessive amount of this particular omega-6 fatty acid has been thought to initiate and amplify inflammatory reactions. This will only counteract the potential benefits that arachidonic acid can have on the process.

3. Evening Primrose Oil and Antioxidant Vitamin E

Free radicals attack important molecules leading to cell damage and disruption. Targets of free radicals include all kinds of molecules in the body such as lipids and proteins.

Once a cascade of cell damage has erupted within a site, such as at the scalp, the body will initiate an inflammatory response to stop the damage and start repairing the cells. However, chronic inflammation will ensue if the free radicals are not dealt with properly.

Early studies have postulated that chronic hair loss may be attributed to unmanageable free radicals and lower levels of antioxidants in the scalp area, leading to high oxidative stress (14).

Antioxidants prevent free radicals from causing damage by donating one of their electrons. There are likely thousands of different antioxidants to manage different subsets of free radicals.

Among the many antioxidants in the evening primrose oil, one of the more abundant is Vitamin E.

An antioxidant donating an electron to a free radical
Vitamin E found in evening primrose oil may help reduce oxidative stress from free radicals in the scalp thereby reducing hair loss and stimulating hair growth.

Vitamin E is a fat-soluble antioxidant known for its ability to build and repair tissues (15). Vitamin E is also a potent radical-scavenging antioxidant that is most well known for acting as an inhibitor for lipid peroxidation, or degradation of the lipid, caused by free radicals.

The chemical structure of Vitamin e
Vitamin E found in evening primrose oil may help reduce oxidative stress from free radicals in the scalp thereby reducing hair loss and stimulating hair growth.

To demonstrate Vitamin E’s correlation with preventing hair loss, researchers Beoy et al took 38 healthy males and females with varying levels of alopecia were split into either taking a placebo supplement or tocotrienol (a member of the Vitamin E family) supplement for eight months for a total of 100 mg a day (16).

Hair count and weight of hair were collected and measured.

The results showed that the hair numbers at the 8-month interval were significantly greater than those at baseline and the 4-month interval for the Vitamin E group.

Mean hair numbers after 8 months supplementation with Vitamin E

Mean hair numbers after 8 months supplementation with Vitamin E
Source. Hair numbers

In contrast, the placebo group displayed very little growth at the 8-month mark (so, supplementation with vitamin E wins by 35 percent).

Unfortunately, this study did not find any statistical difference in the weight of hair strands.

Mean hair weight after 8 months bit E supplementation
Source. Hair weight

The researchers also mentioned that in addition to acting as a vital antioxidant, Vitamin E may be able to increase blood vessel growth, therefore increasing the number of nutrients that reach the cells of the follicles.

The sebaceous gland, as seen in a model of the hair follicle.
Blood flow to the hair follicles is incredibly important for the survival of the hair.

It also efficiently increases the removal of waste that would otherwise cause damage to scalp tissues. This will encourage rapid hair growth and the healing of damaged hair shafts.

How to Use Evening Primrose Oil Treatment

There are two ways you can go about adding evening primrose oil to your daily hair care routine.

As a Supplement

Evening primrose oil can be taken as an oral supplement. It is sold in capsule or soft gel form. Each capsule generally contains 1000mg. Talk to your doctor about the best dosage based on your circumstances.

As a Topical Application

One of the more effective methods of utilizing evening primrose oil is directly applying it to the scalp. It can better penetrate the pores and deeply nourish the hair and its follicles.

You can have it deep conditioned by leaving it overnight on the scalp and washing it off in the morning.

For an even more effective use of the oil, you can also combine it with scalp stimulation techniques such as massage and microneedling.

Both massage and microneedling work to increase blood flow to the scalp, while simultaneously reducing inflammation (17, 18). Both of these techniques have even been proven to have positive effects on hair growth in those with male-pattern baldness (19, 20).

Potential Risks and Side Effects

Though the oil does not contain many side effects, it may interact negatively with certain medications. According to the National Institutes of Health, you should use with caution if you are taking the following (21):

  • Anticoagulant and antiplatelet medications: There is an anticoagulant (blood-thinning) effect with evening primrose oil so there is a higher risk of bleeding for people taking any blood thinner such as warfarin (Coumadin). Therefore, these patients should not use the oil.
  • Simvastatin and niacin: Antioxidants such as evening primrose may blunt the beneficial effects of cholesterol medications by blocking the response of HDL (the ‘good’ cholesterol) (22).
  • Chemotherapy and radiation: Antioxidants work within the body to prevent oxidation and, as such, their use can reduce the effectiveness of these therapies by inhibiting cellular oxidative damage (23).

If you’re pregnant or nursing, it’s best to speak with your obstetrician before using (or continuing) evening primrose.

If you suffer from any chronic medical conditions, or if you are taking medications not mentioned above, it’s also a good idea to consult with your physician before you begin supplementation.


As with any ‘natural’ hair loss treatment, evening primrose is not a cure-all for hairline recession and balding. Its various beneficial properties as a result of its high essential fatty acids content may contribute to lessening hair loss and perhaps even promoting regrowth.

This is especially true when the oil is combined with scientifically proven techniques such as massage and microneedling.

But the truth is, that the best way to treat hair loss is by addressing the underlying issue. This will vary from person to person, and it may be necessary to consult with a dermatologist to learn the true cause (and available treatments) for the problem.

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