Update on argan oil

• Used traditionally in Northwest Africa for its cosmetic, bactericidal, and fungicidal activity.

• Rich in vitamin E, oleic acid, and linoleic acid, which are believed to contribute to the perceived cutaneous benefits of this vegetable oil.

• Reputed to impart antiacne, antisebum, antiaging, moisturizing, and wound-healing activity, but clinical evidence is sparse.

• In a small study, the nightly topical application of argan oil resulted in a moisturizing effect, and in statistically significant decreases in transepidermal water loss and increases in the water content of the epidermis.

For more than 800 years, native Moroccans and explorers in the region have cited the health benefits of the topical use or consumption of argan oil.¹ The oil, derived from the fruit of Argania spinosa, is a slow-growing tree native to the arid climate of Southwestern Morocco^2-4 as well as the Algerian province of Tindouf in the Western Mediterranean area.⁵ For many years, it was primarily the populations of the Essaouira and Souss-Massa-Draa regions of Morocco that benefited from the production and use of argan oil.⁶ Largely through the efforts of the Moroccan government, as well as cooperating nongovernmental organizations and private entities, argan oil is now also a well-established ingredient on the edible oil as well as cosmetic oil markets throughout the world.⁶

Dr. Leslie S. Baumann

The vitamin E–rich oil has a reputation for imparting antiaging, hydrating, and antioxidant activity to the skin and ameliorating conditions such as acne, eczema, psoriasis, wrinkles, and xerosis,¹² and, in fact, has been used to treat these conditions as well as dry hair,^3,13 hair loss, skin inflammation, and joint pain.³ This column will focus on the topical uses of this botanical that has been dubbed “liquid gold.”¹²

Chemistry

Oleic acid, an omega-9 monounsaturated fatty acid, is abundant in argan oil (43%-49%) and has been found to act as a penetration enhancer by disturbing the skin barrier.^14,15 Linoleic acid, an omega-6 polyunsaturated fatty acid, found in concentrations of 29%-36% in the oil, is integral in the biosynthesis of inflammatory prostaglandins through the arachidonic acid pathway.^4,16 The presence of linoleic acid may help prevent or mitigate inflammation. Linoleic acid is also a component of ceramide 1 linoleate, which is diminished in dry skin. Topical application of linoleic acid can raise ceramide 1 linoleate levels in the skin, thus reducing xerosis.¹⁷ Argan oil also contains the saturated fatty acids palmitic acid (11%-15%) and stearic acid (4%-7%).²

Though argan oil is mainly composed of unsaturated fatty acids (80%),^1,18,19 the unsaponifiable fraction (1%) is replete with antioxidants, including sterols, saponins, and polyphenols.^4,19 The polyphenolic constituents, primarily gamma-tocopherol, which is considered the most efficient among the tocopherols at scavenging free radicals, are thought to account for the antioxidant effects of argan oil.^1,2,18,20,21

Topical uses

Unroasted kernels are used to produce cosmetic-grade argan oil, which is used in moisturizing creams, body lotions, and shampoos.² Although argan oil contains components that have antioxidant and anti-inflammatory features and there are many patents on the use of argan oil in skin care, there is a dearth of published research studies looking at the effect of argan oil–containing skin care products on aging, inflamed, or dry skin. A study by Dobrev evaluated the efficacy of a sebum control cream composed of saw palmetto extract, sesame seeds, and argan oil applied twice daily to the face over a period of 4 weeks in 20 healthy volunteers, 16 with oily skin and 4 with combination skin. All volunteers tolerated the product. A visible sebum-regulating or antisebum efficacy was observed in 95% of the subjects. Clinical evaluation scores and casual sebum levels decreased significantly after 1 month of treatment. Dobrev concluded that this argan oil-containing formulation was efficacious in lessening the greasiness and improving the appearance of oily facial skin.²²

^{By Consultaplantas/Wikimedia Commons/CC BY-SA 4.0}

Shown is Argania spinosa fruit, the source of argan oil.

Early in 2015, Boucetta et al. reported on their study of the effects on skin elasticity of the daily application or consumption of argan oil in 60 postmenopausal women. During a 60-day period, the treatment group of 30 subjects consumed dietary argan oil; the 30 members in the control group received olive oil. Both groups also applied topical argan oil to the left volar forearm. Skin parameters, including gross skin elasticity, net elasticity, and biologic elasticity, improved significantly with both oral and topical treatments. The researchers concluded that argan oil use confers an antiaging effect to the skin through enhanced elasticity.²⁴ Boucetta and another team previously showed that daily consumption or topical application of argan oil in postmenopausal women yielded significant reductions in transepidermal water loss and significant increases in epidermal water content, suggesting that the botanical agent ameliorates skin hydration by reviving barrier function and preserving the water-holding capacity.²⁵ The same team also demonstrated in 30 healthy postmenopausal women that the nightly topical application of argan oil over a 2-month period yielded a moisturizing effect, with statistically significant reductions in transepidermal water loss and statistically significant increases in the water content of the epidermis observed.²⁶

As a cosmetic agent, argan oil, which is popular in France, Japan, and North America, is touted for hydrating and revitalizing the skin, treating acne, and imparting shine to the hair. The therapeutic activities of topical argan oil are reputed to be antiacne, antisebum, antiaging, moisturizing, and wound healing, but such claims are based on traditional uses with only a small body of supportive clinical evidence.^2,27

Generally, argan oil prices are as high as $40/100 mL in the European, Japanese, and American markets.²⁷ Topical argan oil has been characterized as having a brief shelf-life of approximately 3-4 months.^2,28 A 2014 report on a 1-year study of the oxidative stability of cosmetic argan oil by Gharby et al. found that argan oil quality remains satisfactory when stored at 25° C and protected from sunlight, but storage should not exceed 6 months to meet industrial standards. A rapid loss of quality was seen when argan oil was stored at 40° C.²⁹