Helianthus annuus (sunflower) seed oil is used in a variety of cosmetics and personal care products as an emollient. It also provides benefits such as decreasing inflammation, replenishing the skin’s barrier, and improving hair loss conditions.
Helianthus annuus is the name of the plant species commonly known as the sunflower. Sunflower seed oil is the non-volatile oil pressed from the seeds of sunflower. All Helianthus species are native to North America, except for three species in South America. Sunflower seed oil can be extracted using chemical solvents (i.e., hexane), or expeller pressing (i.e., squeezed directly from sunflower seeds by crushing them). The world’s total production of sunflower seed oil in 2014 was nearly 16 million tons.
Sunflower seed oil is a mixture of monounsaturated and polyunsaturated fatty acids, consisting of approximately 59% linoleic acid, 30% oleic acid, 6% stearic acid, and 5% palmitic acid. The oil also contains significant quantities of vitamin E, sterols, and squalene. In addition to use in cosmetics, sunflower oil is available as a cooking oil. It is known for having a clean taste and low levels of trans fat.
In cosmetics and personal care products, sunflower seed oil primarily functions as an emollient, which is why this ingredient is often added to creams, lotions, and hair care products.
As an emollient, sunflower seed oil works to soften and soothe the skin while also acting as an occlusive agent. Upon application, occlusive agents form a protective film on the surface of skin. This film helps to prevent evaporation of the skin’s natural moisture and increases skin hydration by causing buildup of water in the stratum corneum (the uppermost layer of skin).
Sunflower seed oil is also commonly used in hair conditioners and other hair products due to its emollient properties. In fact, it is the second most common base oil used in the hair oil industry, according to the Journal of Cosmetic Science. Sunflower seed oil has a softening effect on the hair and helps to prevent breakage.
The fatty acids found in sunflower seed oil help to restore the skin’s natural barrier function. A 2013 study examined the effects of sunflower seed oil on the adult skin barrier and found that the oil preserved stratum corneum integrity, did not cause erythema, and improved hydration in the volunteers. The stratum corneum is composed of corneocytes (dead skin cells) held together by a lipid barrier. In addition to fatty acids, the barrier consists of ceramides and cholesterol. A deficiency in these essential lipids can lead to a weak or damaged barrier, which can subsequently allow harmful things like allergens, bacteria, and irritants to pass through the skin. This results in symptoms of dryness, itching, and irritation, and may lead to the development of skin conditions like acne, eczema, and even signs of aging. Using ingredients that replenish the skin’s barrier, such as sunflower seed oil, can help to prevent these problems.
Sunflower seed oil provides anti-inflammatory effects due to its high composition of linoleic acid. Linoleic acid hydrates the skin and improves elasticity, and also has an effect on certain inflammatory mediators. The anti-inflammatory properties of sunflower seed oil make this an excellent ingredient for those with symptoms of dry, flaky, or irritated skin.
The linoleic acid found in sunflower seed oil is also thought to improve hair loss conditions by increasing blood circulation and improving skin penetration for topical hair growth treatments. Studies have found that linoleic acid may also be able to block the formation of DHT, a hormone that is linked to hair loss.
The safety of Helianthus annuus (sunflower) seed oil has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. This ingredient was included in the Panel’s review of plant-derived fatty acid oils. Based on a history of safe use in food, the composition of the oil, and data indicating this ingredient was not a dermal irritant or sensitizer, the Panel concluded that Helianthus annuus (sunflower) seed oil was safe as used in cosmetic products.
References: Wikipedia, “Sunflower oil”, Pediatr Dermatol. 2013 Jan-Feb;30(1):42-50, Int J Mol Sci. 2018, 19(70), Cosmetic Ingredient Review, “Safety Assessment of Helianthus annuus (Sunflower)-Derived Ingredients as Used in Cosmetics” 2016.