What is coconut oil?
Coconut oil is a mix of fats extracted from coconuts. There are two major ways to produce coconut oil: wet and dry processes. To obtain coconut oil in the wet process, the white part of the coconut called the “flesh” or “meat” is removed from the outer husk. Following this step, the coconut meat is cold-pressed to create a white semi-transparent coconut milk. The coconut milk is allowed to ferment for a few days which allows the oil to be separated from the milk and recovered. This process of isolating coconut oil in this way is described as “virgin coconut oil”. In other instances, coconut oils are extracted from coconuts using various chemicals or heat. The primary oil present in coconut oil is called lauric acid and typically in quantities ranging from 45-53%.
How is coconut oil used?
Coconuts have been used in many cultures as both a food and medicinal plant for centuries. Today, extracted coconut oils are used as industrial lubricants, fuel for combustion engines, livestock feed, and also as a cooking oil. Other uses include ingestion as a dietary supplement, addition to haircare products, and application to the skin.
Coconut oil and hair
There are a variety of coconut-based cosmetic preparations developed for hair. They include conditioners, shampoos, and oils. Does the addition of coconut oil actually make the hair stronger? Well, one study compared mineral oil, sunflower oil, and coconut oil in the prevention of hair damage. The authors studied protein loss in hair after using the three different oils in pre-wash and post-wash products. After their analysis, they showed that coconut oil helps reduce protein loss1. However, it is difficult to assess whether this means that it actually strengthens the hair, reduces breakage, and makes hair feel softer. There are many important components to hair strength and texture which include the bonds between the building blocks (amino acids) in hair, natural hair structure, microscopic characteristics, pH balance, and the cleaning detergent composition of the product applied.
Does coconut oil have any antibacterial activity?
Various studies have shown that the major component in coconut oil (lauric acid) has antibacterial activity2. If is effective against a number of bacteria including those which typically overgrow on the skin and may cause skin ailments. The two most common culprits are the bacteria Staphylococcus and Streptococcus. Lauric free fatty acids have also been shown to reduce the growth of the bacteria (P. acnes) which is implicated in acne3. It is unknown whether this translates into improvement of the human skin since these studies have not been performed. Many factors contribute to the development of acne and overgrowth of P. acnes is just one factor.
Coconut oil and severe dry skin
Similar to haircare products, there are also a variety of skincare products that are coconut based. Many claim to have natural moisturizing factors but are these true? Unfortunately, they have not been shown to definitively improve dry skin when compared to some traditional moisturizers. An excellent high-quality study has been conducted comparing mineral oil to coconut oil. It was used for severe dry skin (called xerosis) in a Dermatology clinic located in the Philippines4. They had 34 subjects who suffered from severe dry skin on the legs and were instructed to apply the two different oils for 2 weeks and were re-evaluated at the end of this period. In the end, both oils improved the dry skin equally.
Coconut oil and atopic dermatitis (also known as eczema)
Scientists have conducted a similar study as the dry skin reference above, but the study was larger study, and in children 1-13 years of age. All of these children were diagnosed with atopic dermatitis also known as eczema5. Again, mineral oil was compared to coconut oil after 8 weeks of application. In this case, coconut oil was found to be superior to mineral oil but both moisturizers improved the skin. The coconut oil group achieved moderate improvement in 47% of the patients and excellent in 46%. The mineral oil group achieved moderate improvement in 34% and excellent in 19% of the subjects. They used a standardized evaluation tool for eczema called SCORAD (SCORing of Atopic Dermatitis) to compare the treatments. A special tool that analyzed how well the skin barrier functions (called transepidermal water loss) verified their clinical results. The skin functioned better in the coconut oil group compared to the mineral oil group using this instrument to measure the change. For more information of prevention of dry skin and eczema, please visit our section on dry skincare tips.
Coconut oil and psoriasis
Unfortunately, not many studies have investigated the use of coconut oil in psoriasis. There is, however, one small study which has been published specifically looking at this exact topic6. Coconut oil was applied before phototherapy (narrow-band UVB) and did not show improvement. Their conclusion was that pre-application of coconut oil before phototherapy does not seem to have a benefit.
Coconut oil and seborrheic dermatitis
To date, no clinical studies have been completed using coconut oil for treatment of seborrheic dermatitis or dandruff. One publication examined the growth of the yeast (Malassezia) in the laboratory setting. In their study, the natural fats present in coconuts allow for the growth of the yeast7. As you many already know, the overgrowth of this natural body yeast has been implicated as a cause of seborrheic dermatitis. For more information on the causes of seborrheic dermatitis, we encourage you to visit this section of our website.
A clinical study performed in India showed increased growth of Propionibacterium and Malassezia following coconut oil scalp massage8. They were primarily looking at the scalp microbiome as none of the subjects actually had seborrheic dermatitis so increased flareups was not reported. The skin microbiome is extremely important as different ratios of Malassezia and even an newly discovered species of Malassezia is associated with severe cases of seborrheic dermatitis9.
There has been one study which evaluated Borage oil in seborrheic dermatitis which is high in gamma-linolenic acid. This molecule has some similarities to lauric acid (the major component found in coconut oil) as they are both fatty acids but they are quite different in overall structure. In this case it was shown to improve infantile seborrheic dermatitis10.
Coconut oil and the skin
In summary, a variety of high-quality studies have been conducted to evaluate the effectiveness of coconut oil on the skin and hair. Coconut oil seems to have some antimicrobial effects, reduces protein loss of the hair, improves atopic dermatitis or eczema, seems to be as good as mineral oil in severe dry skin, but has not been shown yet to improve psoriasis when combined with phototherapy. Given processed coconut can be used as a growth media for the Malassezia, using this on areas prone to seborrheic dermatitis could theoretically cause flareups. That being said, no studies exist to confirm this hypothesis.