Science

Use coconut oil for curry, not sunscreen

Summer often means more outdoor fun time and more time spent slathering on sunscreen to block ultraviolet (UV) light of various wavelengths.  Many of us pick a sunscreen  based of its sun protection factor (SPF), which reveals a product’s ability to block UVB, a shorter wavelength UV most often linked to skin cancer.  The longer wavelength UVA wreaks its own kind of havoc and “…also increases the damaging effects of UVB, including skin cancer…”.  The Center for Disease Control (CDCrecommends using a “…sunscreen with sun protective factor (SPF) 15 or higher, and both UVA and UVB protection”.

Sunscreen manufacturers use a fairly small set of chemicals to provide UV protection.  These chemicals absorb and/or reflect the UV light of interest.  Zinc oxide, titanium dioxideavobenzoneoctinoxate, octisalate, octocrylene, homosalate3-octanyl salicylate, and oxybenzone are popular choices, being used solo – or in combination – to limit our skin’s exposure to UVA and/or UVA.

coconut oil productWhat if we skip the sunscreen display and head over to the food aisles? Perhaps just use plain ‘ol coconut oil?

The SPF of coconut oil is about 7.1.  This oil’s ability to absorb UV also appears to decrease with increasing wavelength, i.e. it’s probably not providing good protection against UVA.  While coconut oil is popular ingredient in commercial sunscreens, it’s not the ingredient doing the hard work.

Take for instance Alba Botanica‘s Natural Hawaiian Dry Oil Sunscreen, advertised to have a SPF of 15.  This product’s active ingredients homosalate, ethylhexyl salicylate (also known as 3-octanyl salicylate), and octocrylene are providing most of the defense, rather than the oil ingredients such as coconut oil.

What about a sunscreen you’d make yourself?  This “natural homemade sunscreen” recipe, which lists coconut oil and almond or olive oil as ingredients, isn’t getting its purported SPF of 20 from those oils.  Olive olive has a SPF of about 7.5, while almond’s is around 4.7.  Where could the SPF of 20 be coming from?  A classic blocker of UVA and UVB – zinc oxide.

The most popular oils – olive, almond, peppermint, tea tree, lemon, orange, and coconut – simply don’t provide a good level of UV protection.  It’s best to conserve that coconut oil for cooking a delicious curry and use better suited chemicals to protect your skin.

 

Featured image from coconutoil and in-text image from spectrumorganics.

drrubidium

drrubidium

DrRubidium is an analytical chemist that spends her days finding needles in needlestacks. Also a science communicator, she focuses on the the science behind everyday stuff and pop culture.

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5 Comments

  1. August 12, 2013 at 12:45 pm —

    I know Skepchick doesn’t control the ads, but the huge plug for coconut oil at the bottom of the page is funny. My dark-skinned wife loves to use coconut oil, but it is no good for my pasty-white skin.

    • August 13, 2013 at 5:02 pm —

      Yeah, skeptic blogs in general will have wacky ads whenever alt med is discussed.

      But the tl;dr is that foods are, again, foods. Not medicine.

      I’d add a few things:

      1. Avoid tanning beds. Anything that gives you a tan uses ultraviolet rays. Sure, the tanning bed isn’t as powerful as the sun in terms of overall light output, but it’s also only inches from your face. I mean, the fact that I can say “It takes light REAL-LIFE MEANINGFUL AMOUNT OF TIME to get from the Sun to Earth.” says plenty. Remember the inverse-square law. I bring this up because several people I know have previously told me that they use tanning beds to avoid skin cancer.

      2. Dark skin doesn’t make you immune. Less likely to get skin cancer, certainly. Immune, no.

  2. August 12, 2013 at 6:06 pm —

    I work for a company that produces sunscreens. No one in my corner of the business even pretends that botanicals have a thing to do with actual UV blocking – it’s all in the zinc and other ingredients linked above.

  3. October 9, 2015 at 8:05 pm —

    This experiment indicates the opposite of what is asserted in this article. Coconut oil appears to block primarily UVA and not UVB rays, which makes it especially useful for people with very fair skin who want to go out into the sun for 10 minutes or so once per day to get enough UVB exposure to produce adequate levels of vitamin D for health while avoiding the damage accumulated by UVA exposure deeper in the epidermis. This is a very specific case, I know, but relevant to many North Americans who are known nationwide to be vitamin D deficient at rates of about 50%.

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