Lifestyle

Homemade Sunscreens – Are they worth the risk?

Posted on : 31.01.2020

In recent years there has been a surge of interest in more natural, low-waste, low-cost, supposedly safer alternatives to consumer products. Many people have turned to DIY articles on Pinterest and blogging websites for inspiration and while this might be great for making your own home decor, crafts, beeswax wraps or cleaning products, it’s a different story when that product can have a direct impact on your health, as in the case of homemade sunscreens.

 

Why is sunscreen important?

It’s a sad truth that the rate of melanoma is increasing worldwide.[1] Some health bloggers tout this as evidence that sunscreens don’t work, and even go as far as to suggest sunscreens themselves are causing cancer rates to increase.[2] The more likely explanation, however, given that the average age of diagnosis is 60,[1] is that the majority of skin cancer we’re seeing now is simply the consequence of poor sun protection habits of an older generation. There is strong evidence that shows regular use of sunscreen does, in fact, help prevent melanoma and other forms of skin cancer.[3,4] This isn’t exactly shocking news, but with fresh concerns from the media about the safety of common sunscreen ingredients, the DIY option is understandably appealing.

 

How do natural sunscreens compare?

With natural ingredients like carrot seed oil and red raspberry seed oil reportedly offering SPF 25-50 protection,[2] it might seem simple enough to put together an all-natural recipe that guarantees high protection against UV radiation. However, when natural oils were put to the test by researchers from the University of Florida,[5] Vitamin E was the only one that showed any significant UV absorbance, and even that was across a narrow range in the UVB region. It offers no protection against UVA radiation. Surprisingly, there are some fruit and vegetable powders that showed better absorption, typically an order of magnitude higher than the oils, and with a broader range across the UV spectrum. These were, however, significantly lower than any of the traditional UV filters used in commercial sunscreens. For example, the highest absorption from a vegetable powder (purple carrot) was 0.77 Lg-1cm-1.[5] By contrast, traditional UV filters are in the range of 17.0 to 54.7 Lg-1cm-1, more than 20 times higher.[5]

 

More than the sum of its parts

Many of the DIY sunscreen recipes available recommend zinc oxide, a mineral-based UV absorber and reflector that has been used in commercial sunscreens for decades, and some say all you need to do is add zinc oxide powder to your favourite moisturiser to turn it into a sunscreen. There is no question that zinc oxide is an excellent, broad-spectrum UV filter that is also one of the best choices for sensitive skin—if formulated correctly. Commercial sunscreens and lotions are mixed using a special piece of equipment called a homogeniser, designed to create a mixture of very small particles of one liquid suspended in another (e.g. oil droplets suspended in water). Heating a lotion and stirring in a powder with a wooden spoon might seem to create a smooth, even mixture, but the continuous distribution of zinc oxide is critical for its effectiveness. This can usually only be seen at the microscopic level.[6]

Figure 1 – Zinc oxide is mixed in, but the particles form large aggregates, resulting in poor coverage and dramatically reduced SPF.

 


Figure 2 – When Zinc oxide is mixed and homogenised at the correct temperature and during the correct stage of manufacture, the particles are evenly distributed and offer much better coverage.

 

A recipe for sunburn

Researchers looking into the trend of homemade sunscreens called it “a recipe for sunburn” and stated that “social media…becomes dangerous when the information being shared isn’t accurate or complete.”[7] They concluded that, while some oils provide limited UVB screening properties, used alone they do not meet the necessary criteria in terms of photostability, water-resistance and heat tolerance. Commercial sunscreens in Australia are subject to some of the most stringent regulations in the world and are thoroughly tested for safety and efficacy to ensure they provide the advertised level of protection. A recent review of sunscreen compliance by the Therapeutic Goods Administration of Australia found “no compliance deficiencies that concern us in relation to quality, safety and efficacy in every-day use.”[8]

For consumers who would prefer a physical UV blocker rather than chemical absorbers, Ego recommends SunSense Sensitive Invisible, which contains 15% zinc oxide as the only active ingredient, while offering SPF 50+, broad-spectrum protection. It’s a lot easier to find at your local pharmacy than trying to make it at home and risking the UV damage!

 

Always read the label. Follow the directions for use. Avoid prolonged sun exposure and wear protective clothing, hats and eyewear to further reduce risk. Frequent re-application is required.

 

[References]

  1. Apalla Z, Lallas A, Sotiriou E, Lazaridou E, Ioannides D. Epidemiological trends in skin cancer. Dermatol Pract Concept 2017;7(2):1–6.
  2. How to Make Natural Homemade Sunscreen | Wellness Mama [Internet]. Wellness Mama®2019 [cited 2020 Jan 24];Available from: https://wellnessmama.com/2558/homemade-sunscreen/
  3. Green AC, Williams GM, Logan V, Strutton GM. Reduced melanoma after regular sunscreen use: Randomized trial follow-up. J Clin Oncol 2011;29(3):257–63.
  4. Olsen CM, Wilson LF, Green AC, Bain CJ, Fritschi L, Neale RE, et al. Cancers in Australia attributable to exposure to solar ultraviolet radiation and prevented by regular sunscreen use. Aust N Z J Public Health 2015;39(5):471–476.
  5. Gause S, Chauhan A. UV-blocking potential of oils and juices. Int J Cosmet Sci 2016;38(4):354–63.
  6. Klein K. Using zinc oxide in sunscreen products. Cosmet Toilet 2004;119(2):22–25.
  7. Merten JW, Roberts KJ, King JL, McKenzie LB. Pinterest Homemade Sunscreens: A Recipe for Sunburn. Health Commun 2019;1–6.
  8. Australian Government Department of Health Therapeutic Goods Administration. TGA’s compliance review of sunscreens [Internet]. Ther. Goods Adm. TGA2018 [cited 2020 Jan 24];Available from: https://www.tga.gov.au/community-qa/tgas-compliance-review-sunscreens

 

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