Proof that Zinc Oxide Shields UV Rays

Knowing that regular zinc oxide was used as a sunscreen many decades ago just isn’t convincing enough to many people that it is an effective sunscreen. You want research, data, proof. I get it. Plain zinc oxide is not currently marketed as a sunscreen so there are no current data or research to my knowledge. Hopefully, that will change. But through some digging, I have found technical proof that conventional zinc oxide is an effective UVA/UVB protector in skin care. In the book, Sunscreens: Development, Evaluation, and Regulatory Aspects, an authority in the cosmetic science industry, one article mentioned an old 1947 publication that disclosed the absorption spectrum for several metal oxides. This valuable article “Zinc Oxide in Face Powders” cited the percentage of light transmitted by ZnO, TiO2, china clay, chalk and talc at various wavelengths. The following values were obtained from powders compressed into 920 nm thick films as considered applicable to face powder use:
UVB wavelengths range from 290 – 320 nm and UVA rays range from 320 – 400 nm. The percentage of light transmissions was much higher, over 50%, for the other metal oxides. These values indicate that ZnO is a better UV protector than TiO2. These data were not for nanoparticles. It pertained to regular zinc oxide for cosmetic use – a 920 nm layer (less than one micron) is not very thick. You do not need to look like a clown to be protected with regular zinc oxide. Aside from diaper rash and other anti-inflammatory ointments, zinc oxide today is commonly found in blush, powders, and eyeshadows. It is one of the three main ingredients in mineral makeup, the latest hype in the beauty market.

I am very close to finishing my sunscreen e-report. I apologize for the delay. Summer, holidays, family, you get the idea. But mainly, I don’t want to put out a half-hearted attempt.

Related articles:
UVB and sunburn
UVA protection
Sunscreen series

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  1. Brian
    Posted October 30, 2009 at 10:28 am | Permalink

    I purchased and read your comon sense guide to sunscreen. I have been formulating and tweaking my sunscreens here and have had some great success with your information as a great foundation!! I had one small issue I was hoping for a bit of guidance on. i am working with a formulation without any water, just oils, butters, wax and zinc. the formula in the bottle smells amazing. The only problem i am finding now is that once applied rubbed in etc, there is a scent that seems to be coming off the skin. it’s slightly different on each person but the consistant theme of it seems to be “sea, kelp, maybe fish, bit of metalic” That is the best way can describe. I have now added bit of essential oil to see though I feel it still comes through under the fragrance off the skin. Is there any insite you can possibly to provide to a. determine what is causing, b. how to correct it. I really appreciate any guidance you can provide! Thanks Brian

  2. Wabi Sabi Baby
    Posted October 30, 2009 at 10:44 pm | Permalink

    I would change the carrier oils. I do not use EOs in any sunscreen recipes as some are photosensitive, i.e. many of the citrus EOs.

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