Home Cosmetic Science Talk Formulating Skin Question about Iron Oxide as Sunscreen


  • Question about Iron Oxide as Sunscreen

    Posted by mcars on March 20, 2017 at 1:10 am

    Is there any minimum concentration of iron oxide to exhibit UV protection?

    Bobzchemist replied 6 years, 6 months ago 6 Members · 9 Replies
  • 9 Replies
  • johnb

    March 20, 2017 at 7:30 am

    Are you sure you want to use iron oxides for this purpose?

    All grades of iron oxide are strongly coloured. Any amount applied to the skin will be visible and possibly/probably unwanted.

    Think carefuly about user acceptibility before you proceed much further.

    Regarding the specifics of your question, I doubt that anyone has investigated the spectrum absorbing qualities of iron oxides for the end uses you intend.

  • JulietK

    March 20, 2017 at 1:10 pm


    Maybe what you mean is zinc oxide?
    Or titanium dioxide?

  • Bobzchemist

    March 20, 2017 at 1:11 pm

    Also, Iron Oxides, due to their color, will likely heat up in intense sunlight. I can’t imagine that this would be pleasant.

  • mcars

    March 21, 2017 at 12:08 am

    i was just planning to add iron oxide for aesthetic purposes as coloring pigment and I was just curious of the minimum conc for protection against visible light

  • Bobzchemist

    March 21, 2017 at 12:18 am

    Back when I was working on formulating standard liquid foundations, we tested all of them for SPF, to see if we could make any claims. Most of the regular coverage formulas had a SPF of 2, the others were zero. All tinted moisturizers tested were zero. High coverage formulas and concealers got about a 4. The SPF results correlated well with the TiO2 levels - iron oxide levels had virtually no contribution to SPF at all.

  • mcars

    March 21, 2017 at 1:05 am
  • oldperry

    March 21, 2017 at 1:37 pm

    Visible light isn’t the problem that sunscreens are solving. SPF is a measure of how well a product protects against UV light.

    Iron oxides also aren’t on the FDA’s list of sunscreen actives.


    March 21, 2017 at 2:29 pm

    WHY not use a mixture of ZnO and TiO2 which are approved.Critical wavelength for UVA (370nm) is easily achieved using relatively low levels of the combination?

  • Bobzchemist

    March 21, 2017 at 9:32 pm

    Perry and Dr. Bob both have a good point. Since even mentioning anywhere that your SPF coverage had anything to do with iron oxides could result in the FDA forcing a recall of your product, why  would you bother?

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