All About Zinc Oxide

The scientific basis of Apoptosis Protection Factor [APF]: Zinc Oxide

*Zinc Oxide [ZnO] acts as a physical block that scatters UV light and stops it from reaching the surface of the skin.

The graph below shows how this active ingredient absorbs light in the UV A and B ranges. The left side of the graph shows how much light is blocked by the zinc oxide. The bottom of the graph shows the UV wavelength at which it is being tested. The different sets of points or lines on the graph represent different concentrations at which the ingredient is being tested:

*The optimal concentration range for the zinc oxide is .7 – 7.5%; below the minimum value, the activity of this ingredient may not be optimal and may not provide significant UVA and UVB apoptotic sunburn protection; above the maximum value, although the activity of the test compound is retained, there are other consumer factors to consider such as colour and consistency.

This type of study is known as an Absorbance Graph that measures the amount of light passing through a substance (zinc oxide in this case). Some sunscreen ingredients may not be subjected to this rigorous type of scientific test to measure how much UV light they are stopping from reaching the skin’s surface. This is the special test for determining Apoptosis Protection Factor {APF} in all Moondust Natural Suncare Products. Individually, an acceptable reading lies between Level 1and 4 for an active ingredient. The higher the reading on the scale from 0 to 4, the greater the amount of UV light that is being blocked.

Please see Table 1 below:

Table 1.  UV Absorbance Readings of Zinc Oxide:



 Zinc Oxide2.752.875

Zinc oxide provides a reading of Level 2.75 in the UV A range; and Level 2.875 in the UV B range.

These readings show that zinc oxide is a good sunscreen that is blocking light at nearly Level 3 or three-quarters of the maximum reading value in both UV A and UV B ranges.