Zinc oxide works so incredibly well as a sunscreen because it is a physical barrier between your skin and the sun. Its sits on top of your skin and prevents the suns UV rays from dmaaging your skin. Using non nano Zinc Oxide which means its has larger molecules makes sure that the Zinc oxide does not absorb into the skin.
Most sunscreens that use nano particles ingredietns are very toxic to the body and disrupt the endocrine system. Your endocrine is your hormonal system. Adrenals for energy, Thyroid for metabolism, pituitary for stress regulation. Sexual Organs influencing your vitality and libido. Absorbing toxic ingredietns into your body through your skin, these ingredietns disrupt and inhibit the function of your endocrine system.
Zinc oxide works great, as an absorber and blocker of the suns UV rays. It's water resistant and does not absorb into the skin. So it will sit on your skin and stay there until you wash it off with a towel and soap. This is great for people Surfing or spending allot of tim directly in the water, were most sunscreens will wash off.
Zinc oxide is pure white, under the UV spectrum it is black. This means that it blocks all UV light. But as a sunscreen it actually is an absorber and transmuter of the suns UV rays. Through band-gap absorption it absorbs UV rays and turns them into infrared or heat. This is easliy cooled off when in the water.
When combined with Organic ingredietns such as beeswax and oils and color with food grade ingredietns so give it a skin tone look. You stay safe from the sun and also the toxic endocrine disrupting ingredients that most sunscreen use. Its the best of both world.