Both zinc oxide and titanium dioxide sunscreens are specifically designed to protect the skin from UV radiation damage. Although these metallic media block UVA and UVB radiation, they are different from chemical sunscreens that are immersed in the skin and absorb light. Although titanium has good stability and reflectivity, suitable zinc oxide particles provide the lowest opacity and better safety protection at the same concentration. Sunscreen manufacturers often mix these two ingredients in the same product and possibly add chemical factors.
Although also known as sunscreen, products made with titanium dioxide or zinc oxide work by creating a physical barrier between the skin and sunlight. Like most chemical sunscreens, they block UV-B radiation that can cause sunburn. But unlike many chemical products, they also block UV-A radiation, a long-wave radiation that damages the skin for a long time.
Early zinc and titanium sunscreen formulations used relatively large particles, so the resulting white opaque product affected aesthetics. Modern zinc oxide and titanium dioxide sunscreens use 280-380 nm particles, which results in a more transparent effect. In general, zinc oxide is not as transparent as titanium dioxide in the same amount. It is for this reason that zinc oxide is also used to produce clear white lacquer.
Both products bring benefits to users, but improper use can also cause some trouble. Zinc is more resistant to sunlight than titanium dioxide, so a small amount of application provides broad spectrum protection. Zinc oxide particles are not absorbed by the skin and do not cause allergies. Titanium dioxide is safe when coated with alumina or silica, but no cover particles can cause carcinogenic factors when exposed to sunlight. Both ingredients are suitable for sensitive skin or people who are allergic to chemical sunscreens.
Many companies produce sunscreens that mix zinc oxide and titanium dioxide, which can enjoy the maximum sun protection of zinc and the high reflection of titanium at low prices. Titanium dioxide is also very resistant to discoloration after exposure to UV radiation and is therefore very stable. Most physical sunscreens contain these two metal compounds and may contain other chemical components such as avobenzone.