What is zinc oxide?

Daniel Judd BSc MBiol


What is zinc oxide? 

Zinc oxide is a widely used mineral made up of the metal zinc and oxygen. Around 100,000 tons of zinc oxide are produced each year from pure zinc, natural ores or solutions of zinc salts. It’s been used in medicine for thousands of years and as a paint pigment for hundreds.

Zinc oxide is also added to fortified cereals since zinc is an essential mineral in the human diet. This is typically safe and beneficial although there have been cases of pork products containing dangerous dioxins due to contaminated zinc oxide being added to the pig feed.

It is important in skin care as it works a UV absorber in sunscreen. It is usually used in combination with titanium dioxide, another mineral with UV blocking abilities.


How does it work? 

Zinc oxide works as an active ingredient in sunscreen where it absorbs the UV rays before they can reach your skin cells. This works as the individual zinc atoms can soak up UV light and then spit it out again as harmless infrared light. It can also be used in materials that need UV protection, such as the lenses of sunglasses.

Sunscreens are incredibly important in skin care as they protect the skin from sunburn, wrinkles and skin cancer. The UV rays found in sunlight can penetrate the skin and once inside they create dangerous and reactive molecules called free radicals. These free radicals can cause serious damage to your cells’ DNA leading to mutations and cancer. Your body tries to prevent this with an inflammation response seen in sunburn but this inflammation also damages the collagen in your skin, leading to wrinkled and aged looking skin.



Side effects:

Zinc oxide containing sunscreen may trigger an allergic reaction.

When zinc oxide is applied to the skin, some of it can be absorbed into the body. As zinc is essential in your diet, low amounts are not toxic and you are unlikely to absorb enough from sunscreen to experience overdose symptoms. Overdose symptoms include cramps, vomiting and diarrhoea.

Interactions with other medicines: 

Topical zinc oxide is not thought to interact with other medicines.


Other names: 

Zinc white, calamine, philosopher’s wool, Chinese white, flowers of zinc, oxozinc, zincite, zinc monoxide