12/6/2023 0 Comments No ad sunscreen expiration dates![]() ![]() ![]() Zinc oxide sunscreens are also photostable - which means their active ingredient (zinc oxide) does not deteriorate in sunshine. They work immediately and do not seep into the skin like petrochemical products. These sit on top of the skin where they absorb UV rays, convert them into infrared heat energy, then dispose of the heat away from the skin. Physical sunscreens utilize minerals zinc oxide or titanium dioxide as active ingredients. You should never use a chemical sunscreen after the expiration date has passed. Unable to convert UV rays into harmless energy as well as mineral sunscreens, active petrochemical ingredients are actually photo-degraded by both UV energy and each other - breaking chemical bonds, disabling UV absorption capacity, and creating reactive free radicals in the body.Īlso, additives in chemical sunscreen, such as emulsifiers, which help water and oil mix together, often break down sooner than other ingredients. ![]() Such derived substances are known collectively as petrochemicals.Īt best, petrochemical sunscreens exchange UV damage for toxic chemical damage. The main difference between the two types of sunscreens is that physical sunscreen sits on top of the skin to reflect and absorb UVA and UVB rays, whereas chemical sunscreens absorb into skin and creep into our bloodstreams.Ĭhemical sunscreens apply smoothly, without leaving a thick film, using active ingredients such as oxybenzone, octinoxate, homosalate, octocrylene and avobenzone, which are created by extracting and processing various chemicals from crude oil. Again, zinc oxide sunscreen does not expire and does not lose its ability to protect skin from UV rays. True physical sunscreens contain either zinc oxide or titanium dioxide as their only active ingredient. The Food and Drug Administration (FDA) requires all sunscreens remain at full strength for 3 years from purchase date, but that ruling was created because of petrochemical sunscreens, not physical sunscreens that use zinc oxide. It will always be effective against UVA and UVB rays, no matter how long the product that contains it sits on a shelf or in a hot garage. Zinc oxide sunscreen does not expire, because it contains the mineral compound zinc oxide, a solid inorganic substance of natural occurrence - in other words, neither time nor sunshine changes its molecular structure. But you only have last year’s sunscreen in your bag and you’re wondering, does zinc oxide sunscreen expire? When headed outside for a full day in the sun, it's even more important to make sure you apply sunscreen. Pro tip: If your new sunscreen doesn’t have an expiration date, write the date you purchased it on the bottle as a reminder that it’s only good for 3 years.Wearing facial sunscreen daily is the best way to protect human skin from sun damage.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |