Sunscreen can indeed expire. There are two main types of sunscreen: chemical and mineral based. Chemical-based sunscreens are often based on Oxybenzone, Avobenzone, or Octinoxate. Mineral-based sunscreens are based on Zinc or Titanium oxide.
Chemical reactions with the emollients or preservatives degrade sunscreens blocking effectiveness over time. FDA mandates that a formula must be stable for at least three years.
Mineral-based sunscreens can degrade due to UV and heat. It is best to store sunscreen in cool and dry containers without exposure to sunlight.
Additional fun fact: you can have an allergic reaction to either the active ingredients in chemical sunscreens, or to the chemicals that those sunscreens morph into when they react to UV (photoallergic contact dermatitis).
I kept thinking my sunscreen had expired even though it was new. I'd put it on and be fine for hours indoors, and then once I was exposed to sunlight I'd get burns and blisters. Turns out I can't use chemical sunscreens anymore. Mineral sunscreens (zinc and titanium) are frequently a better option if you've got skin that reacts to random things.
g2g079 on May 29th, 2023 at 15:37 UTC »
This was more than just a lotion problem
TheGenbox on May 29th, 2023 at 16:37 UTC »
Sunscreen can indeed expire. There are two main types of sunscreen: chemical and mineral based. Chemical-based sunscreens are often based on Oxybenzone, Avobenzone, or Octinoxate. Mineral-based sunscreens are based on Zinc or Titanium oxide.
Chemical reactions with the emollients or preservatives degrade sunscreens blocking effectiveness over time. FDA mandates that a formula must be stable for at least three years.
Mineral-based sunscreens can degrade due to UV and heat. It is best to store sunscreen in cool and dry containers without exposure to sunlight.
groggygirl on May 29th, 2023 at 16:43 UTC »
Additional fun fact: you can have an allergic reaction to either the active ingredients in chemical sunscreens, or to the chemicals that those sunscreens morph into when they react to UV (photoallergic contact dermatitis).
I kept thinking my sunscreen had expired even though it was new. I'd put it on and be fine for hours indoors, and then once I was exposed to sunlight I'd get burns and blisters. Turns out I can't use chemical sunscreens anymore. Mineral sunscreens (zinc and titanium) are frequently a better option if you've got skin that reacts to random things.