Does Sunscreen Expire? – Important Information on Skin Protection
YES, sunscreen does expire.
Sunscreens are designed to remain stable and at original strength for up to three years. This means that you can use leftover sunscreen from one year to the next.
Some sunscreens include an expiration date, or an indication of when the sunscreen is no longer effective. Discard sunscreen that’s past the expiration date, is more than three years old or has been exposed to high temperatures.
For optimal sun protection as well as texture, stability, and sterility, use the sunscreen prior to the date listed. If you can’t find a date on a new tube or bottle, write the month and year you purchased it in permanent marker on the tube.
Keep in mind, however, that if you use sunscreen generously and frequently, a bottle of sunscreen shouldn’t last from one year to the next. Generally, a liberal application is 1 ounce (30 milliliters) — the amount in a shot glass — to cover all exposed parts of the body. If you have a 4-ounce (118-milliliter) bottle, you’ll use about one-fourth of it during one application.
Sunscreen and Expiration
To maximize protection, use a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 15. The American Academy of Dermatology recommends using a broad-spectrum sunscreen with an SPF of 30 or more. Apply sunscreen generously 20 to 30 minutes before going outdoors and reapply about every two hours — or more often if you’re swimming or sweating. Be sure to rub the sunscreen in well.
For Coppertone products, the first character of the lot code represents the year of manufacture (7=2007, etc). The second character is a bit more involved. It will tell you the month of manufacture using this code: A=Jan, B=Feb, C=Mar, D=Apr, E=May, but then G=June, H=July, J=Aug, K=Sept, M=Oct, N=Nov, and P=Dec.
Per Scherring-Plough (the mfr of Coppertone) their SPF sunscreens have a shelf life of 3 years from the date of manufacture.
For Banana Boat products, the first 2
digits of the code represent the year it was made (07=2007, etc.) and the next 3 digits represent the day of the year (32=Feb 1st, 365=Dec 31st, etc). They also state a shelf life of 3 years.
To test shelf life, manufacturers store a product at 40°C with 75 percent humidity; then at 40°C with 25 percent humidity; and then test it at 0, 1, 2, and 3 months. Stability for three months in these laboratory conditions is comparable to three years in normal ambient environments. So your sunscreen should be good for up to three years after purchase.
Of the 17 sunscreen ingredients approved in the U.S. 15 are organic, or chemical, sunscreens: They work by absorbing damaging ultraviolet radiation (UVR). These chemical sunscreens consist of innately unstable molecules, but in the past few years manufacturers have started adding stabilizers like octocrylene.
Zinc oxide and titanium dioxide are physical, inorganic sunscreens; they reflect and diffuse UVR. Both are photostable and do not change molecular structure when exposed to UVR. Physical sunscreens once had an opaque, paste-like consistency, but in the past two decades manufacturers have developed cosmetically elegant formulations using micronized (tiny) particles. Since micronized titanium dioxide and zinc oxide can clump together over time, often the particles are coated with dimethicone or silica to keep the ingredients stable and smooth. And in addition to active compounds, sunscreens usually contain preservatives, emulsifiers, fragrances, and other additives.
Sunscreens are tested in their actual containers, since plastics in the container may leach into the sunscreen and cause a chemical interaction. UVR changes the molecular structure of chemical sunscreens, so sunscreen containers should be opaque.
For best results, use your sunscreen before the stated expiration date, and store it in a cool place. Please do not use expired sunscreen because then you will be left with peeling skin, sun burns and a lot of aging skin!
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