Does sunscreen actually expire, and if so, how do I tell if my sunscreen is expired, even if the expiration date isn’t printed clearly or is rubbed off? What are the risks of using expired sunscreen compared to using no sunscreen at all? Also, does the type of sunscreen (chemical vs. mineral, lotion vs. spray) affect its shelf life or how quickly it degrades?

Answer

Yes, sunscreen does expire.

The expiration date printed on a sunscreen bottle indicates the length of time the product is expected to remain fully effective. The FDA requires all sunscreens to remain stable for at least three years. After this date, the ingredients may degrade, and the sunscreen may not provide the same level of protection against the sun’s harmful rays (UVA and UVB).

Reasons for Expiration:

• Chemical Degradation: The active ingredients in sunscreen, such as avobenzone, octinoxate, and zinc oxide, can break down over time, especially when exposed to heat or sunlight. This degradation reduces their ability to absorb or reflect UV radiation.
• Formula Separation: The formulation of the sunscreen itself can separate over time, leading to uneven distribution of the active ingredients. This means that some areas of your skin may not receive adequate protection.
• Contamination: Although less common, expired sunscreen can be more susceptible to bacterial or fungal contamination, especially if it has been opened and used.

Signs of Expired Sunscreen:

• Changes in Texture: The sunscreen may become lumpy, grainy, watery, or separated.
• Changes in Color: The color may darken or become discolored.
• Changes in Smell: The sunscreen may develop an unusual or unpleasant odor.

Using Expired Sunscreen:

While using expired sunscreen is generally not harmful in the sense of causing a skin reaction or infection, its effectiveness in protecting against sunburn and skin cancer is significantly reduced. It is always better to use a sunscreen within its expiration date to ensure optimal protection.

Proper Storage to Extend Shelf Life:

• Store in a Cool, Dry Place: Avoid storing sunscreen in direct sunlight or in hot environments like your car.
• Keep the Cap Tightly Closed: This helps prevent air and moisture from entering the container, which can accelerate degradation.

Recommendations:

• Check the Expiration Date: Always check the expiration date before using sunscreen.
• Discard Expired Sunscreen: If your sunscreen is past its expiration date or shows signs of degradation, discard it properly.
• Use Sunscreen Generously: Apply sunscreen liberally and reapply every two hours, or more often if swimming or sweating.
• Store Opened Sunscreen Appropriately: Even before the expiration date, store sunscreen as recommended to maintain its efficacy.