With the arrival of the heat and the return on the days on the beach or in the pool, many Portuguese opened the summer bags stored since the previous year. In the middle of towels, sunglasses and hats, it is common to find a sunscreen bottle used last summer and with product inside. The question is installed: does this protector remain effective? Can it be used safely or should it be replaced?
Extreme conditions tested in the laboratory
According to the organization of consumers and users (occupa), eight sunscreens, six with protection factor 30 and two with a 50+ factor, underwent a set of laboratory tests to simulate the real conditions to which they may have been subject during and after summer.
Products were initially stored at 4 ° C to simulate aircraft transportation. Almost two weeks to 40 ° C followed, reproducing the intense heat to which they are exposed in the beach context, with the bottle to be opened regularly. After this phase, the protectors were radiated with UVB light using a solar simulator, then returning at a temperature of 4 ° C. Finally, they were kept for 14 months at about 20 ° C, replicating the usual storage at home.
Visual aspect is not enough to ensure effectiveness
After 14 months, the occupation experts analyzed the physical changes of the products. Two protectors showed visible signs of degradation. One was dry and the other with the altered texture. The rest kept the smell, smell, and consistency unchanged.
However, the organization warns that the appearance of sunscreen may not reflect its real effectiveness. Even if it seems intact, there is a possibility that filters have lost protection capacity against ultraviolet rays.
Results divided into UV protection
Of the eight products analyzed, six maintained the effectiveness indicated on both UVB and UVA label. Two, however, revealed loss of effectiveness against UVB, the type of radiation that most contributes to the sunburn. According to the same source, the data show that some protectors remain effective even after 14 months, but not all.
Sun Protection Factor (SPF) and UVA protection are among the most important elements to be verified. Changing these capabilities may compromise skin safety during sun exposure.
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Opinion of a national expert
Professor Helena Margarida Ribeiro, from the Faculty of Pharmacy of the University of Lisbon, recalls that the use of sunscreen is essential in any prolonged sun exposure. According to the expert, a protection factor equal to or greater than or more, is essential to renew the application every two hours, or whenever there is contact with water or perspiration.
The same expert also reinforces the importance of respecting the period indicated by the PAO (Period afterning) symbol, usually represented by an open vial with the number of months that indicates durability after opening. If the product has exceeded this limit, its effectiveness is not guaranteed.
In addition, the teacher explains that heat, light and moisture accelerate the degradation of active ingredients present in the formulas, compromising the ability to protect the skin.
How to evaluate the state of sunscreen
The same source recommends that, before reuse a sunscreen from the previous year, be carefully observed the texture, color and smell of the product. If there are changes, the protector must be discarded. Even if the expiration date or bread is still within the limits, physical signs of change indicate possible loss of effectiveness.
Storage in a cool, dry place is crucial to maintaining product stability. Exposure to excessive heat, such as the one that often occurs when the bottle is left inside a car in the sun, is one of the main causes of filter degradation.
If after this assessment, doubts persist about the integrity of the product, the most prudent is not to use it. Sun exposure without adequate protection poses an added risk to skin health.
The complete report with the products analyzed and the respective results is available on the website. For those who want to know if it is worth keeping sunscreen for the following summer, this analysis provides concrete data that helps make a more informed decision.
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