Check how effective your sunscreen is. Expiration date of cosmetics: what to throw away, what to leave? Shelf life of open sunscreen

The next time you go to the beach, be sure to check if your sunscreen is still working. Of course, it does not spoil as quickly as milk and other products, but still it has its own expiration date.

This period depends on the conditions in which you store your cream, explains Georgios Imanidis, professor at the University of Applied Sciences of Northwestern Switzerland.

If the tanning cream has been stored in a dry and cool place (in the pantry, for example), then it can remain usable for five or even ten years. Meanwhile, most manufacturers officially limit the service life of their creams to three years, and then if the product is stored under optimal conditions.

However, people often take sunscreen to the beach, leave it in a hot car, or carry it around in backpacks. When a tanning cream is heated, its constituent elements begin to disintegrate faster - which means that the expiration date of the cream approaches faster.

What is sunscreen made of?

Sun cream contains inorganic compounds such as zinc oxide or titanium dioxide. They prevent sunburn by absorbing or reflecting UV rays that would otherwise penetrate the skin.

But, in addition to this, the composition of the tanning cream also includes ingredients that give it a pleasant aroma and a soft, delicate texture, thanks to which the cream is easy to apply. These ingredients include natural oils, aloe vera, emulsifiers (substances that help oils and water mix into a homogeneous mass).

How does sunscreen go bad?

Emulsifiers are destroyed first. Without this ingredient, water and oil separate from each other, causing the cream to become too runny, too grainy, or simply no longer applies to the skin as well as it used to. In this case, just shake the bottle well before use, experts advise.

Over time, other components of the cream begin to break down, as a result of which it loses some of its sunscreen properties. But still - it's still a tanning cream, although not as effective as before.

For example, a cream with a sun protection factor (SPF) of 55 can eventually become a cream with 40 or 30 SPF. The number 55, 40 and 30 in this case means how much time a person can spend in the sun and not burn out. If a person usually gets burned in 10 minutes, then with SPF 30 he can stay in the sun 30 times more or 300 minutes (5 hours).

How often and how much cream to apply to the skin

It should be noted that few people apply as much cream to their body as manufacturers advise. The gold standard is 2 milligrams per square centimeter.

But if you are using an expired (i.e. less effective) cream and you are not applying enough cream to your skin, then at least reapply it every 2-3 hours.

Which is better - cream or spray

Also, keep in mind that sprays are less effective than creams:

“We found that the sprays did not last as long as other sun protection products,” says Prof. Imanidis. – If your cream is thick enough, you can apply it two to three times a day. And the spray will have to be used every hour.

Summer is in full swing, and if up to this point you have neglected sun protection, it's time to change that. We debunk the most popular myths.

In summer, sunscreen is indispensable - but it is often used incorrectly. Here are five myths associated with this remedy.

1. Sunscreen is not needed on cloudy days.

Many have found themselves in a similar situation: it is cloudy outside, you go out for a walk without protection from the sun, and in the evening you find that you have burned out. It is generally accepted that the cream can not be applied if the sky is covered with clouds - after all, they already protect the skin from the sun's rays. However, it is not. Clouds, of course, block some of the ultraviolet, but 80% of the radiation still reaches the Earth's surface. What's more, clouds can reflect ultraviolet rays, making the sun's negative effects even worse.

2. The most important thing is the SPF factor

All advice on buying a suitable product begins with what level of SPF you need to take (“of course, from 15 and above”) - as if these three letters decide everything. SPF (“sun protection factor” - sun protection factor) can be compared with distance marks in the pool: who is able to swim how much. With a cream with SPF 15, you can be outside 15 times longer than without sun protection, with SPF 30 - 30 times longer. That is, SPF does not indicate how much (as a percentage) it protects your skin from ultraviolet radiation. Although creams with SPF 15 block 93% of UV rays, and SPF 30 - about 97%.

There is also no specific data on the effectiveness of creams with different SPF factors. When testing, experts apply 2 mg of the product per 1 cm² of skin and already then determine the factor. The buyer usually uses 25-50% less than this volume. Moreover, the chemical composition of creams varies. The U.S. Food and Drug Administration identifies 17 types of molecules that reflect UV radiation. different lengths waves: from 200 to 400 nm on the electromagnetic spectrum. The remaining components of the cream are responsible for moisture resistance or stability. chemical composition, which also affects how long the UV protection lasts.

In Japan, Australia and Europe, authorities have already taken action to limit the level of SPF in sunscreens due to the fact that such products create in the consumer false sensation security. So, on the shelves of stores in these countries you will not find a cream with SPF above 50.

3. People with swarthy or dark skin do not need sun protection.

Everyone has different skin and some burn faster than others. It's all about the level of melanin - the skin pigment that absorbs UV radiation. However, you should not hope that melanin will protect you from the sun, and you do not need any cream: if the level of protection of melanin is calculated in SPF, we will get SPF 1.5-2. In addition, melanin is not as effective in dealing with the most dangerous UV rays - ultraviolet A, which penetrates deeper into the skin.

4. Why buy a new tube if you haven't run out of the old one yet?

Many believe that best before date on a tube of cream - this is just a trick of the manufacturer so that the product does not stay on the shelves. According to one survey, a third of buyers do not look at all best before date sunscreen. And you should pay attention to it: the components of the cream break down over time and lose their effectiveness.

Not only will the old cream not protect your skin - it can do harm. For example, the American cosmetics manufacturer Banana Boat was forced to recall all products manufactured between January 2010 and September 2012. It was found that these creams could "under certain conditions ... ignite on the skin" - for example, if a person applied the product and, without letting it dry, went to grill kebabs and brought his hand close to the fire.

By the way, if you always apply a sufficient amount of cream to the skin, by the end of the summer there will be nothing left of it, and the problem will disappear by itself.

5. Sunscreens are toxic.

Newspapers are full of headlines like "Sunscreen is bad for your skin" or "Sunscreen is a danger to your skin?". These concerns are due to recent studies in which the individual components of the creams were tested for side effects and possible negative consequences for health. The link between photoaging and skin cancer is well known; and here are the possible side effects from the use of sunscreens remain at the level of conjecture.

For example, in the United States, sunscreens are subject to scrutiny: since the late 1970s, these products have been allowed to be sold without a prescription, and now their quality is monitored more closely than that of any other cosmetic product that comes into contact with the skin.

Some newspapers even complain that Europeans have much more chemical ingredients in creams than America. The revision of the list of allowed elements has been dragging on since 2002, as a result of which US President Barack Obama even signed the Sunscreen Innovation Act in November 2014.

For all those who shy away from the word "chemistry" and don't even want to hear about using sunscreen, consider this: there are elements in plant spores that naturally block UV rays. The pigmented secretion that is secreted through the skin of the hippopotamus protects the animal from sunburn. Why don't people learn from nature and take an example from it?

As you know, sunscreen should protect against two types of harmful rays: UVA and UVB.

UVB results in sunburn, sunburn, and generally cause immediate and visible damage to the epidermis (top layer of the skin). UVA rays have the ability to penetrate deep into the skin, affect the dermis and show their effect for a longer period. This means that skin damage after UVA exposure is not immediately visible, appears much later, but is the main cause of photoaging.

The SPF filter protects against UVB rays, while the IPD or PPD filters protect against UVA.

With that in mind, we're here to help you test your sunscreen. To do this, it is enough to answer the seven most important questions.

1. Does your product offer broad spectrum protection?

How can you tell if your sunscreen is protecting against two types of rays: UVA and UVB? The phrase “cream with SPF” is not everything. You should make sure that the composition contains ingredients that are resistant to photoexposure. Look for the following names on the ingredient list: Zinc Oxide, Tinosorb S + Tinosorb M, XL + Mexoryl Mexoryl SX. New generation products also offer such a filter as Mexoplex Helioplex - if it is, then the protection of the cream is exhaustive.

This is important to know if you expect to be exposed to the sun for a long time. For such situations, you should buy a sunscreen with an SPF of at least 50, and containing one of the active ingredients listed above. You can also recommend sunscreen labeled "for outdoor sports", as well as waterproof cream (it tends to last longer).

3. Does your product protect against UVA rays?

Even if you avoid the sun all day, your skin is still exposed to insidious UVA rays. Damage from them does not appear immediately.

Therefore, it is worth checking your skin regularly for the appearance of new spots and mini-burns. As a rule, the harmful effects of UVA appear in a day. If you see that, despite the use of the cream, new redness appears on the skin (and this happens a day after exposure to the air), most likely you need to go to the store for a new cream, yours does not cope with harmful UVA rays.

4. Has sunscreen expired?

Most sunscreens have a decent shelf life of up to 3 years! However, this means that the product does not change its properties until the package is opened. If you have already started using a cream (for example, last summer or last season), then such a cream is only effective for a year after it was printed.

5. Do you store sunscreen properly?

You are doing the right thing if you take sunscreen with you when you leave the house for nature, the beach, and the open sun. After all, the cream layer needs to be constantly updated.

But trouble happens when a tube of cream remains under the open rays of the sun for a long time: on the beach, in the car. In this case, the cream can change the action of active ingredients that are damaged due to heat exposure. Therefore, make sure that the cream is always inside the cosmetic bag and, if possible, lies in the shade.

6. Which SPF number should I choose?

Choose preparations with the designation of SPF filters in accordance with accepted standards. They provide four degrees of solar protection:

- Very high degree of protection - factor 50+. Such funds are needed in the tropics and equatorial countries.

- high degree- 50, 30. These products will be needed on vacation by the water, in the mountains, at sea.

— Average degree- factors 25, 20, 15. If you spend the summer in the city, as well as in the middle forest, then medium protection is enough.

- Low- factors 10, 8, 6. Products with this indicator are intended for those who spend the whole day indoors. Products with a low and medium degree of protection can be switched after 5 days of constant use of products with a high degree of protection.

After 35 years, the skin is less protected from the sun, so protect it with preparations with a high and very high degree. After bathing, the SPF protection in waterproof preparations is reduced by 50%. SPF 50+ turns into SPF 25 and 30 turns into 15.

7. What should be the PPD number?

The degree of the PPD (or IPD) filter that protects against UVA rays should be 1/3 of the SPF protection.

Situation: You've just picked the perfect spot on the beach, unpacked your gear, and settled into a comfortable position to soak up the sun for as long as you want. Haven't forgotten anything? That's right, we are again about which, even despite how often and how much they talk about it in Lately, "inhabitants of the resorts" do not pay due attention.

But what if the sunscreen you thoughtfully took with you has expired? And you found it too late to go to the store and buy something fresher. Does it make sense to use such a cream, or in this case, you can do without it at all? Let's try to figure it out.

Live Science reminds that the protection of SPF products is based on active ingredients that absorb or reflect ultraviolet radiation. Among the most popular such ingredients are zinc oxide and titanium dioxide. At the same time, almost all modern products are classified as "broad-spectrum products", that is, they provide protection from both the ubiquitous UVA and more powerful UVB rays.

Here's what everyone needs to know: Most, unless the brand says otherwise, can remain effective for up to three years after opening the jar, according to the Mayo Clinic. “However, storing the cream in a sunny or humid place can compromise the integrity of some of the ingredients, reducing its effectiveness before the expiration date,” says dermatologist Lauren Ploch.

“Any ingredient in a personal care product, including inactive ingredients such as emulsifiers and preservatives, can lose its properties over time. best qualities she continues. “This degradation is often accelerated by suboptimal storage conditions, so storing sunscreen in, say, a car can render it ineffective even before it expires.”

Yes, an expired sunscreen will indeed be less effective at blocking UV rays, reducing the likelihood sunburn and risks associated with . But thick creams, which tend to provide better coverage and sun protection than gels and sprays, can still create a shield between skin and the sun, even if they've passed their expiration date (and even if it wasn't yesterday).

“Old sunscreen is definitely better than no sunscreen, especially if the active ingredient is zinc oxide or titanium dioxide,” says Ploch.

However, the expert points out that Sun protective equipment they differ greatly in the composition of active and inactive ingredients, so it’s impossible to say for sure how effective your sunscreen will be without examination.

Well, the final advice from a dermatologist. “Of course, you can use an expired SPF if there is no other choice. But I still recommend asking for sunscreen from someone on the beach, or gathering your strength to walk to the nearest store to buy a new one, ”concludes Lauren Ploch.

By learning about the most important aspects of using sunscreen, you can protect yourself from skin cancer and early signs aging.

Using sunscreen only outside

It should be used 365 days a year, not just at the beach. The sun's rays can affect the skin even when you are sitting by the window on the bus. To get used to using the cream daily, it is enough to find a moisturizer with an SPF of at least 15. You need to apply it every day after taking a shower.

It is not at all a guarantee of prolonged exposure to the sun. A high rate gives people a false sense of security. This causes serious damage to the skin. The optimal remedy is a cream with SPF 30, which should be applied every two hours or more often if you decide to swim.

Not enough cream

Most people use only 25 to 50% of the amount of sunscreen required. With proper use of the product, it should hardly be enough for one season. As a rule, in hot weather it is necessary to replenish its stocks several times. If you use little cream, then even a high SPF will be ineffective.

Expired date

It is worth checking the expiration date of sunscreen in a timely manner. An expired remedy may not have the desired effect, because chemical substances in its composition ceased to be active. Also, do not store lotion in the glove compartment of the car. When the vehicle is in the sun and heats up, it can accelerate the destruction of the protective substances in the cream.

Not using the cream on all required areas

It is not enough to cover only the arms, legs and back. The scientists who conducted the research came to the conclusion that the ears, lips, front and back of the neck, and upper legs are no less rarely affected by skin cancer. Sunscreen should be applied to these areas of the skin, and lips should be selected hygienic lipstick with SPF. For the scalp, it is worth choosing special protective products (sprays, mousses).

Timely application

Do not put off applying cream until you arrive at the beach or pool. It is best to do this at home. Firstly, the cream will have the opportunity to be better absorbed into the skin, which means that it will fully exert its effect. Secondly, you will apply the product more thoroughly, because on the beach it is easier to get distracted and tempted to swim, forgetting about precautions.

Wrong sequence

Everyone is used to applying cream after putting on a swimsuit or swimming trunks. As a result, after a day at the beach, you can notice stripes of burnt skin in places where the line between exposed skin and straps passes. That is why it is necessary to apply cream before putting on a swimsuit.

You don't always use broad spectrum sunscreen

The SPF number on sunscreen bottles is a measure of how well a product protects the skin from UVB rays, not UVA. Look for a bottle labeled "broad spectrum", which indicates the formula will also protect against UVA rays.

Color of the skin

While it's true that darker skin has natural protection against sunburn and skin cancer, that alone isn't enough to prevent damage. Even people from dark skin you need to apply lotion with SPF 30 every two hours.

Summer clothes protect from the sun

This is not true at all. It is not uncommon for people to get melanoma even in places that were protected by clothing. Therefore, it is worth carefully choosing a summer wardrobe, giving preference to breathable fabrics, as well as protecting the skin with sunscreen.

The effect of the cream is reduced by exposure to water.

There is no such thing as waterproof sunscreen, and manufacturers are not allowed to put that kind of information on their labels. Instead, they may say that the product is water resistant for 40-80 minutes. So, its application should definitely be repeated after two hours.

The price of the cream is not a guarantee of its effectiveness.

Many people are sure, having paid a high price for any product, in its highest efficiency. This doesn't always turn out to be true. An expensive product may smell better and have a much more attractive packaging design, but a cheap product is not always inferior to it in terms of protection. When choosing, you should pay attention to the composition, study the label in detail. So, protecting the skin from ultraviolet radiation will be effective.