I really want to ask: Can you use expired cosmetics? Will it "smudge" your face?

Can expired cosmetics be used? I believe many people have had this question. It is a pity to throw it away, but you are afraid that it will "smudge your face" if you use it. So, can you use it? What will happen if you use it? Today, let's talk about it.

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First of all, the conclusion: expired cosmetics are not completely unusable, but there are multiple risks, so it is recommended not to use them as much as possible.

What we mean by “effective date”

What does it mean?

Food, medicine, skin care products or cosmetics all have expiration dates, which refer to the deadline for which the corresponding product can maintain its full effectiveness and safety under specified storage conditions.

Take medicines or cosmetics as an example. After expiration, it does not mean that their effects will disappear immediately or necessarily become harmful. Instead, it means that the effectiveness of the product may begin to decline and the risk after use begins to increase.

The shelf life of cosmetics is often determined through stability tests, which simulate the chemical stability of cosmetics during storage. Similarly, for pharmaceuticals, testing includes accelerated stability tests, which are short-term tests under high temperature and high humidity conditions to predict long-term stability.

In addition to temperature and humidity, factors such as packaging, dosage form, usage conditions, and storage conditions will also have a certain impact.

It can be said that the expiration date is a very important reference indicator for cosmetics, and the safest way is to use them before they expire.

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Expired cosmetics

There will be 3 types of changes

What happens when cosmetics expire?

From a macro perspective, there may be many changes, but when it comes to a specific product, it is difficult to predict accurately.

1

Causes microbial contamination

A more common change is microbial contamination. The preservative system of expired cosmetics may fail, which is particularly prone to the proliferation of bacteria and fungi. For example, a study showed that the total number of bacteria in expired mascara samples reached 2.54×10⁴ CFU/mL and the total number of fungi was 2.55×10⁴ CFU/mL, which is much higher than the safety standard. Although these microorganisms are not always harmful, pathogenic bacteria such as Staphylococcus aureus and Pseudomonas aeruginosa occasionally appear.

2

Changes in chemical composition

The chemical composition of expired cosmetics may also change, especially the active ingredients may degrade over time and lose their original efficacy. For example, the chemical composition of sunscreen may not provide sufficient UV protection after expiration, and the sun protection effect will be discounted.

Even some ingredients (such as oils and fats) may oxidize or become rancid, produce odor or discoloration, and then generate harmful chemicals. People with life experience may know that lard will also become rancid if it is left for a long time in hot weather. The principle is the same.

3

Changes in texture and appearance

Subjectively, we may also find some changes, such as changes in texture and appearance, such as lotions or creams may separate, thicken or thin, powdered cosmetics may clump or lose fineness; color and smell may also change, darkening, yellowing or producing odor. These changes not only affect the user experience, but may also be signs of microbial contamination.

To sum it up simply, expired cosmetics may become unsafe, ineffective, and difficult to use.

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Using expired cosmetics

What are the dangers?

Brazilian scientists previously conducted a survey and found that 97.9% of female students have used or are using expired cosmetics (especially mascara), and even 70.5% of students have expired cosmetics on hand.

After statistics, they also found that 2.2% to 18.2% of people will have some suspected adverse reactions after using expired mascara, such as tearing (most common), redness, itching, irritation and allergies.

Another study found that a variety of bacteria and fungi were detected in expired lipsticks, including Staphylococcus aureus, Escherichia coli and Pseudomonas. These microorganisms may enter the human body through the oral mucosa and cause cheilitis, oral ulcers and even more serious infections.

More than that, to sum up, expired cosmetics have the following potential dangers:

1) Certain ingredients in cosmetics may produce new chemicals after degradation, which may be more sensitizing to the skin, causing skin irritation and allergies, manifested as skin redness, swelling, itching, stinging, etc.

2) If you are unlucky, there may be drug-resistant bacteria, such as some E. coli and some Pseudomonas. This means that if you really get an infection after using expired cosmetics, conventional antibiotic treatment may not be effective, and the difficulty of treatment and the risk of infection will be greater.

It can be seen from this that expired cosmetics are a bit like a blind box, and may cause unpredictable side effects.

How to use cosmetics well?

Here are 3 ideas

1

Pay attention to product expiration dates and storage conditions

Develop good habits when buying cosmetics, choose regular channels to buy reliable brand cosmetics, and check the production date and shelf life. Try not to buy products that are near or expired, especially eye cosmetics, because they have a high risk of microbial contamination after expiration.

Regarding the storage of cosmetics, it is generally recommended to store them in a dry, cool place, avoiding high temperature and humidity, in order to extend their shelf life and reduce the risk of microbial growth.

2

Develop good personal hygiene habits

On the one hand, you should ensure that your hands are clean before using cosmetics to avoid bringing bacteria on your hands into the product.

On the other hand, try not to share cosmetics with others, especially eye products, to reduce the risk of cross-infection. Studies have confirmed that the level of microbial contamination in cosmetics shared by multiple people is significantly higher than that in single-use and unexpired cosmetics.

In addition, makeup tools (such as sponges and brushes) also need to be cleaned and disinfected regularly, or replaced regularly.

3

Observe changes in cosmetics

During use, you should also pay attention to changes in cosmetics. If the color, smell or texture of cosmetics becomes different from before, even if it is not expired, you should try to avoid using it, as this may be a sign of microbial contamination.

If you can follow these tips, I believe you can greatly reduce the health risks caused by cosmetics.

References

[1] Giacomel CB, Dartora G, Dienfethaeler HS, Haas SE. Investigation on the use of expired make-up and microbiological contamination of mascaras. Int J Cosmet Sci. 2013; 35(4): 375-380.

[2] Microbial analysis of expired and 'in used' cream, liquid and matte lipsticks. http://www.jetir.org/papers/JETIR2207371.pdf

[3] Vella V, West LM. Analysis of disposed unused medications at a village community pharmacy. Pharmacy (Basel). 2019; 7(2): 45.

[4] Cosmetics and health: usage, perceptions and awareness. https://www.banglajol.info/index.php/BJMS/article/view/13330

[5] Skowron K, Jakubicz A, Budzyńska A, et al. Microbiological purity assessment of cosmetics used by one and several persons and cosmetics after their expiry date. Rocz Panstw Zakl Hig. 2017; 68(2): 191-197.

Planning and production

Author: Tang Jiaoqing, MD, attending physician of dermatology

Review | Feng Jun, deputy chief physician of the Dermatology Department of Sinopharm Tongmei General Hospital

Planning丨Zhong Yanping

Editor: Zhong Yanping

Proofread by Xu Lailinlin