If you want to be a delicate girl/boy in winter, how can you live without hand cream?

Author: Ma Xiaoshu (Center for Excellence in Molecular Plant Sciences/Institute of Plant Physiology and Ecology, Chinese Academy of Sciences)

The article comes from the Science Academy official account (ID: kexuedayuan)

"Hey, Xiaoshu, Xiaoshu, can you lend me the hand cream you just bought?"

"Hey, Junior Sister, your hand cream smells so good. Where did you buy it?"

Since the beginning of winter in November, the laboratory has welcomed a new wave of hand cream exchanges. Whether it is the rose scent or the fresh and elegant scent, it is sought after by many (brothers) and sisters. For delicate girls and boys who love beauty, the beauty of hands is sometimes even more important than the face.

The need for “hand protection” has existed since ancient times

Since ancient times, human life has been inseparable from hard-working hands. However, if our hands are in contact with detergents, water, solvents for a long time or are exposed to the sun and dry and cold air for a long time, it will cause the skin of the hands to become rough or even cracked, and it is easy to cause symptoms such as peeling and dryness.

Therefore, people's hands, which they rely on for survival, are receiving more and more attention. In leisure time, hand care is particularly important.

Our ancestors invented many ways to protect their hands. For example, Li Shizhen's Compendium of Materia Medica records: "Pearls are salty, dry, cold and non-toxic. They can calm the heart and eyes...apply them to the hands and feet to remove skin irritation."

However, this recipe is very complicated and the raw materials are quite expensive. It is really time-consuming and costly. It is only suitable for wealthy families. For ordinary people, it is a bit of a fantasy.

Modern scientific development and technological progress have made convenient and cost-effective hand protection products accessible to ordinary people.

Hand cream has become a necessity in our lives, especially in the dry and cold winter. If you want to be an exquisite girl/boy, how can you live without it!

But do you really understand it? Today, I will share with you what ingredients are hand cream made of? What is the principle behind its skin care effect? ​​Some hand creams are very expensive, while others are very cheap. Why is there such a big price difference between them?

Why can hand cream “protect hands”?

As we all know, the main function of hand cream is to replenish the oil components needed by the hand skin in time, moisturize the skin to maintain skin moisture, relieve dryness symptoms, so as to achieve the effect of preventing skin cracking in autumn and winter.

Its principle is also extremely simple, which is to form a continuous protective oil film or polymer film on the skin to reduce the rate of water loss from the skin, forming a dynamic balance between oil and water moisturizing factors, thereby keeping the local skin in a well-moisturized state [1].

Currently, the emulsifiers for skin care products on the market are mainly composed of two systems: water-in-oil type O/W type [2] and oil-in-water type W/O type [1]. (Note: O stands for oil and W stands for water.)

Among them, the W/O system has many advantages over the O/W system: good antibacterial properties, good moisturizing properties, and the appearance of W/O emulsions or creams is also more beautiful. At the same time, the moisturizing degree after use, the brightness of the cream, and the waterproof and sweat-proof ability are also significantly better than the O/W type [1].

However, the W/O emulsification system also has some shortcomings: it requires a very high oil phase, making it difficult to make a refreshing formula; it needs to add wax, resulting in a poor skin feel; the skin feel of the system after application is more sticky and heavy than that of the water-in-oil type; the stability of the formula is greatly affected by temperature changes; and the difficulty of formula design and production process control is greater than that of the O/W system[2].

Therefore, most hand creams on the market use an O/W system with a high oil content. The emulsion properties in these systems have been thoroughly studied.

How to choose hand cream according to needs?

The common ingredients of hand creams for different purposes are also different. Exfoliating hand creams are suitable for skin that is rough due to labor. For example, people whose hands have a well-developed stratum corneum and whose palms are particularly prone to thick calluses or hangnails and dead skin should use hand creams containing fruit acid ingredients or strong exfoliating particles to make their hand skin smoother.

Common ingredients of this type of hand cream are: fruit acid, salicylic acid, polyethylene particles, aluminum oxide, and apricot kernel particles.

The repairing hand cream is suitable for hands with aging lines, such as those with hands full of lines due to aging.

The common ingredients of this type of hand cream are: yeast, royal jelly, nutmeg seed, hydrolyzed soy protein, amino acids, and peptides.

In order to let everyone better understand the components of hand cream, we have selected several common hand creams on the market and introduced their ingredient lists in detail.

Exfoliating hand cream, taking a certain brand of hand cream as an example, its main ingredients include:

1. Plant-based collagen C: a moisturizing ingredient containing carrot extract.

2. Avocado: moisturizing ingredient.

3. Glycerin: a natural moisturizing ingredient.

This type of hand cream has a super penetrating moisturizing effect, which can allow moisture to penetrate deep into the stratum corneum, giving the skin full nourishment and care, making the skin on the hands fully moisturized, full of elasticity and luster.

As for restorative hand cream, taking a certain brand of hand cream as an example, the main ingredients include:

1. Fruit oil: It is a rich moisturizer, easily absorbed, rich in unsaturated fatty acids, can enhance the skin's moisturizing ability, and can moisturize dry skin and damaged skin.

2. Glycerin: a natural moisturizer.

3. Silicone, Dimethicone, Dimethicone: It is non-volatile liquid silicon, a synthetic silicide. High-purity silicone is almost non-toxic. It can give products a smooth and silky feel and form a thin film on the skin. It is usually used to assist in makeup or conditioners to create texture. It has many applications and variations depending on the viscosity.

Why do prices of hand creams vary from brand to brand?

There is a very important quality evaluation standard for hand cream, which is generally speaking, moisturizing performance. The prices of hand creams from different brands vary greatly, but are these high-priced hand creams necessarily of good quality?

Recently, the Shanghai Consumer Protection Committee conducted such a test. They purchased 27 hand creams from large shopping malls, brand stores, supermarkets and online e-commerce platforms, covering many high-end brands, with prices ranging from 4.2 yuan to 790 yuan.

The testers tested the moisturizing effect immediately, for 2 hours, and for 4 hours under the conditions of an ambient temperature of 20-22°C and a relative humidity of 45%-55%, with the basic moisture content of the stratum corneum being 15-45%. Generally speaking, the greater the difference in the incremental value of the stratum corneum moisture content, the better the moisturizing effect of the sample.

However, the test results are surprising. Taking the 4-hour moisturizing effect as an example, the moisturizing effects of hand creams of various brands are significantly different. The highest of the 27 samples was 25.22, and the lowest was only 1.71. Among them, the values ​​of 4 samples were above 20, with excellent moisturizing effects; 10 samples were between 15 and 20; 9 samples were between 10 and 15; 2 samples were between 5 and 10; 2 samples were below 5, with average moisturizing effects. Surprisingly, the two samples with a 4-hour moisturizing effect of less than 5 are both foreign brands. Moreover, the unit weight price of some samples with similar moisturizing effects is quite different. Sometimes, you spend dozens of times more money, but the effect of the goods you buy is not "flying to the sky"! Compared with foreign brands, some domestic brands are not inferior in moisturizing effects, but the unit price is relatively affordable.

Ladies who spend money, this hurts a lot!

We think that the more expensive the hand cream is, the better it is. Instead, you should choose it based on your personal needs. Our domestic brands are also a good choice.

I wish you all have a pair of white and smooth hands!

References:

[1] Liu Gangyong. Study on the stability of water-in-oil cosmetics[J]. Surfactant Detergent Industry, 2002, 32(6): 57-62.

[2] Zhang Junmin. Luo Jianhui. Study on the performance of W/O emulsion in cosmetics [J]. Guangdong Chemical Industry, 2009, 4 (36): 51-57.

[3] Li Na. Sunscreen cosmetics and their future development [J]. Tianjin Chemical Industry, 2004, 7(6): 23.