Skin lipidomics decipher the horrible truth of acne
Nov 26,2021 | HISEEK PRETTY
Traditionally, the understanding of cosmetic oils is mainly from the perspective of skin feel, whether it is greasy, how stretched, and even the moisturizing comparison of different oils.
We can get more enlightenment from skin lipids. Skin lipids are also a kind of oil. Now we can find shadows in skin lipids with many classic raw materials, such as ceramide, squalene, and vitamin E.
Always talk about skin lipids. What are skin lipids?
Skin lipids are made up of sebocytes, keratinocytes, and micro-ecological components produced by the skin. The fatty acids in sebum can kill bacteria and can resist molds and viruses, which can be called the natural barrier of the skin. Since sebum contains fat-soluble metabolic waste products that the body does not need, sebum has a certain excretion effect. Sebum has a protective and moisturizing effect on the skin, but too much sebum can cause seborrheic dermatitis, such as acne, acne, acne, dandruff, etc.
It has three main functions:
①Physical and chemical functions. In the classic "brick-mortar" model, skin lipids refer to "mortar", which cooperates with "bricks" (stratum corneum and protein) as a physical barrier against the outside world.
②Biochemical function. They function as signals in a complex signal network at the epidermal level. For example, ceramide is a signal that regulates epidermal function. It can activate a variety of downstream signals, including cell proliferation, differentiation, and epidermal cell apoptosis.
③Micro-ecological function. The lipids derived from sebocytes and keratinocytes change the composition of the microbial skin flora, which is metabolized by the microbes to produce lipids, thereby initiating signal transduction.
There are thousands of lipids on the surface of human skin. How do we study them? It can be studied by the method of omics, that is, skin lipidomics. I won't talk about it in detail.
Today we look at the role of oil under different skin problems from the perspective of skin lipids.
Acne caused by cosmetics is a commonplace problem. The classic blacklists for acne are derived from rabbit ear experiments, including cocoa butter, isopropyl palmitate, lanolin, and myristyl lactate. Some people say that the results from rabbits cannot be completely copied to the results of humans, or that there are so many cosmetic ingredients, only testing these ingredients may not meet everyone's needs, and so on.
This time I will explain it to you from the perspective of skin lipids. Skin lipidomics studies have shown that compared with healthy people, the total amount of ceramide in people with acne rises, but the average chain length of ceramide decreases. Therefore, in the future, everyone should not be excited about ceramide. Ceramide There are good and bad points.
In addition, the unsaturated fatty acids in the skin of people with acne have increased significantly. Of course, there are a bunch of cell laboratories behind them to verify these mechanisms, so I won't go into details here. Therefore, in addition to the previous acne-causing ingredients derived from rabbit ears, we need to pay attention to the results obtained by skin lipidomics. We also need to be wary of some vegetable oils with more unsaturated fatty acids. For example, the dosage of isopropyl palmitate is 1 to 5%. Acne index: 3～4. In terms of texture and molecular weight, it can't be said to be "heavy" oil, and its acne-causing effect is not low. ○ The dosage of lanolin is less than 1%, and the acne index is 3. Another counterexample is that is naturally safe. ○ The dosage of isopropyl isostearate is 1 to 5%, and the acne index is 4 to 5. These data are not necessarily comprehensive, but they are all obtained through reliable experiments, and I hope it will be helpful to everyone in choosing products. It is difficult to generalize the performance of acne-causing ingredients in different types of products, and even the methods used will have an impact on the final result.
So, what is the simple and crude conclusion? For acne-prone skin, if you are not sure about the difference in vegetable oils, then don't use skincare products that contain more vegetable oils.
Many people know that sensitive skin is caused by a damaged skin barrier and should be repaired with more oil. But few people know that different oils have different effects on sensitive skin.
According to recent studies of lipidomics, glucosylceramide is more worthy of attention than ceramide, and glucosylceramide in normal people is 6 times that of sensitive skin. Glucosylceramide is the precursor of ceramide. More importantly, it can be used as a signal to inhibit cell apoptosis. The occurrence of sensitive skin at the microscopic level is also considered to be related to cell apoptosis.
In addition, the length of the fatty acid carbon chain is also very important for the repair of sensitive skin. The longer the fatty acid chain, the tighter the lipid accumulation and the better the skin barrier. For example, triterpenes, tocopherols, these ingredients also have certain anti-inflammatory and antioxidant properties. For sensitive skin, beware of oils with short fatty acid chains, such as lauric acid, palmitic acid, and coconut oil. Finally, sensitive skin also lacks phytosphingosine. At this time, phytosphingosine is no longer just a brick wall, it is also the skin's own antibacterial and anti-inflammatory agent.
The application of skin lipidomics is more than that. For example, the difference between male and female facial oils is not only the problem of large amounts and a small amount but also different types of lipids. Female skin is generally softer and smoother than male skin and contains a lot of phospholipids. Related to phospholipids, phospholipids will increase the fluidity of skin lipids.
In general, skin lipidomics, as a new research method, reveals to us that in addition to the difference in skin feel, the oils in cosmetics also have different meanings in skin physiology. But this is just the beginning, and a lot of in vitro and human experiments are needed to test.