The fat man said with a smile: "There are many dishes in Zhejiang cuisine that use bird's nest shark fin as the main ingredient, but when I am at home, except for the occasional thought of eating a fresh one, I usually don't think about eating these things at all." I don't lack meat to eat, and to be honest, pig's trotters are more nutritious than bird's nest shark fin. Even sharks themselves have to get cancer, and I really don't believe that this shark fin has any shark chondroitin that can really fight cancer. Eating pig's trotters can also have a certain amount of fat, and there are a lot of other proteins or something, what is left of these things except collagen?"

"Just like the third child said, since the skin can't absorb macromolecular substances, since you want to achieve the purpose of nutrition, you should boil this seaweed seed and eat it, which will have a better effect on you, at least you eat it, and it can be more or less turned into some protein in the body. ”

Liu Liping looked white and fat: "You look fat and fat, what kind of fat do you need to supplement?" Finally, you're back, then let me ask you that vitamins can always be absorbed, right? You just said that water-soluble substances can't enter cells, what about fat-soluble ones? ”

Xu Yi smiled and nodded, reached out and took the body lotion that Liu Liping placed on the coffee table, looked at the instructions on it, and said: "As an important line of defense to maintain the stability of the internal environment, the skin has to resist the invasion of foreign substances after all, so its compactness and defense function are the most important. ”

"You see, in addition to water, glycerin, petroleum jelly and butylene glycol and high-grade alcohols, these things are supposed to be the basic materials for the formation of the lotion, and the remaining sodium hydroxide, palmitic acid pentapeptide and vitamins should be to adjust the pH or the so-called things that want to nourish the skin, plus paraben as a preservative, if I remember correctly. Paraben has the best inhibitory effect on bacteria under slightly alkaline conditions, and the effect of sodium hydroxide can also be seen here. It is equivalent to auxiliary antiseptic. ”

Liu Liping listened, her eyes lit up. He said, "This thing is alkaline, so it doesn't fit my skin perfectly, but so much sodium hydroxide is fine, right?"

Xu Yi smiled and shook his head, "Silly girl, don't be sentimental, this little hydroxide can't change anything, don't talk about this, even if you drink vinegar or caustic soda solution without causing harm to your body, it can't change the pH of any organ except the digestive tract." ”

The fat man said out of tune next to him: "Even if you see the fourth child holding two beautiful women, it won't make you acidic." ”

Yan Peimin saw that Liu Liping's face changed. Hurriedly jumped out to show his loyalty, stretched out his hand to hook Liu Liping's waist, and said: "Fuck off, you just hugged the two beauties, it's enough for me to have Liping in my family." ”

Liu Liping slapped Yan Peimin's salty pig hand down, rolled his eyes and said: "Go to the dead side, who belongs to your family, is there any evidence?"

"What evidence do you want, shall we go and get the certificate now?"

Liu Liping pouted. said: "You are so beautiful, how can you have time to go home and do it, let's talk about it when you graduate." ”

Xu Yi calculated in his heart, raised his hand and said: "A sodium hydroxide solution with a pH of eight is equivalent to the concentration of hydroxide, which is approximately equal to ten to the minus sixth power of moles per liter. A liter of water dissolves forty grams of sodium hydroxide is one mole per liter, and if only sodium hydroxide is added to pure water, this ten is minus six power. Just add 0.04 grams to a ton of water, so don't think about how much sodium hydroxide is in it. Even with this concentration of potassium cyanide, you won't be poisoned if you eat this bottle. So you don't have to worry about this, it won't have any effect on your skin. Similar is the preservatives in this cosmetics, there are not many of them, it doesn't hurt to eat them, let alone rub them on the skin, if there are no preservatives in this thing, it is even more of a cheat's goods, after all, nothing can be used up at one time, the nutrients are so high, if there are no preservatives, this thing has long been broken, so this additive-free is pure and natural, how can it not be taken out and sold, it is just a gimmick, even if the final product is not added, as long as it is added in the front raw materials, this is not added in disguise？”

"There is nothing to say about the emulsion, it is nothing more than the suspension formed by the emulsification of water on the surface of small grease particles, let's talk about these things added to it. ”

"The palmitic acid pentapeptide should literally be an oligopeptide containing five amino acid molecules prepared with palmitic acid. However, we generally call it pentapeptide, or pentapeptide to maintain a sense of mystery, in fact, to put it bluntly, such a short peptide chain generally does not have too strong antigenicity. Of course, this thing should be able to be absorbed by the cells, and if it is really put into the fibroblast culture medium in the real yàn room, it is possible to promote the speed of collagen synthesis by the cells. However, this is applied to the surface of the skin, and it also has to pass through the stratum corneum to the basal layer, which is dead and alive, dozens of layers of cells to reach the dermis, so this can only be a beautiful function, but in fact it is useless. ”

"After all, even if the small intestine has such an area and is in a moist state, it still has to rely on various digestive enzymes to break down various substances into small molecules before it can be absorbed into the body, and it can be said that this area is the basis for ensuring adequate nutrient intake. Clinically, there is a disease called short bowel syndrome because of small intestine surgery or intestinal fistula directing the small intestine and large intestine directly to guide the effective absorption area of the small intestine and large intestine, and the nutrients absorbed by the human body are insufficient, which leads to malnutrition, water and electrolyte imbalance in patients, and even because of the excess of intestinal nutrients, the harmful bacteria multiply in large numbers, produce exotoxins, and then affect a series of symptoms of human health. In addition, the small intestine is full of ciliated cells, which can also effectively increase the surface area of intestinal cells, but the skin is flat epithelium, which is smaller and more tightly combined, and lacks enough digestive enzymes to help digestion. ”

"The difference in nutrient absorption between the digestive tract and the skin may be greater than the water permeability of a sieve and a piece of rainproof silk. It can be said that even these five peptides cannot reach the dermis and have any beneficial effect on the fibroblasts of the dermis. ”

"For an extreme example, you can imagine that even if the surface area of the Shar Pei's skin is as much as 200 square meters of the small intestine, if you soak it in various hydrolyzed nutrient solutions that can be completely absorbed by the intestines, it will still starve to death!"

"Isn't my mask hydrating?"

"Yes, this has a certain effect, but the effect is also very limited, even if you soak the skin with water to the point of whitishness, or because of the use of scrubs or fruit acids to completely remove the stratum corneum, it is useless to rely on these things to supplement nutrients to the dermis, the excessive epidermal structure between the basal layer and the stratum corneum will still intercept these substances outside, not to mention that you are still an emulsion, which will form an oil film on the surface of the skin. ”

"Again, there are vitamin C and tocopherol in this thing, but in fact, these two things are vitamin C and vitamin E. It just so happens that one is fat-soluble and the other is water-soluble, so let's talk about it together. Xu Yi pointed to the ingredient list and said: "First of all, vitamin C, this thing is a strong reducing agent, sodium salt or preservative, let's not consider the problem of its reaction with sodium hydroxide in this ingredient list, just consider this thing is vitamin C." You also know that vitamin C, which is used as a medicine, must be kept away from light and sealed, right?"

Liu Liping said: "Well, yes, otherwise it will be oxidized by oxygen." ”

"But you know that this thing is called ascorbic acid, as the name suggests, it is an acidic substance, and it is also a very unstable substance, which oxidizes faster under alkaline conditions than in neutral or even acidic solutions. It is even possible that the air entering the bottle will oxidize it every time you use it. Even if the remaining bit is applied to the surface of the body, the contact area with the air is larger, and the efficiency of oxidation is greatly increased due to the temperature and surface area, and it is completely lost before it penetrates into the skin. If it is possible to increase the concentration, but don't forget, vitamin C is an acidic substance, and increasing the concentration will only cause corrosion to the skin, so it is useless to add less, and harmful to add more, and it doesn't matter if you add this thing or not, right?"

Seeing Liu Liping nodding, Xu Yi continued: "Vitamin C is an indispensable and important substance for the human body, and the lack of vitamin C will lead to a series of problems such as scurvy, but this does not mean that the more vitamin C intake, the better. ”

Liu Liping looked up at Xu Yi and asked suspiciously: "Didn't you say that you should take a large dose of vitamin C when you have a cold?"

Xu Yi nodded: "That's the case, there are still many people who supplement a large amount of vitamin C to cancer patients, in fact, this is also a very shameful thing in Western medicine, in fact, the use of vitamin C in large doses is useless for these diseases, and there will even be potential risks!"

"Isn't it?"

Xu Yi said: "Just like the claim that vitamin C can prevent colds and anti-tumors is actually quite unreliable, they only act as a placebo in these two diseases at best. ”

Vitamin C originated in the 70s of the last century, when the two-time Nobel Prize-winning chemist Linus Pauling wrote a book called "Vitamin C and the Common Cold", in which he claimed that taking 1,000 milligrams of vitamin C a day could effectively prevent the common cold, and since then the concept of vitamin C can prevent colds has been deeply rooted in the hearts of the people. ”

However, he won the Nobel Prize once for the study of chemical bonds, and the Peace Prize for anti-nuclear on the other, and none of them were related to vitamin C. Or his greatest achievement in life is to devote himself to promoting the benefits of vitamin C, but not because of the discovery and promotion of the function of vitamin C. Speaking of this, Xu Yi asked Liu Liping with a smile: "Suppose Mo Yan sells a bestseller, you might buy it, but if he sells any cosmetics, will you buy it?"

Liu Liping shook her head and said, "Of course not, can he understand?"

Xu Yi smiled and nodded: "That's it, Linus Pauling is not a medical worker, at best he is a chemist, and he doesn't have much medical knowledge, what's the point of his recommendation?" (To be continued......)