" is no longer an unfamiliar term. From anti-allergic and repairing creams to moisturizing serums, what kind of magic does this ingredient, dubbed the "core of the skin's natural barrier," possess? Why has it become a "savior" for people with sensitive and dry skin? This article will scientifically break down the nature, function, and application of ceramides, helping you understand this "skin's own protective factor."
I. What are Ceramides? The "Natural Protective Bricks" in the Skin
Ceramides are not a single ingredient, but a group of lipid molecules naturally present in the stratum corneum of the skin, accounting for 40%-50% of the total lipids in the stratum corneum. They are the "core building materials" that make up the skin barrier.
If we compare the skin barrier to a "brick wall structure," then keratinocytes are the "bricks," and ceramides are the "cement" that binds the bricks together-it not only tightly connects the keratinocytes but also forms a continuous protective film on the skin surface, resisting external stimuli and locking in moisture.
Endogenous ceramides: Synthesized by the skin itself, relying on fatty acids, cholesterol, and other raw materials secreted by the sebaceous glands, and gradually produced during the maturation of keratinocytes. However, with age (decreasing by 1% every year after age 25), UV exposure, lack of sleep, and stress, the skin's own synthesis ability gradually declines.
Exogenous ceramides: Supplemented externally through skincare products, medical aesthetic procedures, etc. They are commonly found in plant extracts (such as wheat germ, rice bran), microbial fermentation, or chemical synthesis. Their molecular structure is highly similar to the body's own ceramides and can directly fill gaps in the skin barrier.
II. The 3 Core Functions of Ceramides: More Than Just Moisturizing, They are the Skin's "Guardian Angels"
1. Water Retention and Moisturizing: Preventing Water from "Sneaking Away"
The root cause of dry skin is often "barrier defects"-when ceramides are insufficient, the gaps between keratinocytes become larger, and water evaporates rapidly through these "gaps" (i.e., "transepidermal water loss," TEWL value increases). Ceramides act like a "sealant," filling in gaps and reducing moisture evaporation, while simultaneously forming a moisturizing film on the skin's surface, restoring hydration and elasticity to dry, flaky skin.
2. Barrier Repair: Defending Against External "Invasion"
A healthy skin barrier blocks external irritants such as dust, pollutants, and UV rays, and prevents bacterial invasion that can cause inflammation. When the barrier is damaged (e.g., due to excessive cleansing, frequent exfoliation, or the use of irritating skincare products), ceramides are lost in large quantities, and the skin becomes sensitive, red, and itchy, even developing redness and acne. Supplementing with ceramides at this time can accelerate stratum corneum repair, rebuild barrier function, restore the skin's "resistance," and reduce the occurrence of sensitive symptoms.
3. Anti-Aging and Stabilization: Delaying Skin "Aging"
As we age, the skin's ability to synthesize ceramides decreases, barrier function weakens, and moisture loss accelerates, leading to the gradual appearance of fine lines, wrinkles, and sagging. Long-term supplementation with ceramides not only maintains skin hydration but also enhances the barrier's ability to resist free radicals, reducing the damage caused by external stimuli to the skin's collagen fibers, thereby delaying the formation of dry lines and fine lines, and keeping the skin firm and youthful.
III. How to Choose Skincare Products Containing Ceramides? Look at These 3 Points to Avoid Pitfalls
Faced with the wide variety of "ceramide products" on the market, many people fall into the misconception that "the more ingredients, the better." In fact, when choosing a product, you should focus more on its "effectiveness," keeping these three key points in mind:
1. Look at the "type" of ceramides: Match your skin's needs.
Ceramides have several subtypes (such as Ceramide 1, 3, 6 II, etc.), and different subtypes have different functions:
Ceramide 3 (Ceramide NP): The closest to the ceramides synthesized by the human body, it is a core ingredient for repairing the skin barrier and locking in moisture, suitable for sensitive and dry skin for daily use;
Ceramide 1 (Ceramide EOP): Mainly acts on the surface of the skin, enhancing the barrier's resistance to external stimuli, suitable for skin with damaged barriers and prone to redness;
Ceramide 6 II (Ceramide AP): Can promote the maturation of stratum corneum cells and help maintain barrier stability, suitable for rough and dull skin.
It is recommended to prioritize products containing 2-3 types of ceramides, combined with cholesterol and fatty acids (these two ingredients, along with ceramides, are known as the "three major lipids of the stratum corneum"), for a more comprehensive repair effect.
2. Look at the concentration and formula: Avoid "conceptual addition."
Many products add ceramides to their ingredient list, but the content is extremely low (only a "conceptual addition"), and the actual effect is minimal. The method of judgment is simple: look at the position of ceramides in the ingredient list – according to the "Cosmetic Ingredient Labeling Standards," ingredients are listed in order of content from high to low. If ceramides are listed after fragrances and preservatives, it means the content is likely less than 1%, and the effect is limited.
In addition, the "penetration power" of the formula is also very important: ceramides are large lipid molecules, and simply adding them makes it difficult for them to penetrate the stratum corneum. It is recommended to choose products containing penetration-enhancing ingredients (such as panthenol, hyaluronic acid) or those using "liposome encapsulation technology," which allows ceramides to be more easily absorbed by the skin and exert their repair function. 3. Consider skin type compatibility: Avoid products that may cause adverse reactions.
Sensitive skin/Dry skin: Prioritize ceramide creams and lotions. These have a thicker texture, strong moisturizing and repairing properties, and should be free of alcohol, fragrances, and preservatives (such as methylisothiazolinone MIT) to minimize irritation;
Oily skin/Combination oily skin: Choose ceramide serums and toners. These have a refreshing, non-greasy texture that repairs the skin barrier without overburdening the skin;
Post-cosmetic procedure/Severely damaged skin barrier: It is recommended to choose products with a "single ceramide + simple formula" (such as only containing ceramide 3 + panthenol) to avoid complex ingredients that may cause skin intolerance.
