Dialogue with ZHANG Yuguang: When we talk about the "youthful state" in medical aesthetics, what exactly are the standards?

In 2025, the domestic medical aesthetics market stands at a crucial point.

The public's demand for anti - aging and rejuvenation is increasing day by day. The aesthetic trend has also shifted from blindly following the trend in the past to pursuing natural "mother - like beauty" and "Eastern beauty."

Along with the continuous rise in personalized and refined medical aesthetics demands, there has been a boom in the renewal of products and materials on the supply side. From the classic application of hyaluronic acid to the successive approval of collagen - stimulating materials (such as PLLA Sculptra) and collagen for the market, consumers seem to have a particularly rich choice.

However, there are also many hidden concerns behind the prosperity. On social media, negative cases such as "moon - face effect" (excessive facial filling), a fake - looking face, and displacement have discouraged many people.

So, how should we objectively measure the "youthful state" change before and after medical aesthetics? In the eyes of clinical doctors, what are the characteristics of the main biological materials used for medical aesthetics repair? What are the core reasons for the "moon - face effect" and a fake - looking face?

In response to a series of questions, 36Kr recently interviewed Professor Zhang Yuguang, the chief physician of the Department of Plastic and Reconstructive Surgery at the Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine. From the perspective of a clinical expert, he shared the objective standards for facial rejuvenation, the in - depth logic of "moon - face effect" repair, and the key factors for enhancing the medical aesthetics experience.

The following is the edited conversation:

Setting objective standards for the "youthful" aesthetic

36Kr: According to your observation, what significant changes have occurred in the public's aesthetic trends and demands?

Zhang Yuguang: I believe that in the past 20 years, the Chinese medical aesthetics market has gone through a process from "blindly following the trend" to "self - awakening." Twenty years ago, many people wanted to have the same big eyes and high nose as a certain celebrity. But later, people found that due to different bone structures, blind imitation often led to facial disharmony.

The current trend is to pursue natural beauty and a mother - like look. People have realized that the "youthful state" is the core of beauty. This shift from local organ plastic surgery to overall rejuvenation and skin improvement is, in my opinion, a sign of aesthetic maturity.

36Kr: In the past, evaluating whether a person was "younger (than their actual age)" was often based on subjective feelings. From a medical professional perspective, is there a more objective evaluation standard for facial rejuvenation?

Zhang Yuguang: In the past, the industry lacked a unified objective standard for "facial rejuvenation." In recent years, we have introduced two important objective indicators to help doctors and patients define "youth" from an anatomical perspective.

First, there is the concept of the "facial fold line." Why do Westerners seem to have a more three - dimensional face? Because their facial fold lines are clear. The position of this fold line is: draw a vertical line upward from the outer side of the eyebrow peak, extend it upward to the temporal fossa, and downward through the zygomatic arch. This fold line divides the face into two regions: the anterior face and the lateral face, with completely different organizational structures and aging mechanisms in the two regions.

The anterior face is also the area where facial expressions are concentrated. Daily expressions such as laughing and crying mainly rely on this area. The soft tissue and fat layer in the anterior face area are relatively thick, and the core aging feature is the gravitational sagging of fat.

The lateral face is also a functional area. For example, our masseter muscles are located in the lateral face. The tissues in this area are relatively thin, and aging is mainly manifested as the relaxation of the skin and fascia system.

The second important objective indicator is the "facial contour line." The famous anatomist Mendelson discovered that there is a clear ligament connection line on the face. The upper part of this line coincides with the facial fold line we mentioned, and the lower part extends forward to the anterior edge of the mandibular ligament. This ligament line is the benchmark for dividing the "inner and outer facial contour lines."

As people age, the inner contour area of the face will become flat or even sunken, and the lateral canthus (the outer corner of the eye) is just located at the edge of the line. This change is because the fat on the face sags and loses, causing the originally plump curve to become a straight line.

Therefore, one of the treatment goals for rejuvenation is to restore the inner contour line from a "straight line" to a plump, upward and forward - protruding "curve" through volume supplementation and repositioning.

For the outer contour, the rejuvenation standard is the opposite: changing from a curve back to a straight line. The outer contour mainly refers to the area from in front of the ear to the mandibular margin. When we often say that "the mandibular margin is not clear," it is essentially a problem with the outer contour.

There are two reasons for the wavy curve of the outer contour: one is the extrusion and accumulation caused by the sagging of the anterior face fat, and the other is the local accumulation caused by the relaxation of the lateral skin and fascia.

So, the treatment goal for the outer contour is to repair the "wavy curve" formed by relaxation and sagging into a firm "straight line." This is the relatively objective "facial rejuvenation" evaluation system I proposed. Medical aesthetics repair for rejuvenation can be summarized as: changing the inner contour line from straight to curved, and changing the outer contour line from curved to straight.

The development trend of medical aesthetics biological materials

36Kr: It's like providing a "yardstick" for medical aesthetics in terms of aesthetics. But in actual operation, when users choose hyaluronic acid for facial filling and rejuvenation repair, they are particularly worried about some side effects, such as the "moon - face effect" and displacement. Do you think it is caused by the injection material or improper operation?

Zhang Yuguang: At present, among various fillers, I think hyaluronic acid has unique advantages. First, it is part of our own tissue, with high safety, and there is a wealth of clinical trial data and real - world research data. Second, it is effective. After hyaluronic acid injection, immediate results can be obtained. Third, the injection result is predictable. Fourth, the result is reversible. If you are not satisfied with the result, you can dissolve the filler with hyaluronidase.

Problems such as the "moon - face effect" are not caused by the hyaluronic acid filler itself. The core reasons lie in improper operation, excessive injection, or the use of non - regular products.

In response to this situation, the logic of current repair treatments has been further improved. In the past, doctors might simply take a "subtraction" approach, that is, pumping out or dissolving the filler. However, the actual results show that after simply removing the material, the patient's facial condition is still not ideal.

This involves an important mechanism at the cellular level called the "contact inhibition effect." In normal tissues, cells are closely adjacent to each other. This physical contact generates inhibitory signals to prevent excessive cell proliferation. But when physical voids are left after pumping or dissolving the material, lymph fluid will accumulate in these cavities. Because cells lose the contact inhibition between each other, in order to fill the voids, they will start pathological proliferation.

This explains why for some people, after pumping or dissolving the filler, the "moon - face effect" is not only not solved, but rebounds more severely due to tissue proliferation or fluid accumulation.

Therefore, the current logic for treating the "moon - face effect" is: first pump out or dissolve the material, and then, through technical means, reposition the tissue to a youthful and firm state. By doing this, on the one hand, it restores the natural contour of the person seeking beauty in terms of appearance. On the other hand, physiologically, it closes the gaps through compaction and repositioning, making the tissues closely fit together and allowing cells to regain "contact inhibition," thereby reducing later pathological proliferation.

36Kr: What is the reversibility of other biological materials that can be used for filling after injection?

Zhang Yuguang: The treatment of hyaluronic acid is relatively simple. It has a dissolving enzyme, and as a hydrophilic material, it can be effectively treated in combination with pumping and dissolving. However, the repair after injection of collagen stimulants (such as PLLA, PCL, etc.) is more challenging. Because this type of material achieves the filling effect by stimulating the growth of the body's own tissues. Once injected in excess, forming hard lumps or nodules, since it is highly compatible with the body's own tissues and does not have a specific dissolving enzyme like hyaluronic acid, it is relatively difficult to handle.

36Kr: Many experts have mentioned the combined use of collagen regeneration stimulants (such as PLLA) and hyaluronic acid. Is this the mainstream trend in the future?

Zhang Yuguang: The core of whether to choose combined use lies in the beauty seeker's expectation of the effect. I usually ask patients: Do you expect immediate results or long - term results?

If you are pursuing "immediate results" and hope to see plump apple muscles and a well - defined contour in a very short period of time (for example, you have an event tomorrow), then hyaluronic acid is the best choice. Because it has strong predictability - you can see the exact effect immediately after injection. At the same time, it is repairable, and you can dissolve it if you are not satisfied.

If you are pursuing "long - term results," then you can choose collagen stimulants. This type of product takes 1 - 2 months or even longer to stimulate the growth of your own collagen. Of course, after injection, the amount of collagen growth will be affected by individual factors (such as whether you are a scar - prone person and your own metabolic level), so there is a certain degree of uncertainty.

For beauty seekers who want both short - term results and long - term firmness and naturalness, my experience is to carry out "zoned treatment." Hyaluronic acid can be tried on the anterior face (the expression area), and collagen stimulants can be considered for the lateral face (the support area). Because the main goal of the lateral face is to achieve skin tightening and compaction, and the firming effect produced by collagen stimulants can be brought into play.

36Kr: There are constantly new concepts emerging in the medical aesthetics market. What suggestions are there for consumers to avoid marketing traps?

Zhang Yuguang: I often tell patients that medical aesthetics fillers are different from cosmetics. You can throw away cosmetics if they are not good, but once fillers enter the tissues, some are extremely difficult to correct.

Therefore, I have two suggestions: First, don't easily be a "guinea pig." As a doctor, when choosing products, I first choose products that are regular and strictly within the scope of indications. I need to see if the product has at least 10 years of clinical retrospective research. Only products that have been verified by long - term and large - scale clinical trials and have guaranteed safety and stability can be used on the faces of beauty seekers.

Second, choose the right doctor. It is recommended to find a professional doctor who has received formal medical education and whose advice is not solely based on sales performance. If a doctor's advice is based on performance considerations rather than medical needs, medical decisions are likely to be biased.

The ultimate experience of medical aesthetics depends on three factors: product quality, the aesthetic sense of the beauty seeker, and the doctor's skills and aesthetic sense. The product is the foundation. Branded products with complete clinical data determine the baseline of the experience, while the doctor's level determines the upper limit. Therefore, continuous doctor education (such as the training provided by Allergan Academy) is particularly important.

In addition, it is also crucial for consumers to improve their aesthetic awareness. Only on the premise of respecting the anatomical basis and pursuing personalized solutions can the unity of safety and beauty be truly achieved.