A: Internal factors include hormones and sebum secretion, while external factors are primarily UV radiation, diet, and cleansing habits. Up to 80% of facial aging (wrinkles, sagging, hyperpigmentation, and roughness) is caused by UV rays from the sun (photoaging). Consuming excessive high-sugar foods and dairy products will stimulate sebum secretion and trigger glycation, leaving the skin inelastic, yellowish, and dull. Additionally, staying up late and chronic stress will cause hormonal fluctuations, leading to breakouts and a dull complexion.
　　Basic skincare: moderate cleansing, moisturizing, and sun protection. If you have severe issues with acne, blackheads, or oiliness, you can layer on an active serum or ointment. Adhere to a low-sugar diet, drink less milk (yogurt is fine), maintain a regular sleep schedule, and drink plenty of water.
　　Before age 25, focus on oil and acne control to avoid post-acne erythema (red marks) and atrophic scars (pitting). Strict sun protection is required.
　　From 25 to 35, focus on antioxidation and early-stage anti-aging. On top of your basic routine, you can incorporate antioxidant ingredients and retinoic acid (Vitamin A).
　　Age 35 and above: high-concentration anti-aging ingredients and medical aesthetics / cosmetic procedures.

A: The ingestion of high-sugar foods (foods with a high glycemic index) and dairy causes a sharp spike in insulin and Insulin-like Growth Factor-1 (IGF-1) levels. IGF-1 plays a dominant role in regulating sebum secretion; it stimulates sebaceous glands, leading to a massive increase in oil production, while simultaneously promoting the hyperproliferation of keratinocytes, which clogs pores and triggers comedones (acne). A high-sugar diet induces glycation. When you consume excess sugar, free sugar molecules bind to collagen and elastin in the dermis without the action of enzymes, forming Advanced Glycation End-products (AGEs). AGEs cause collagen to cross-link, making it stiff, brittle, and devoid of elasticity. This directly results in skin sagging and photoaging wrinkles. Furthermore, glycated collagen turns yellow, leading to a dull, sallow complexion that is extremely difficult for the body to degrade and repair.
The mechanism of milk's harm: Milk naturally contains various hormones necessary for a calf's growth, especially abundant IGF-1, insulin, and growth hormones (its structure differs from human growth hormone, so don't harbor illusions of growing taller). Moreover, milk contains casein, which turns into curd under the action of stomach acid. This protects IGF-1 from being destroyed by stomach acid, allowing it to enter the intestines, be absorbed into the bloodstream, and directly stimulate sebaceous glands to produce oil. Furthermore, while milk's glycemic index isn't high, its insulinogenic index is extremely high. Its whey protein contains massive amounts of branched-chain amino acids (BCAAs) that promote insulin secretion, leading to IGF-1 secretion. Studies have found that skim milk has an even higher correlation with acne than whole milk because the processing alters the hormonal ratios. The fermentation process of yogurt degrades most of these hormones.
Minimize refined carbohydrate intake, such as milk tea, sugary sodas, desserts, white rice, etc. Replace white rice and refined flour with whole grains whenever possible. Eating until you are 80% full per meal is sufficient; moderately restricting caloric intake helps control acne and acts as an anti-aging measure. Supplement with Omega-3 polyunsaturated fatty acids, which possess anti-inflammatory properties. It is recommended to eat salmon or tuna 3 times a week; daily intake can include flaxseed oil and walnuts, with an optimal supplementation of 10–15 grams daily. Some scholars suggest adopting the Eastern "steaming and boiling" cooking methods as much as possible, as these generate exceptionally low levels of AGEs (glycotoxins). Avoid "grilling, baking, and frying" as much as possible; for instance, fried potatoes contain 87 times more AGEs than boiled potatoes. Avoid drinking pure milk whenever possible (especially skim milk). If acne is severe, you must also moderately reduce animal-based foods high in leucine, such as beef and cheese. Protein can be sourced from soy milk, tofu, eggs, and fish. For dairy, choose sugar-free yogurt or yogurt with sugar substitutes. Drink 2–4 cups of green tea daily. Green tea is rich in polyphenols, which not only act as antioxidants but also inhibit 5α-reductase, thereby reducing sebum secretion. Depending on how much you sweat, consume 1-2L of water daily to promote metabolism.

A: They all target the monosaccharides that result from the breakdown of disaccharides or polysaccharides. Glycation involves glucose and fructose, which are reducing sugars. In the absence of enzymes, they attach to the amino acid side chains of proteins in the dermis. Insulin and IGF-1 fluctuations are triggered by glucose.
In terms of glycation, fructose is vastly more destructive. Therefore, items like milk tea with added high-fructose corn syrup are far more damaging than rice.
Both GI (Glycemic Index) and total sugar content must be considered. High GI leads to massive secretions of insulin and IGF-1. High total sugar content provides the raw materials for glycation, ultimately still inducing insulin resistance.

A: Many grilled, baked, and fried foods contain extremely high levels of Advanced Glycation End-products (AGEs)—far higher than boiled or steamed foods. AGEs directly enter the bloodstream and attack the collagen and elastin in the dermis. Fats also lead to the generation of AGEs. Excessive intake of high-fat, fried, and animal-based foods easily leads to obesity, inflammatory responses, and the disruption of the gut microbiome.
Unhealthy greases (saturated fats and excessive Omega-6) lead to more vigorous sebaceous gland secretion on an endocrine level. Sebum dilutes the linoleic acid essential for hair follicles, causing a lipid deficiency that weakens the follicular epithelial barrier function and triggers follicular hyperkeratosis. However, Omega-3 polyunsaturated fatty acids have anti-inflammatory effects.

A: Seeking alternatives is recommended, though specific literature is temporarily lacking.

A: Insufficient sleep duration and chronic fatigue lead to poor facial microcirculation and reduced hemoglobin levels, causing the blood vessels around the eyes to appear bluish and forming dark circles. Lack of sleep can cause dry skin, chapped lips, and fine lines around the eyes.
Different bedtimes involve the circadian rhythm. The stress induced by staying up late activates the HPA axis (hypothalamic-pituitary-adrenal axis), secreting cortisol, DHEA (Dehydroepiandrosterone), etc., which stimulates oil secretion and inhibits epidermal lipid synthesis, leading to breakouts and skin fragility.
According to the gut-brain-skin axis theory, chaotic routines and irregular eating habits easily lead to gut dysbiosis (microbiome imbalance) and constipation. Once constipation occurs, harmful microbes in the gut multiply rapidly, and endotoxins can easily penetrate the large intestine wall into the bloodstream, triggering systemic inflammation and insulin resistance, which exacerbates sebum secretion and inflammation.

A: Creams and lotions are essential, serums are optional, and abandon sheet masks entirely. Creams and lotions primarily consist of water, oil, and emulsifiers, preventing moisture loss and maintaining the skin barrier. They are a vital part of basic skincare; you may opt for lightweight lotions or gel creams. Serums mainly contain high concentrations of active ingredients. Sheet masks only macerate the stratum corneum, which can actually compromise the skin barrier.
Adapalene is a third-generation retinoid medication. It corrects abnormal follicular keratinization, dissolves comedones, controls oil, and stimulates new collagen production in the dermis, showing excellent clinical data in preventing photoaging and fighting acne. Benzoyl Peroxide (BPO) is a potent oxidizing agent that kills Cutibacterium acnes with fast results. However, the free radicals generated when BPO breaks down lead to oxidative stress, which may damage DNA and accelerate skin aging. It is only recommended for spot-treatment in emergencies.
Creams/Lotions: For humectants, choose products containing glycerin, hyaluronic acid, and urea. For occlusives, avoid petrolatum (Vaseline), heavy mineral oils, cocoa butter, and heavy plant oils; choose dimethicone and other silicone-based ingredients. It is recommended to seek out Niacinamide as an additional ingredient, as it simultaneously moisturizes, controls oil, and fights early aging.
For sun protection, chemical sunscreens are preferred. Prioritize Asian and European brands to avoid greasy ingredients like Avobenzone. For daily commuting, choose SPF 30 to SPF 50, and PA+++ to PA++++, or look for the "Broad Spectrum" label.
Soap-based cleansers contain fatty acids and sodium/potassium hydroxide. They have strong cleansing power but a high pH, which destroys the skin's naturally acidic environment. Furthermore, highly alkaline soap bases not only cause skin proteins to swell but also strip away massive amounts of intercellular lipids, such as cholesterol, which maintain the skin barrier. Long-term use easily leads to an impaired barrier, making the skin sensitive, dry, and paradoxically more oily. Amino acid cleansers contain ingredients like Potassium Cocoyl Glycinate and Sodium Cocoyl Glutamate, with a weakly acidic pH.
Daily sunscreens without ultra-strong water resistance can be washed off completely with a standard cleanser.
When cleansing, lather first, then massage in circular motions, paying special attention to the forehead, nose, and hairline. Wash by hand whenever possible. The massaging duration should not be less than one minute. Lukewarm water is optimal. The amount used should be enough to whip up a rich, fine foam in your palms that can cover the entire face.

A: UVA (long-wave UV) destroys collagen and elastin, leading to skin sagging and wrinkles, and triggers persistent melanin pigmentation. UVB (short-wave UV) causes acute sunburns, erythema, delayed tanning, and skin cancer. It can be blocked by glass.
The intensity of UVB is heavily influenced by season and time of day, peaking in summer and between 10 AM and 4 PM daily. UVA is less affected by seasons; autumn and winter UVA intensity can still reach about 50% of summer levels. Combined with the change in the sun's angle, the radiation dose received remains at about 30% of summer levels. Clouds only block visible light; most UVB and UVA can still penetrate cloud cover.
The ABC Principle: Avoid: Try not to be exposed to sunlight between 10 AM and 4 PM when UV rays are strongest. Block: A standard dark-colored umbrella blocks over 85% of UV rays; professional UV-blocking umbrellas, wide-brimmed hats, or UPF clothing can even block 95%–100% of UV rays. Cream: Sunscreen needs to be applied when physical blocking cannot cover an area or when UV rays reflect off the ground.
The face, neck, outer arms, back of hands, ears, lips, back of the neck, and the eye area must be protected. Additionally, it's recommended to use an SPF lip balm during the day.
The protective film formed by sunscreen on the skin's surface usually only lasts about 2 hours. However, if you are mostly indoors, in class, not sweating profusely, and haven't wiped your face to disrupt the film, frequent reapplication is unnecessary. During outdoor sports, water-resistant products should be reapplied every 40 minutes, and highly water-resistant products every 80 minutes.

A: When UV rays, especially UVA, irradiate the skin, c-Jun and c-Fos combine to form the AP-1 transcription factor. AP-1 induces the production of Matrix Metalloproteinases (MMPs). MMPs (including collagenase, gelatinase, etc.) break down and sever collagen. Furthermore, UV rays directly inhibit fibroblasts from synthesizing new collagen.
UV irradiation triggers the skin to produce Reactive Oxygen Species (ROS), also known as free radicals. Free radicals are highly unstable and lack an electron, causing them to attack normal cell plasma membranes, proteins, and DNA. Additionally, free radicals induce a severe inflammatory response, which leads to a massive secretion of MMPs, further degrading collagen.
Aside from degrading elastic fibers, UV rays also cause abnormal, non-functional elastic fibers to massively proliferate, tangle, and deposit abnormally in the dermis. Medically known as solar elastosis, this makes the skin lose elasticity, becoming rough, thickened, yellowish, and sagging.
UV rays, particularly UVB, can penetrate cells and damage DNA, causing adjacent bases to bind abnormally and form thymine dimers. Meanwhile, UV-induced DNA damage leads to the accelerated shortening of telomeres at the ends of chromosomes and the destruction of circular structures. Once telomeres are degraded to a critical point, the cell stops dividing and heads toward senescence or apoptosis.

A: Mild to moderate photoaging can be reversed to a certain extent. Topical retinoids are currently the only treatment proven through randomized clinical trials to improve the appearance of photoaged skin. Retinoic acids/retinoids can halt UV-induced collagen loss and also stimulate fibroblasts to synthesize new collagen, thereby reversing the fine lines and roughness caused by photoaging. Vitamin C is currently the only known antioxidant ingredient capable of treating and improving existing photoaging wrinkles by promoting collagen formation. AHAs (Alpha Hydroxy Acids) exfoliate the abnormal epidermal stratum corneum damaged by light and promote the synthesis of collagen and hyaluronic acid in the dermis, thickening the dermis. They have a definitive reversal effect on wrinkles, roughness, and uneven pigmentation caused by photoaging. IPL (Intense Pulsed Light), fractional lasers, and radiofrequency (RF) use photothermal energy to destroy the abnormal collagen clumps generated by photoaging, stimulating the skin to initiate a compensatory repair mechanism to synthesize a massive amount of healthy collagen, achieving a bottom-up reversal of photoaging. Imiquimod, as a topical immunomodulator, has been clinically observed to reverse epidermal atrophy, pigmentation anomalies, and wrinkles caused by photoaging by down-regulating destructive enzymes like MMP-9. This claim is found in Baumann's works but lacks cross-verification.
The early stage of glycation involves sugars binding with collagen or elastin to form a Schiff base. It then enters the final stage, where primary products rapidly degrade and cross-link, forming AGEs. Once AGEs are formed, the process is completely irreversible.
In the dermis, fibroblasts synthesize new collagen and degrade the old matrix. However, after a massive accumulation of old collagen denatured by glycation and cross-linked products, it becomes extremely difficult for fibroblasts to completely clear them out. Not only that, the fragmentation of old collagen causes fibroblasts to lose their attachment points, thereby severely interfering with or even obstructing the normal generation and structural assembly of new collagen.

A: Vitamin C is a topical antioxidant that neutralizes free radicals and boosts the efficacy of sun protection. Vitamin A powerfully inhibits sebum secretion, unclogs pores, and stimulates new collagen production. Third- and fourth-generation retinoids have good photostability and can be used during the day.
Vitamin C scavenges free radicals, inhibits tyrosinase activity to block melanin synthesis, reduces oxidized melanin, and acts as a coenzyme to promote collagen synthesis.
Vitamin C can only scavenge free radicals; it cannot block the collagen damage caused by UV rays. Because Vitamin A derivatives increase sensitivity to UV light, sun protection measures are absolutely mandatory. If you rely on physical sun protection (UPF clothing, hats, umbrellas) and don't apply sunscreen in the morning, you should apply a Vitamin C derivative serum and a cream/lotion after cleansing. If you don't use physical sun protection, the moisturizing ingredients in your sunscreen are sufficient. Proceed with your normal evening routine.
Regarding ingredients, avoid pure Vitamin C (L-ascorbic acid). It is highly unstable, requires a low pH to penetrate, feels sticky, and oxidizes yellow. You can opt for Sodium Ascorbyl Phosphate (SAP), which clinical data shows also has acne-fighting capabilities. A concentration around 5% is sufficient. The formulation should be water-based; avoid oil-based or silicone-based formulations.

A: Atrophy and downward displacement of subcutaneous fat, facial bone resorption and remodeling, overdeveloped masseter muscles, and edema (swelling) caused by poor lifestyle habits.
Avoid excessively hard, chewy foods like betel nuts, chewing gum, and beef jerky. Maintain a stable weight, minimize staying up late, and persist in sun protection and anti-aging routines.
Repeated muscle pulling causes facial wrinkles. Nerve signals transmitted to muscles cause contractions; after repeating this tens of thousands of times, it directly leads to the degradation and rearrangement of collagen and elastic fibers in the dermis, eventually forming a solidified alignment. Expression management is useful for preventing dynamic wrinkles—for instance, reducing hearty laughing, frowning, and squinting. However, it is ineffective at preventing the drooping of fat pads.
Facial muscle exercises, like facial yoga, lack scientific backing and carry the risk of accelerating aging and disfigurement. Medical aesthetic interventions like Botox work by paralyzing and relaxing the muscles; doing the exact opposite will only ruin your face.
Sleeping exclusively on one side or on your stomach applies chronic physical pressure to the face. The orbital fat presents irregular contours, periorbital bones protrude, lower eyelids bulge, the shape of the facial soft tissue framework changes, nasolabial folds deepen, and crow's feet are accelerated. Note: This claim lacks cross-verification.

A: The skin around the eyes is thin, lacks sebaceous glands, and moves frequently. A gentle facial lotion can be directly applied to the eye area; eye cream is unnecessary. It is recommended to buffer Adapalene with a layer of lotion first.

A: Androgens such as DHT strongly stimulate the sebaceous glands, leading to oil production. In terms of wound healing and skin repair, estrogen generally promotes angiogenesis and tissue repair, whereas androgens have the opposite effect.

A: IPL (Intense Pulsed Light) is effective; it targets melanin and hemoglobin and stimulates collagen production. Radiofrequency (RF) lifting is effective, but microcurrent/massage devices are essentially psychological placebos. Comedone extractors are effective, but they can only be used for blackheads and closed comedones; they are useless against inflamed red pimples. Infusion devices help increase the absorption rate of skincare products, but they are a hassle.
Comedone extractors must be sterilized. For open comedones (blackheads), use the loop of one extractor to frame the blackhead and push it upward, use the needle tip of another to detach the keratin plug from the pore walls, and finally use two loops to press on both sides of the blackhead to extract it. Squeezing with fingers easily causes the follicle to rupture internally, triggering an inflammatory response. For closed comedones (whiteheads), pierce with the needle tip, then extract with the loop.
Causes of blackheads and closed comedones: Excess sebum combined with dead skin cell buildup forms a non-inflammatory physical blockage. Open comedones look black due to optical effects or vellus hair; closed comedones have white sebum plugs because the surface is sealed by hyperproliferative cells. Red, swollen pimples: Overgrowth of Cutibacterium acnes triggers an inflammatory response. Red atrophic scars (pitting): During severe inflammation, inflammatory cells release matrix metalloproteinases and hyaluronidase, which degrade the support structures in the dermis like collagen and elastic fibers.
For red, swollen pimples: Spot-treat with Benzoyl Peroxide. For blackheads: Use a comedone extractor and Salicylic Acid. For whiteheads: Use an extractor and spot-treat with Retinoic Acid to inhibit the hyperproliferation of follicular cells. For red post-acne scars: Reduce inflammation, and leave the rest to fate.
Fingernails can easily damage the epidermis and apply uneven pressure. This claim lacks cross-verification.
There is no evidence proving alcohol disinfection is required. After extracting blackheads, disinfection is necessary. Dr. Binghan explicitly mentions phrases like "successfully extract the keratin plug, then disinfect the skin" and "pay attention to disinfection before and after extraction." However, this claim lacks cross-verification. If you are worried about irritation, you can use colloidal silver or hypochlorous acid (these two lack cross-verification), or use Salicylic Acid (being an acid, it inherently possesses some antibacterial properties).
After extracting blackheads, use Salicylic Acid to dissolve the sebum plug and exfoliate dead skin, inhibiting recurrence. After extracting whiteheads, spot-treat with Retinoic Acid to inhibit cell proliferation and correct abnormal keratinization. Erythromycin, as an antibiotic, is useless here and inferior to Benzoyl Peroxide.
For areas with dense blackheads, you can use a comedone extractor to scrape away sebum-plug type blackheads after a hot shower, and use a peel-off mask to pull out keratin-plug type blackheads, but do not do this frequently. Afterward, use Salicylic Acid to inhibit them. This claim lacks cross-verification.
Layering Retinoic Acid and Salicylic Acid will drastically increase the chances of skin irritation and dryness. It is recommended to use them on different zones of the face, or just stick to Retinoic Acid for daily use.
Holes that are not inflamed or purulent are reversible. This claim lacks cross-verification.

A: No remedy is needed. A long-term foundation of a healthy diet is sufficient to withstand occasional indulgences.
If you insist on damage control, you can drink green tea, consume Omega-3s, and supplement with Vitamin C.

A: Remedial measures are necessary. First, physically cool down by applying cold water compresses to your face, or use a toner containing chamomile, purslane, or cactus extract to constrict blood vessels and block the release of inflammatory cytokines. Use antioxidants: drink green tea, and apply or ingest Vitamin C and Vitamin E. Furthermore, avoid using Salicylic Acid, AHAs, high-concentration Vitamin C, Azelaic Acid, or other exfoliating or highly irritating ingredients after a sunburn.

A: Omega-3s possess anti-inflammatory properties, improve acne and facial redness, lock in moisture, and prevent photoaging. Baumann recommends supplementing about 1000mg of Omega-3 daily; Binghan suggests consuming 10-15g of oils rich in polyunsaturated fatty acids daily.
Multivitamins and Minerals: Zinc can inhibit 5α-reductase, thereby reducing sebum secretion, and fighting inflammation and acne. Vitamin B3 (Niacinamide) and B6 can control oil and fortify the skin barrier.
Ubiquinol (reduced CoQ10) is a core substance for ATP generation and a fat-soluble antioxidant. It can delay skin aging and reduce wrinkles. Clinical recommendations are often 200-400mg taken in the morning. However, the human body's own ability to synthesize CoQ10 doesn't significantly decline until after ages 35-40.
Glucosamine Chondroitin is only recommended by Baumann, who believes glucosamine is a precursor to the synthesis of hyaluronic acid, increasing skin hydration and reducing wrinkles. The recommendation is to take 1500mg daily, especially for those over 35. Cannot be cross-verified.
Creatine is not mentioned in the sources.
Vitamin C is a coenzyme for synthesizing collagen, while also providing antioxidant, anti-inflammatory, and brightening (scar-fading) effects. Baumann recommends 500mg orally twice a day; Binghan recommends smaller, frequent doses totaling 200-400mg daily, while simultaneously eating more fruits and vegetables rich in Vitamin C.