Learning Center: SKIN REGIMEN

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FUNDAMENTALS ON SKIN MAINTENANCE

In brief: How skin looks over a lifetime depends far more on a few daily habits than on expensive products. Daily sunscreen, avoiding tobacco, gentle cleansing, a moisturizer, and a topical retinoid are the measures with the best evidence; in a randomized trial, daily sunscreen use alone slowed visible skin aging by about a quarter over four and a half years [1]. This page explains those fundamentals and then covers the common conditions that affect the appearance of the skin (acne, rosacea, wrinkles, and pigment changes), with a summary of current, evidence-based treatment for each. Procedures such as resurfacing, injectables, and surgery build on these fundamentals but do not replace them.

Frequently, people will focus their time and money on minor aspects of skin care while ignoring the much more important fundamentals. Cosmetic and “cosmeceutical” companies abound with high priced oils and herbal infused creams but with little to no scientific evidence supporting a benefit; for many popular cosmeceutical ingredients, controlled clinical trials are few, small, or absent [2]. Fragrance additives are common, which may add to the placebo effect, but may also create skin irritation. Fragrance ingredients are among the most frequent causes of allergic contact reactions to cosmetics, and an estimated 1.7 to 4.1 percent of the general population is sensitized to them [3]. While the result may be positive, it may be neutral or even harmful to skin health. It is usually unhelpful for financial health. Here are the fundamentals for good skin care:

  • Avoid sun (ultraviolet light) exposure.

  • Avoid nicotine and tobacco.

  • Use proven skin care products:

    • Wash your face with a simple soap or a gentle, fragrance-free cleanser. Harsh detergents and high-pH (alkaline) products strip the lipids and proteins of the outer skin barrier and cause tightness, dryness, and irritation [4].

    • Moisturize your face daily. Moisturizers reduce water loss from the outer skin layer; their composition matters, and some formulations strengthen barrier function more than others [5].

    • Manage acne if needed.

    • Manage pigmentation irregularities if desired.

    • Use a retinoid (retinol or, for a stronger effect, prescription tretinoin).

  • Be diligent. Do the above every day. An ounce of prevention is worth a pound of cure.

  • Also, consider using an injectable neurotoxin for facial wrinkles. Neurotoxins and fillers are described in more detail on the injectables Learning Center page.

Retinoids: the best-studied topical treatment for aging skin

Retinoids are vitamin A derivatives. Tretinoin (retinoic acid, available by prescription) is the most potent and most widely studied retinoid for photoaging; retinol and retinaldehyde, sold over the counter, are converted to retinoic acid in the skin and are considerably less irritating but also less potent [6].

  • In the first double-blind trial, 14 of 15 patients who applied tretinoin to the face for 16 weeks improved, compared with none who applied the inactive cream [7].

  • A Cochrane review of randomized trials found tretinoin at concentrations of 0.02 percent or higher superior to placebo for mild to severe photodamage; for 0.05 percent cream, the chance of improvement at 24 weeks was about 1.7 times that with placebo. Both benefit and irritation rose with concentration [8].

  • In a 48-week trial, 0.025 percent and 0.1 percent tretinoin produced similar improvement, but the higher strength caused significantly more redness and peeling [9]. Higher strength is therefore not necessarily better.

  • Over-the-counter retinol has a smaller evidence base. In a randomized, vehicle-controlled trial in elderly adults, 0.4 percent retinol improved fine wrinkling and increased collagen production after 24 weeks [10].

A pea-sized amount applied at night, starting every second or third night and increasing as tolerated, limits the dryness and peeling that cause many people to stop. Retinoids make the skin more sensitive to sunlight, which is one more reason for daily sunscreen. Retinoids are usually stopped during pregnancy.

SUN PROTECTION

Ultraviolet light, whether from the sun or a tanning bed, causes mutations in the DNA of the skin, leading to accelerated aging and possible cancer. Ultraviolet exposure also activates enzymes (matrix metalloproteinases) that break down the collagen of the dermis while suppressing new collagen production; repeated over years, this damage accumulates as photoaging [11]. Keep in mind that there is no such thing as a healthy tan, and the healthiest skin on a middle-aged or older individual is typically on the buttocks, where sun exposure has been truly minimal. Tanning beds are not a safe alternative: in a meta-analysis of 27 studies, ever using a sunbed raised the risk of melanoma by about 20 percent, and first use before age 35 raised it by about 87 percent [12]. Consider these facts:

  • Most visible facial aging in fair skin is caused by the sun. In a study of 298 women comparing sun-seekers with sun-avoiders, ultraviolet exposure appeared responsible for about 80 percent of visible facial aging signs, especially wrinkles and uneven pigmentation; sagging, by contrast, was mainly a result of chronological aging [13].

  • People who use sunscreen with an SPF of 15 or higher daily show 24 percent less skin aging than those who do not use sunscreen daily. This comes from a randomized trial of 903 Australian adults under age 55: over four and a half years, the daily-sunscreen group showed no detectable increase in skin aging [1].

  • Sun damage is cumulative. Americans receive less than 25 percent of their lifetime ultraviolet dose by age 18, not the 80 percent that was widely quoted for many years, so protection matters throughout adult life [14].

The same Australian trial showed that daily sunscreen also prevents skin cancer. Participants assigned to daily sunscreen developed about 39 percent fewer squamous cell carcinomas [15], and over ten years of follow-up they had about half as many new melanomas, with a larger reduction in invasive melanoma [16]. Sunscreen is an essential part of photoprotection, but not the only part; shade, hats, and clothing add protection, especially during peak hours. In the trials described above, participants applied a broad-spectrum (UVA and UVB) SPF 15-plus sunscreen every morning to the face, neck, arms, and hands; most dermatologists now advise SPF 30 or higher, applied generously and reapplied during prolonged time outdoors.

Sun ultraviolet intensity is greatest between 10 am and 2 pm. Distance from the equator not only reduces overall solar intensity, but it also increases the seasonal variation. In central Illinois, protection from solar radiation is most important from mid-Spring to mid-Fall.

Because sun-damaged skin is also at risk for skin cancer, regular self-examination is worthwhile. See melanoma self-screening and the Learning Center page on skin cancer.

ACNE

Acne, also known as acne vulgaris, is a long-term skin disease that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and possible scarring. It primarily affects skin with a relatively high number of oil glands, including the face, upper part of the chest, and back. The resulting appearance can lead to anxiety, reduced self-esteem, and, in extreme cases, depression or thoughts of suicide. In a population study of 3,775 Norwegian 18- and 19-year-olds, those with substantial acne were about 1.8 times as likely to report suicidal thoughts, even after accounting for depressive symptoms [17].

Causes

Genetics is the strongest single factor. Twin studies estimate the heritability of acne at about 80 percent; in a study of more than 4,000 Australian adolescent twins, heritability of acne severity was 85 percent [18, 19]. Acne also starts earlier and is more severe in people with a family history [18]. In both sexes, hormones called androgens appear to be part of the underlying mechanism, by causing increased production of sebum. Another common factor is the excessive growth of the bacterium Cutibacterium acnes, which is present on the skin.

The role of diet and cigarette smoking in the condition is unclear, and neither cleanliness nor exposure to sunlight appears to play a part [18]. Scrubbing harder does not clear acne and may irritate the skin. On diet, the evidence is limited but suggestive: in a small 12-week randomized trial in young men, a low-glycemic-load diet (fewer sugars and refined starches) reduced lesion counts more than a conventional diet [20], and a meta-analysis of observational studies found milk and other dairy intake associated with roughly 25 percent higher odds of acne, although those studies were heterogeneous and subject to bias [21]. The 2024 American Academy of Dermatology guideline did not make a dietary recommendation [22].

Treatment

Treatments for acne are available, including lifestyle changes, medications, and medical procedures. The 2024 American Academy of Dermatology (AAD) guideline, based on a systematic review with formal grading of the evidence, makes these recommendations [22]:

  • Strongly recommended: topical benzoyl peroxide, topical retinoids (such as tretinoin, adapalene, and tazarotene), topical antibiotics (such as clindamycin), and oral doxycycline.

  • Conditionally recommended: topical azelaic acid, salicylic acid, and clascoterone (a topical androgen blocker); oral minocycline and sarecycline; combined oral contraceptive pills; and spironolactone, a hormonal treatment for women.

  • Oral isotretinoin is strongly recommended for acne that is severe, is causing scarring or psychosocial burden, or has failed standard oral or topical therapy. Because isotretinoin causes severe birth defects, its use requires strict pregnancy prevention, and it is reserved for these situations due to its greater potential side effects.

  • Good-practice statements: combine topical treatments that work by different mechanisms; limit the duration of oral antibiotics; always pair an oral or topical antibiotic with benzoyl peroxide or another topical agent, because resistance to antibiotics may develop as a result of antibiotic therapy; and inject large, painful nodules with a small dose of corticosteroid.

Most mild acne responds to a topical retinoid, benzoyl peroxide, or both, used consistently for at least 8 to 12 weeks before judging the result. Early and effective treatment of acne is important to decrease the overall long-term impact on individuals, including permanent scarring and the dark marks of post-inflammatory hyperpigmentation discussed below. Established acne scars can be improved with procedures described on the scar treatment page.

How common is acne?

Acne is among the ten most prevalent diseases worldwide, with an estimated 9.4 percent of the global population affected [23]. A 2019 Global Burden of Disease analysis estimated 231 million people with active acne at any time, a number that had risen about 48 percent since 1990 [24]. Acne commonly occurs in adolescence, when it is nearly universal; moderate-to-severe acne affects about 20 percent of young people [18]. Some isolated non-industrialized populations have been reported to have little or no acne [23]. Children and adults may also be affected before and after puberty. Although acne becomes less common in adulthood, it persists into the twenties in about 64 percent and into the thirties in about 43 percent of affected people [18]. Adult acne is more common in women: in one survey, 26 percent of women in their forties reported acne, compared with 12 percent of men [25].

ROSACEA

Rosacea is a long-term skin condition that typically affects the face. It results in redness, flushing, acne-like bumps (papules and pustules), swelling, and small and superficial dilated blood vessels (telangiectasias). Often, the nose, cheeks, forehead, and chin are most involved. A red, enlarged nose may occur in severe disease, a condition known as rhinophyma. The eyes are affected in some people, with dryness, irritation, and redness of the eyelid margins.

The cause of rosacea is not fully understood; it appears to involve an overactive innate immune response, abnormal reactivity of blood vessels and nerves, and in some patients an overgrowth of the tiny Demodex mites that normally live in facial hair follicles [26]. Family history matters: in a study of 275 twin pairs, about half of rosacea severity was attributable to genetics and half to environment, with ultraviolet exposure, alcohol, and smoking among the environmental factors identified [27]. Factors that may potentially worsen the condition include heat, exercise, sunlight, cold, spicy food, alcohol, menopause, psychological stress, or steroid cream on the face.

Diagnosis is clinical. International consensus (the ROSacea COnsensus, or ROSCO, panel) has moved away from rigid "subtypes" to a phenotype approach: persistent redness of the central face that periodically intensifies, or thickening of the skin (phymatous change), is each enough for the diagnosis, and each feature a person has (redness, bumps, visible vessels, eye involvement) is assessed and treated on its own [28, 29].

Treatment

While not curable, treatment usually improves symptoms, and the consensus goal is complete clearance rather than partial improvement [29]. Gentle cleansing, daily moisturizer, daily broad-spectrum sunscreen, and avoidance of personal triggers are recommended for everyone with rosacea [26]. A systematic review of 152 randomized trials (20,944 participants) graded the evidence by feature [30]:

  • Persistent redness: high-certainty evidence for topical brimonidine and moderate certainty for topical oxymetazoline, both of which constrict blood vessels temporarily (for hours) and need daily use.

  • Papules and pustules: high-certainty evidence for topical azelaic acid and topical ivermectin; moderate-to-high certainty for low-dose modified-release doxycycline (40 mg) and isotretinoin; moderate certainty for topical metronidazole and for minocycline. Evidence for tetracycline is weaker.

  • Visible vessels and background redness: low-to-moderate certainty evidence for vascular lasers and intense pulsed light (IPL), which are the main options for telangiectasias because medications do not remove established vessels.

  • Eye involvement: moderate-certainty evidence for oral omega-3 fatty acids and lower-certainty evidence for cyclosporine eye drops and doxycycline. Azithromycin has also been used.

For persistent or severe papulopustular rosacea, a meta-analysis of 16 studies (1,445 patients) found that low-dose isotretinoin reduced lesion counts and redness with a large effect, although about a third of patients relapsed within six months of stopping [31]. Combination therapy is recommended when several features are present [29]. Rhinophyma does not respond well to medication; established thickening of the nose is treated by surgical shaving, dermabrasion, or laser surgery [26].

Rosacea affects an estimated 5.5 percent of adults worldwide (5.4 percent of women and 3.9 percent of men), most often between ages 45 and 60 [32]. It is diagnosed most often in people with fair skin, although it occurs in all skin types. The condition was described in The Canterbury Tales in the 1300s.

SMOKING

Smoking affects the skin in many ways, none of them good. Smoking causes accelerated skin aging, decreased wound healing, increased risk of skin infection, and an increased risk of skin cancer.

  • Accelerated aging. In a classic study, heavy smokers (more than 50 pack-years) were about 4.7 times as likely as nonsmokers to have premature wrinkling after accounting for age, sex, and sun exposure, and smoking and sun exposure together multiplied the risk [33]. A systematic review and meta-analysis confirmed smoking as one of the main modifiable risk factors for skin aging, along with sun exposure [34].

  • Evidence from identical twins. Because identical twins share their genes, comparing twins with different habits isolates the effect of the habit. Among 186 pairs of identical twins, the longer a twin had smoked, the older he or she appeared [35]. In 79 twin pairs in which one twin smoked or had smoked at least five years longer, the smoking twin had worse upper eyelid skin excess, lower eyelid bags, nasolabial folds, upper and lower lip wrinkles, and jowls; the changes concentrated in the middle and lower face [36]. A published case of identical twins with matched lifetime sun exposure, only one of whom smoked, shows the same pattern [37].

  • How it happens. Tobacco smoke generates oxidative stress, reduces collagen production, and increases the matrix metalloproteinase enzymes that break down collagen and elastic fibers [38].

  • Skin cancer. In a meta-analysis, smoking increased the risk of cutaneous squamous cell carcinoma by about 50 percent (odds ratio 1.52), although it did not appear to change the risk of basal cell carcinoma [39].

  • Wound healing. Smoking reduces tissue oxygen and impairs the inflammatory and repair cells that heal wounds. After stopping, tissue oxygenation recovers quickly and inflammatory cell function largely within about four weeks, although collagen-producing repair remains impaired for longer [40]. This is why stopping smoking well before facial surgery is so important.

Here is a link for additional information on how smoking affects the skin.

WRINKLES

A wrinkle, also known as a rhytide, is a fold, ridge or crease in an otherwise smooth surface, such as on skin or fabric. Skin wrinkles typically appear as a result of aging processes such as glycation, habitual sleeping positions, loss of body mass, sun damage, or temporarily, as the result of prolonged immersion in water. Age wrinkling in the skin is promoted by habitual facial expressions, aging, sun damage, smoking, poor hydration, and various other factors. In humans, it can also be prevented to some degree by avoiding excessive solar exposure and possibly through diet. Observational studies have linked diets rich in vegetables, legumes, olive oil, and vitamin C to less wrinkling, and diets high in fat, sugar, and refined carbohydrate to more [41, 42]. These are associations rather than proof, and no supplement has been shown to prevent wrinkles; in the Australian sunscreen trial, beta-carotene supplements had no overall effect on skin aging [1].

Why wrinkles form

Development of facial wrinkles reflects damage to the dermis, the collagen-rich layer beneath the surface. Two processes overlap. Chronological (intrinsic) aging slowly thins the skin and reduces collagen production. Photoaging adds to this: ultraviolet light generates reactive oxygen molecules and activates enzymes that cut collagen fibers, while also suppressing new collagen synthesis. Fragmented collagen provides less mechanical support to the fibroblasts (the cells that make collagen), which then produce even less, so the damage tends to perpetuate itself. Sun-damaged skin also accumulates disorganized elastic material (solar elastosis) [11]. On top of this structural weakening, repeated muscle movement creases the skin in the same lines thousands of times a day. At first these are dynamic lines, visible only with expression; over time they become static lines etched into the skin at rest. Other theories exist, such as the "misrepair-accumulation" hypothesis, which proposes that wrinkles result from imperfect repair of collagen and elastic fibers repeatedly injured by stretching and compression, but these have not been widely tested.

Treatment options

Different kinds of wrinkles respond to different treatments, and most people benefit from a combination:

  • Prevention and topical care: daily sunscreen, avoiding tobacco, and a topical retinoid, as described above. These are the foundation for every other treatment.

  • Dynamic lines (frown lines, forehead lines, crow's feet) respond to neurotoxin injections, which relax the muscles that crease the skin. In a meta-analysis of randomized trials, side effects were generally mild; headache and, uncommonly, a temporarily drooping eyelid were the most notable after treatment of frown lines [43]. Fillers restore lost volume in deeper folds. See injectables.

  • Fine lines, rough texture, and sun damage respond to resurfacing with chemical peels, lasers, or microneedling, which remove or injure the outer skin in a controlled way to stimulate new collagen. See skin resurfacing.

  • Sagging skin and deep folds of the jowls, neck, and brow are mainly a result of chronological aging and gravity rather than sun damage [13], and creams or resurfacing cannot lift them. Surgical repositioning is the effective treatment. See face, neck, and brow lift.

DYSCHROMIAS- alterations of pigmentation

Dyschromia refers to an alteration of the color of the skin or nails.

Hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin. Hyperpigmentation can be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris. People with darker skin tones are more prone to hyperpigmentation, especially with excess sun exposure [44].

Many forms of hyperpigmentation are caused by an excess production of melanin. Hyperpigmentation can be diffuse or focal, affecting such areas as the face and the back of the hands. Melanin is produced by melanocytes at the lower layer of the epidermis. Melanin is a class of pigment responsible for producing colour in the body in places such as the eyes, skin, and hair. As the body ages, melanocyte distribution becomes less diffuse and its regulation less controlled by the body. UV light stimulates melanocyte activity, and where concentration of the cells is greater, hyperpigmentation occurs. Another form of hyperpigmentation is post inflammatory hyperpigmentation. These are dark and discoloured spots that appear on the skin following acne or other inflammation that has healed.

Any new, changing, or irregular dark spot should be examined, because melanoma and other skin cancers can look like harmless pigment at first. See skin cancers.

Sun spots (solar lentigines)

Flat brown "age spots" or "liver spots" on the face and hands are a direct result of chronic ultraviolet exposure. A systematic review of 41 clinical trials found light- and laser-based treatments the most reliable: intense pulsed light cleared lesions in about 75 to 90 percent of cases, Q-switched lasers in about 36 to 77 percent, and picosecond lasers in about 68 to 93 percent. Prescription lightening creams were effective in about half or more, and cryotherapy (freezing) worked but caused more side effects, such as light or dark marks [45]. Intense pulsed light and other aesthetic skin treatments are offered in the practice. Without sun protection, new spots continue to form.

Melasma

Melasma is a chronic, symmetrical brown or gray-brown patchiness of the cheeks, forehead, upper lip, or jaw, most common in women and in people with medium to darker skin, and often triggered by sunlight, pregnancy, or hormonal contraception. It tends to recur, so treatment is a long-term plan rather than a single cure.

  • Sun protection with a broad-spectrum sunscreen is essential to every treatment plan [46].

  • Topical treatment. Triple combination cream (hydroquinone, tretinoin, and a mild corticosteroid) is the most effective and best-studied treatment, followed by hydroquinone alone [47]. In a Cochrane review, triple combination cream was about 1.6 times as likely as hydroquinone alone to lighten melasma [48]. Because hydroquinone and topical steroids can cause problems with prolonged unsupervised use, international consensus recommends regulated, supervised use; azelaic acid and kojic acid are alternatives [46].

  • Tranexamic acid. This medication, taken by mouth, applied topically, or injected, reduced melasma severity in a meta-analysis of 22 randomized trials (1,280 patients), with oral treatment producing the largest effect [49]. Low doses (such as 500 mg a day) for 8 to 12 weeks are effective, and studies have not shown an increase in blood clots, but patients are screened for clotting risk factors before starting [50].

  • Procedures. Chemical peels, microneedling, and lasers are adjuncts. In controlled trials they are equal or inferior to topical treatment and carry a higher risk of side effects, including worsening pigmentation, so they are generally reserved for melasma that does not respond to topical and oral therapy [47, 46].

Post-inflammatory hyperpigmentation

Dark marks after acne, a rash, an injury, or a cosmetic procedure are especially common and persistent in darker skin. Treatment starts with controlling the underlying inflammation (for example, treating the acne) and daily sunscreen. Topical lightening agents such as hydroquinone, azelaic acid, retinoids, and niacinamide help epidermal pigment; peels and lasers are reserved for resistant cases and must be used cautiously, because irritation itself can make the pigmentation worse [44].

Hypopigmentation

Hypopigmentation is characterized specifically as an area of skin becoming lighter than the baseline skin color, but not completely devoid of pigment. This is not to be confused with depigmentation, which is characterized as the absence of all pigment. It is caused by melanocyte or melanin depletion, or a decrease in the amino acid tyrosine, which is used by melanocytes to make melanin. Some common genetic causes include mutations in the tyrosinase gene or OCA2 gene. As melanin pigments tend to be in the skin, eye, and hair, these are the commonly affected areas in those with hypopigmentation.

Hypopigmentation is common. Small white spots on sun-exposed forearms and shins, light patches after inflammation or injury, and lightening after aggressive resurfacing are frequent examples. Hypopigmentation can be upsetting to some, especially those with darker skin whose hypopigmentation marks are seen more visibly. Most causes of hypopigmentation are not serious, but lost pigment is often harder to restore than excess pigment is to remove, which is one reason resurfacing treatments are matched carefully to skin type.

Summary

The most effective skin care is simple and daily: broad-spectrum sunscreen, no tobacco, a gentle cleanser, a moisturizer, and a topical retinoid. Daily sunscreen measurably slows skin aging and reduces skin cancer, and smoking measurably accelerates aging, as studies of identical twins show. Acne, rosacea, and pigment disorders such as melasma now have well-graded treatment options, from topical medications to isotretinoin, tranexamic acid, and light-based treatments. Wrinkles are treated according to their cause: retinoids and resurfacing for fine lines and sun damage, neurotoxins and fillers for expression lines and volume loss, and surgery for sagging.

Last reviewed: October 4, 2026

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