Lotions and potions

 | March 1, 2007

Lotions and potions

A widely advertised face cream sells for $135 per 6-ounce tube. Its claim to wrinkle-smoothing fame: a "patented oligo-peptide." Would you buy it? Another skin care company contends that its "mineral complex of magnesium, zinc, and copper has been optimized to provide visible reductions even in deep wrinkles." Do you believe it? Because the FDA doesn't regulate these claims, how do you know which to believe? Even if the ingredients aren't harmful, at often exorbitant prices they could remove more cash from your wallet than wrinkles from your skin.

With the exception of colors and certain prohibited ingredients, a cosmetics manufacturer can use essentially any raw material in a product and market it without prior FDA approval. This gap in oversight is a cause of concern because of the growth in recent years of cosmeceuticals, chemicals in cosmetics that have physiological effects, such as boosting collagen production and inhibiting sun damage to reduce wrinkles (see "Cosmeceuticals"). Several cosmeceuticals have therapeutic effects, but because they are not classified as drugs, they are exempt from government regulations.

Although cosmetic claims are allowed without scientific substantiation, if a cosmetic makes a medical claim, such as removing dandruff or altering skin structure or function, the product is regulated as a drug for which scientific studies demonstrating safety and effectiveness must be submitted to the FDA.

If you're wondering whether a lotion or cream will do what it claims, remember that only a few substances have a scientifically demonstrated ability to reduce or prevent wrinkles in controlled studies. Such substances are discussed in the following pages. Most of the ingredients in skin care products aren't harmful, but while you may enjoy their fragrance, texture, or temporary effects, think twice about investing too much hope or cash in unproven promises.

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Moisturizers

A good moisturizer is one of the foundations of an effective skin care regimen for dry, older skin. Moisturizers can soothe dry skin and make wrinkles less noticeable, even though the effect is temporary. But with so many to choose from, how do you pick one?

Petroleum jelly is one of the best and most inexpensive products, especially when used right after bathing to seal in moisture. But most people dislike using it on their face because of its greasy look and feel. Likewise, thick, greasy-feeling emollients and ointments are best left for other parts of the body. Instead, creams and lotions usually are the facial moisturizers of choice for a couple of reasons. They contain water (ointments are all oil), so they don't feel as greasy. And many creams and lotions are humectants, an oil-free class of moisturizer that binds water to skin, so the smoothing, softening effects may last longer.

Most moisturizers contain water, glycerin, petrolatum, stearic acid, propylene glycol, and lanolin. Some contain botanical ingredients, such as jojoba oil, coconut oil, safflower oil, and linoleic acid, which help maintain the skin's outer layer of keratin and natural oils that keeps skin supple. Manufacturers use other ingredients, such as cetyl alcohol, palmitic acid, and dimethicone, to give moisturizers a creamy, velvety, or translucent look and feel, and to help shore up the "mortar" that keeps skin soft and smooth.

Many moisturizers also contain sunscreens and cosmeceuticals, which may help prevent or even correct fine wrinkles, uneven skin pigmentation, and other signs of aging and photoaging.

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Exfoliants

Moisturizers that contain exfoliant ingredients can improve the appearance of the skin by removing dead surface skin cells. As a result, they can smooth the skin's appearance and even out some discoloration from too much sun exposure. Exfoliants can be particularly useful for aging skin that appears rough and sallow, because older skin doesn't slough off dead surface skin cells as easily as younger skin does.

Two chemical exfoliants, alpha hydroxy acids (AHAs) and beta hydroxy acids (BHAs), are considered superior to many exfoliating scrubs, masks, soaps, toners, and abrasive cloths (see below). That's because they change cell growth patterns and may help renew collagen.

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Cosmeceuticals

Some cosmetics contain ingredients, known in the cosmetic industry as cosmeceuticals, that have medicinal or druglike benefits. These agents, which include vitamins, growth factors, and peptides, are found in products prescribed by dermatologists and many others that are available over the counter. The FDA does not recognize the term cosmeceutical but regulates some of the substances and makes recommendations on others. Several cosmeceuticals show promise against skin aging and photoaging. Studies show that they diminish wrinkles and age spots, smooth skin texture, and reduce the yellow hue that comes with age.

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Alpha hydroxy acids

AHAs are obtained from various fruits, including grapes, citrus fruits, and apples. Look for them on product labels as glycolic acid, lactic acid, malic acid, hydroxycaprylic acid, alpha-hydroxyoctanoic acid, triple fruit acid, or sugar cane extract. Although the FDA does not regulate AHAs as drugs, it has issued guidelines on their safe use because they can cause skin irritation and increase skin sensitivity to UV rays. The FDA has cautioned consumers only to use products that contain an AHA concentration of 10% or less and a pH of 3.5 or more (lower pH numbers are more acidic), and to use a sunscreen in conjunction with AHA-containing products. AHAs, particularly glycolic acid, are used in chemical peels in concentrations of 20%–30% and higher. An FDA review panel concluded that cosmetologists or skin aestheticians could safely use glycolic acid and lactic acid at concentrations not greater than 30% and with a pH not lower than 3.0 for brief skin care sessions provided that thorough rinsing and daily sun protection follow. In higher concentrations, AHAs are applied by physicians.

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Beta hydroxy acids

BHAs, another type of cosmetic exfoliant, are believed to smooth skin without some of the irritating effects of AHAs. The most widely used BHA is salicylic acid, a relative of aspirin. That salicylic acid has anti-inflammatory properties and doesn't penetrate to the dermal layer may explain why it's less irritating than AHAs. Moreover, salicylic acid is more effective than AHAs for exfoliating oily areas of the skin, which makes it useful if you have oily skin or if you're having problems with adult acne.

Salicylic acid and other BHAs can be found in many acne products at effective levels of 1.5%–2%. But antiwrinkle products containing these ingredients tend not to list the percentage on their labels, so it's difficult to know whether they contain sufficient amounts to be effective. Other BHAs include beta hydroxybutanoic acid, tropic acid, and trethocanic acid.

The FDA recommends that you first test BHAs on a small patch of skin to see if irritation occurs, and that you use a sunscreen with BHA products because they can increase the skin's sun sensitivity.

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Vitamins and antioxidants

Some of the most confusing questions in skin care concern the use of vitamins and antioxidants (such as vitamins A, C, and E) and ubiquinone (coenzyme Q10). In theory, the use of these substances in moisturizers and other cosmetics makes sense. At the cellular level, antioxidants ward off damage from molecules called free radicals, which cause oxidative deterioration.

Some vitamins and antioxidants are beneficial when applied to the skin. Derivatives of vitamin A are active ingredients in retinoids, drugs that reduce photodamage and increase collagen production (see "Retinoids"). A 10% concentration of vitamin C significantly reduced fine wrinkles, made skin smoother, and improved skin tone and sallow hue in one 12-week clinical trial. Other studies have reported that vitamin C helped repair elastic tissue and increase collagen, and that vitamin B₃ (niacinamide) reduced signs of photoaging as well as the cancer-causing effects of ultraviolet radiation.

Coenzyme Q10, a naturally occurring antioxidant, has also been shown to reduce wrinkles and guard against ultraviolet light damage. A 12-week clinical trial of lipoic acid, another antioxidant, reported a significant decrease in wrinkles, age spots, and roughness. Copper, an antioxidant metal, may play a role in collagen and elastin production.

Some moisturizers and other skin care products contain vitamin E, but no clinical studies have shown that it can prevent or reverse signs of photoaging.

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Growth factors

Hundreds of growth factors occur naturally in the human body to help heal wounds by promoting new tissue formation. Several studies have found that creams with different combinations of these substances diminish wrinkles. A study published in Dermatologic Surgery in 2006 compared the effects of two different creams containing growth factors with a third cream that contained vitamin C. After three months, physicians, not knowing which subjects used which cream, found that those who had used the growth factor products had the greatest reduction of wrinkles.

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Peptides

These compounds, which have various roles in the body, are used as cosmeceuticals for different effects. Some peptides stimulate the production of collagen and elastin. Others stabilize copper (an antioxidant metal shown to reduce wrinkles), improve skin elasticity, and reverse other signs of photoaging.

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Retinoids

Topical vitamin A–based drugs called retinoids reduce wrinkles. Tretinoin (Retin-A, Renova), adapalene (Differin), and tazarotene (Avage) are prescription drugs used in skin care. Tretinoin, under the brand name Retin-A, was first used as an acne treatment in the 1970s, but researchers later discovered that it fades actinic keratosis spots and speeds the turnover of superficial skin cells. In 1996 the FDA approved Renova, an emollient cream containing a 0.05% concentration of tretinoin, as the first drug to treat wrinkles. Similarly, the retinoid tazarotene is prescribed under the brand name Avage as a wrinkle treatment. Other retinoids are undergoing clinical trials.

Retinoids reduce fine lines and wrinkles by increasing the production of collagen. They also stimulate the production of new blood vessels in the skin, which improves skin color. Additional benefits include fading liver spots and softening rough patches of skin. It takes 3 to 6 months of regular use before improvements in wrinkles are apparent; the best results take 6 to 12 months. Because retinoids can cause skin irritation, doctors often recommend using them only every other day at first and then gradually working up to nightly applications. Wear a sunscreen during the day, because retinoids increase the skin's sensitivity to sunlight. These drugs must be used continually to maintain their benefits.

Several over-the-counter products containing retinoids, such as Retinol, are now available. They may not be as effective in reducing wrinkles as tretinoin, but they do improve the appearance of photoaged skin. Tretinoin can be used with AHAs for additional skin-smoothing effects.

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Other skin care products

Muds, etc. What about the salts, mud, and clay that are purported to have natural minerals that restore youthful softness and luster to your skin? The size of their molecules is generally too large to penetrate the skin, and there are no scientific data to back up their claims.

Products from plant sources. Lotions and creams with extracts from plants such as seaweed, fruits, or herbs may have a pleasant scent and come attractively packaged. In addition to AHAs, some other plant-based ingredients may reduce or prevent wrinkles, but so far the evidence comes from small clinical studies and animal research. Green tea, an antioxidant, may protect against UV damage and inhibit photoaging; genistein, an antioxidant derived from soy, may also inhibit UV damage; kinetin (N6-furfuryladenine), an antioxidant, may improve skin texture and tone and reduce wrinkles; and date palm extract may reduce wrinkles around the eyes.

Dimethylaminoethanol (DMAE). This is a neurotransmitter, a substance produced in the brain. An 18-week clinical trial found that a gel containing a 3% extract of DMAE reduced forehead frown lines, tightened sagging neck skin, and decreased dark circles around the eyes.

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What to avoid

It's always important to read the ingredients labels of creams and lotions, especially if you have sensitive skin. Some may contain substances that will irritate it. The American Academy of Dermatology says these skin care product ingredients should be avoided by people with sensitive skin:

preservatives; the least irritating preservatives are parabens, such as methyl paraben and butyl paraben

botanical or antibacterial ingredients

solvents that penetrate the skin, including propylene glycol and ethanol. A better alternative is polyethylene glycol, which does not penetrate the skin.

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Review Date: 2007-03-01

Harvard Medical School does not endorse products or services.